1985 SVO turbo 2.3 turns over no start
- Thread starter John W Schutt
- Start date
-
Sponsors (?)
Give it a quick shot of starting fluid, just a little, if it tries to start you'll need a fuel pump, probably a good idea to change it anyway, don't try to run it with the starting fluid, you just want to see if it tries.
how many miles on this?
how many miles on this?
Please keep in mind that this checklist was written for a 5.0 Fox body Mustang, but it will work for your EFI Turbo 4
Cranks OK, but No Start Checklist for Fuel Injected 5.0 Mustangs model years 1986-1995
A word about this checklist before you start: it is arranged in a specific order to put the most likely failure items first. That will save you time, energy and money. Start at the top of the list and work your way down. Jumping around will possibly cause you to miss just what you need to see to find and fix the problem. Don’t skip any steps because the next step depends on the last step working correctly.
Revised 26-Jul-2017 to add fuse link diagram.
All text applies to all models unless stated otherwise.
Note: 94-95 specific changes are in red
1.) Remove push on connector (small red/blue wire) from starter solenoid and turn ignition switch to the Run position. Place car in neutral or Park and set the parking brake. Remove the coil wire from distributor & and hold it 3/8” away from the engine block. Jumper the screw to the big bolt on the starter solenoid that has the battery wire connected to it. You should get a nice fat blue spark.
Most of the items are electrical in nature, so a test light, or even better, a voltmeter, is helpful to be sure they have power to them.
No spark, possible failed items in order of their probability:
A.) MSD, Crane, or other ignition box if present - Bypass it and return to stock configuration if possible. Do this as a temporary measure to eliminate it as a possible problem source.
B.) PIP sensor in distributor. The PIP sensor supplies the timing pulse to trigger the TFI and injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed. See paragraph 5A – Using a noid light will tell if the PIP is working by flashing when the engine is cranking.
C.) TFI module: use a test light to check the TFI module. Place one lead of the test light on the red/green wire on the ignition coil connector and the other lead on the dark green/yellow wire on the ignition coil connector. If the TFI is working properly, the test light will flash when the engine is cranked using the ignition switch.
D.) Coil
E.) No EEC or computer power - EEC or computer relay failure
86-93 models only: EEC relay next to computer - look for 12 volts at the fuel injector red wires.
94-95 models only: EEC or PCM power relay in the constant control relay module. Look for 12 volts at the fuel injector red wires.
Both 86-93 and 94-95 models: No 12 volts with the ignition switch in the run position on the fuel injector red wires. The relay has failed or there is no power coming from the ignition switch. Make sure that there is 12 volts on the red/green wire on the coil before replacing the relay.
F.) No EEC or computer power - fuse or fuse link failure
86-93 models only: Fuse links in wiring harness - look for 12 volts at the fuel injector red wires. All the fuse links live in a bundle up near the starter solenoid. Look for a 20 gauge blue fuse link connected to 2 black/orange 14 gauge wires.
94-95 models only: 20 amp EEC fuse in the engine compartment fuse box. Look for 12 volts at the fuel injector red wires.
G.) Ignition switch - look for 12 volts at the ignition coil red/lt green wire. No 12 volts, blown fuse link or faulty ignition switch. Remove the plastic from around the ignition switch and look for 12 volts on the red/green wire on the ignition switch with it in the Run position. No 12 volts and the ignition switch is faulty. If 12 volts is present in the Run position at the ignition switch but not at the coil, then the fuse or fuse link is blown.
Note: fuses or fuse links blow for a reason. Don’t replace either a fuse or fuse link with one with a larger rating than stock. Doing so invites an electrical fire.
Ignition fuse links may be replaced with an inline fuse holder and 5 amp fuse for troubleshooting purposes.
94-95 models only: Check inside fuse panel for fuse #18 blown – 20 amp [fuse
H.) Missing or loose computer power ground. The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery.
In 86-90 model cars, it is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.
In 91-95 model cars it is a black cylinder about 2 1/2" long by 1" diameter with a black/white wire.
You'll find it up next to the starter solenoid where the wire goes into the wiring harness
I.) Computer. Don’t replace the computer just because you don’t understand how it works. Computers seldom fail, it usually is a sensor or wiring problem that causes the problems.
J.) Bad or missing secondary power ground. It is located between the back of the intake manifold and the driver's side firewall. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.
K.) Engine fires briefly, but dies immediately when the key is released to the Run position. Crank the engine & when it fires off, pull the small push on connector (red/blue wire) off the starter relay (Looks like it is stuck on a screw). Hold the switch in the crank position: if it continues to run there is a problem with either the ignition switch or TFI module. Check for 12 volts at the red/green wire on the coil with the switch in the Run position. Good 12 volts, then replace the TFI.
See the Ignition switch wiring diagram for more information on the ignition wiring fuse link because it is the next thing to be tested. You will need a Multimeter or DVM and know how to use the Ohms function to check continuity between the red/green wire on the ignition coil and the red/green wire on the ignition switch. Make sure that the ignition switch is in the off position when you do the check. You should see less than 1 Ω (Ohm) between the red/green wire on the coil and the red/green wire on the ignition switch. More than 1 Ω means that the fuse link may have blown open and needs to be replaced. If you get 1 Ω or less means the fuse link is OK and the ignition switch is bad.
Wiring Diagrams:
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information Everyone should bookmark this site.
Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif
Complete computer, actuator & sensor wiring diagram for 94-95 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif
AutoZone wiring diagrams: You can navigate to the diagrams yourself via Repair Info | AutoZone.com and select the car year, make, model and engine. That will enable you to bring up the wiring diagram for your particular car.
2.) Spark at coil wire, pull #1 plug wire off at the spark plug and check to see spark. No spark, possible failed items in order of their probability: [/b]
A.) Moisture inside distributor – remove cap, dry off & spray with WD40
B.) Distributor cap
C.) Rotor
D.) Spark Plug wires
E.) Coil weak or intermittent - you should see 3/8" fat blue spark with a good coil
3.) Spark at spark plug, but no start.
Next, get a can of starting fluid (ether) from your local auto parts store: costs a $1.30 or so. Then pull the air duct off at the throttle body elbow, open the throttle, and spray the ether in it. Reconnect the air duct and try to start the car. Do not try to start the car without reconnecting the air duct.
Two reasons:
1.) If it backfires, the chance for a serious fire is increased.
2.) On Mass Air cars, the computer needs to measure the MAF flow once the engine starts.
If it starts then, you have a fuel management issue. Continue the checklist with emphasis of fuel related items that follow. If it doesn’t, then it is a computer or timing issue: see Step 4.
Clue – listen for the fuel pump to prime when you first turn the ignition switch on. It should run for 2-4 seconds and shut off. To trick the fuel pump into running, find the EEC test connector and jump the connector in the Upper RH corner to ground. The EEC connector is near the wiper motor and LH hood hinge.
If the relay & inertia switch are OK, you will have power to the pump. Check fuel pressure – remove the cap from the Schrader valve behind the alternator and depress the core. Fuel should squirt out, catch it in a rag. Beware of fire hazard when you do this. In a pinch, you can use a tire pressure gauge to measure the fuel pressure. It may not be completely accurate, but you will have some clue as to how much pressure you have. If you have any doubts about having sufficient fuel flow/pressure, rent a fuel pressure test gauge from the auto parts store. That will tell you for sure if you have adequate fuel pressure.
4.) No fuel pressure, possible failed items in order of their probability:
A.) Tripped inertia switch – Coupe & hatch cars hide it under the plastic trim covering the driver's side taillight. Use the voltmeter or test light to make sure you have power to both sides of the switch
B.) Fuel pump power relay – located under the driver’s seat in most stangs built before 92. On 92 and later model cars it is located below the Mass Air Flow meter. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
C.) Clogged fuel filter
D.) Failed fuel pump
E.) 86-90 models only: Blown fuse link in wiring harness. Look for 12 volts at the Orange/Lt Blue wire on the fuel pump relay.
91-93 models only Blown fuse link in wiring harness. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
The fuse links for all model years 86-93 live in the wiring harness near the starter solenoid.
94-95 models only: 20 amp fuel pump fuse in the engine compartment fuse box. Look for 12 volts at the Dark green/yellow wire on the constant control relay module.
F.) Engine seem to load up on fuel and may have black smoke at the tailpipe. Fuel pressure regulator failed. Remove the vacuum line from the regulator and inspect for fuel escaping while the pump is running. If fuel is coming out the vacuum port, the regulator has failed. Check the regulator vacuum line for fuel too. Disconnect it from the engine and blow air though it. If you find gas, the regulator has failed.
5.) Fuel pressure OK, the injectors are not firing.
A.) The PIP sensor in the distributor tells the computer when to fire the injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed.
A noid light available from any auto parts store, is one way to test the injector circuit to see if the injectors are firing. The noid light plugs into the fuel injector harness in place of any easily accessible injector. Plug it in and try to start the engine: it will flash if the injector is firing.
I like to use an old injector with compressed air applied to the injector where the fuel rail would normally connect. I hook the whole thing up, apply compressed air to the injector and stick it in a paper cup of soapy water. When the engine cranks with the ignition switch on, if the injector fires, it makes bubbles. Cheap if you have the stuff laying around, and works good too.
B.) Pull an injector wire connector off and look for 12 volts on the red wire when the ignition switch is on.
C.) No power, then look for problems with the 10 pin connecter (salt & pepper shakers at the rear of the upper manifold).
See the graphic for the 10 pin connector circuit layout.
The injector power pin is the VPWR pin in the black 10 pin connector.
D.) No power and the 10 pin connections are good: look for broken wiring between the orange/black wire on the EEC relay and the red wire for the 10 pin connectors.
E.) TPS voltage exceeds 3.7 volts with the throttle closed. This will shut off the injectors, since the computer uses this strategy to clear a flooded engine. Use a DVM, a pair of safety pins, and probe the black/white and green wires to measure the TPS voltage.
On a 94-95 Mustang, probe the black/white and grey/white wires to measure the TPS voltage.
It should be .5-.1.0 volts with the key on, engine not running. Note that if the black/white wire (signal ground) has a bad connection, you will get some strange readings. Make a second measurement using the battery post as the ground to eliminate any ground problems. If the readings are different by more than 5%, you may have a high resistance condition in the black/white signal ground circuit.
6.) Spark & fuel pressure OK.
A.) Failed IAB or improperly set base idle (no airflow to start engine). Press the throttle ¼ way down and try to start the car. See the "Surging Idle Checklist for help with all your idle/stall problems.
B.) Failed computer (not very likely)
C.) Engine ignition or cam timing off: only likely if the engine has been worked on recently. If you removed the distributor, there is a good probability that you installed it 180 degrees out of time.
D.) Firing order off: HO & 351 use a different firing order from the non HO engines.
HO & 351W 1-3-7-2-6-5-4-8
Non HO 1-5-4-2-6-3-7-8
E.) No start when hot - Press the throttle to the floor & try starting it, if you get this far. If it starts, replace the ECT.
F. ) Engine that has had the heads off or valves adjusted. Do a compression test to make sure the valves are not adjusted too tight. You should have a minimum of 90 PSI on a cold engine.
Barn car find checklist: first steps to get it back on the road.
First of all, carefully check the underhood area to make sure that rodents haven’t had a feast on the electrical wiring, air ducts and vacuum lines. Replace and repair any visible damage. Replace the battery if you haven’t already done so.
Next, drain ALL the engine fluids, transmission fluid, pump the fuel tank and fuel lines clear.
Get several cans of brake fluid, you will need it to flush the brakes. Loosen all 4 brake bleeders one at a time and flush the brake system by pumping the brake pedal. You will need to bleed the brakes when you finish flushing them. Brake fluid absorbs moisture if it sits for a long time and corrosive compounds start to brew themselves in the brake system.
Pumping out the old gas - do this before replacing the fuel filter if possible;
If the old pump still works, you can use it to pump the tank out.
1.) Separate the pressure line (the one with the Schrader valve on it) using the fuel line tools.
Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling.
OR
View: https://www.youtube.com/watch?v=vRTjYAxvaCs
Use a piece of garden hose to run from the pressure line to your bucket or gas can. Make sure it is as leak proof as you can make it. Fire and explosion are not part of the repair process...
2.) Jumper the fuel pump’s test point to ground.
Foxbody Diagnostic connector
Foxbody Diagnostic connector close up view[/b]
Turn the ignition switch to the Run position. the fuel pump will pump the tank almost dry unless the battery runs down first.
Some 5 gallon paint pails lined with garbage bags are good to hold the gas. The garbage bags provide a clean liner for the pails and keep the loose trash out of the gas. If you decide to use a siphon, a piece of 1/2" garden hose stuck down the filler neck will siphon all but a gallon or so of the gas.
The fuel filter is on the passenger side of the car on the body just over the rear axle housing. Pull the plastic clips out by grasping the tabs with a pair of needle nose pliers or a screwdriver.
]View: https://www.youtube.com/watch?v=i-JU54w7FL4]
At this point you have fresh engine fluids, fresh gasoline, new filters, new battery fresh brake fluid, and have replaced or repaired any rodent damage.
Then change ALL the filters (fuel, air & oil). Then put in new oil, new antifreeze, and 5 gallons or so of new gasoline. Be sure to replace the all the fan belt or belts. Reusing old belts are an invitation to break and leave you stranded or overheated.
Pull the spark plugs out and squirt some oil down inside the cylinders to lube them up. While the spark plugs are out, examine them for signs of damage or fouling. Write down which plug came from which cylinder and write down any negative things that you saw when you examined the spark plugs.
This next step is for those who have successfully removed and reinstalled a 5.0 Mustang distributor. Pre-oil the engine to insure that everything is lubed up good before the engine starts. Turn the engine up to where the distributor rotor points to #1 cylinder. Mark the distributor base with a scratch mark or something else that isn’t going to get rubbed off. Then remove the distributor and stick a ¼” socket on a12” extension on an electric drill. Place this rig on the oil pump shaft in the hole below the distributor. Turn the ignition switch to Run but don’t crank the engine. Run the drill counterclockwise while your assistant watches the oil pressure gauge.
For the less experienced DIY’er, here is a less complicated procedure.
While the spark plugs are out, crank the engine until you see the oil pressure gauge indicate pressure. If you don’t see any indication of oil pressure at the gauge after 30 seconds or so of cranking, you have some other problems. This is the time to stop and investigate them.
Put the old spark plugs back in if they look good; replace the ones that don’t. Have a spare set of new spark plugs handy for installation once you get the engine running. Why? The oil you squirted in the cylinders will lube things up, but it may also foul the spark plugs. Don’t foul the new plugs by putting them in cylinders that may oil foul the plugs.
Remove the distributor cap, and examine it and the rotor for signs of moisture and tracks. Lightly spray the inside of the distributor cap with WD40 to displace any moisture, and then wipe it up with a clean paper towel. Replace any cap or rotor that shows signs of damage, excessive corrosion or tracking that won’t wipe up with a shot of WD40.
Put the distributor cap back on, secure any loose wiring, vacuum lines, check the fluid levels, check belt tension and tighten any fasteners that you may have loosened. You are now ready to see if the engine will run.
Is this a carb or Fuel Injection car?
Cranks OK, but No Start Checklist for Fuel Injected 5.0 Mustangs model years 1986-1995
A word about this checklist before you start: it is arranged in a specific order to put the most likely failure items first. That will save you time, energy and money. Start at the top of the list and work your way down. Jumping around will possibly cause you to miss just what you need to see to find and fix the problem. Don’t skip any steps because the next step depends on the last step working correctly.
Revised 26-Jul-2017 to add fuse link diagram.
All text applies to all models unless stated otherwise.
Note: 94-95 specific changes are in red
1.) Remove push on connector (small red/blue wire) from starter solenoid and turn ignition switch to the Run position. Place car in neutral or Park and set the parking brake. Remove the coil wire from distributor & and hold it 3/8” away from the engine block. Jumper the screw to the big bolt on the starter solenoid that has the battery wire connected to it. You should get a nice fat blue spark.
Most of the items are electrical in nature, so a test light, or even better, a voltmeter, is helpful to be sure they have power to them.
No spark, possible failed items in order of their probability:
A.) MSD, Crane, or other ignition box if present - Bypass it and return to stock configuration if possible. Do this as a temporary measure to eliminate it as a possible problem source.
B.) PIP sensor in distributor. The PIP sensor supplies the timing pulse to trigger the TFI and injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed. See paragraph 5A – Using a noid light will tell if the PIP is working by flashing when the engine is cranking.
C.) TFI module: use a test light to check the TFI module. Place one lead of the test light on the red/green wire on the ignition coil connector and the other lead on the dark green/yellow wire on the ignition coil connector. If the TFI is working properly, the test light will flash when the engine is cranked using the ignition switch.
D.) Coil
E.) No EEC or computer power - EEC or computer relay failure
86-93 models only: EEC relay next to computer - look for 12 volts at the fuel injector red wires.
94-95 models only: EEC or PCM power relay in the constant control relay module. Look for 12 volts at the fuel injector red wires.
Both 86-93 and 94-95 models: No 12 volts with the ignition switch in the run position on the fuel injector red wires. The relay has failed or there is no power coming from the ignition switch. Make sure that there is 12 volts on the red/green wire on the coil before replacing the relay.
F.) No EEC or computer power - fuse or fuse link failure
86-93 models only: Fuse links in wiring harness - look for 12 volts at the fuel injector red wires. All the fuse links live in a bundle up near the starter solenoid. Look for a 20 gauge blue fuse link connected to 2 black/orange 14 gauge wires.
94-95 models only: 20 amp EEC fuse in the engine compartment fuse box. Look for 12 volts at the fuel injector red wires.
G.) Ignition switch - look for 12 volts at the ignition coil red/lt green wire. No 12 volts, blown fuse link or faulty ignition switch. Remove the plastic from around the ignition switch and look for 12 volts on the red/green wire on the ignition switch with it in the Run position. No 12 volts and the ignition switch is faulty. If 12 volts is present in the Run position at the ignition switch but not at the coil, then the fuse or fuse link is blown.
Note: fuses or fuse links blow for a reason. Don’t replace either a fuse or fuse link with one with a larger rating than stock. Doing so invites an electrical fire.
Ignition fuse links may be replaced with an inline fuse holder and 5 amp fuse for troubleshooting purposes.
94-95 models only: Check inside fuse panel for fuse #18 blown – 20 amp [fuse
H.) Missing or loose computer power ground. The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery.
In 86-90 model cars, it is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.
In 91-95 model cars it is a black cylinder about 2 1/2" long by 1" diameter with a black/white wire.
You'll find it up next to the starter solenoid where the wire goes into the wiring harness
I.) Computer. Don’t replace the computer just because you don’t understand how it works. Computers seldom fail, it usually is a sensor or wiring problem that causes the problems.
J.) Bad or missing secondary power ground. It is located between the back of the intake manifold and the driver's side firewall. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.
K.) Engine fires briefly, but dies immediately when the key is released to the Run position. Crank the engine & when it fires off, pull the small push on connector (red/blue wire) off the starter relay (Looks like it is stuck on a screw). Hold the switch in the crank position: if it continues to run there is a problem with either the ignition switch or TFI module. Check for 12 volts at the red/green wire on the coil with the switch in the Run position. Good 12 volts, then replace the TFI.
See the Ignition switch wiring diagram for more information on the ignition wiring fuse link because it is the next thing to be tested. You will need a Multimeter or DVM and know how to use the Ohms function to check continuity between the red/green wire on the ignition coil and the red/green wire on the ignition switch. Make sure that the ignition switch is in the off position when you do the check. You should see less than 1 Ω (Ohm) between the red/green wire on the coil and the red/green wire on the ignition switch. More than 1 Ω means that the fuse link may have blown open and needs to be replaced. If you get 1 Ω or less means the fuse link is OK and the ignition switch is bad.
Wiring Diagrams:
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information Everyone should bookmark this site.
Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif
Complete computer, actuator & sensor wiring diagram for 94-95 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif
AutoZone wiring diagrams: You can navigate to the diagrams yourself via Repair Info | AutoZone.com and select the car year, make, model and engine. That will enable you to bring up the wiring diagram for your particular car.
2.) Spark at coil wire, pull #1 plug wire off at the spark plug and check to see spark. No spark, possible failed items in order of their probability: [/b]
A.) Moisture inside distributor – remove cap, dry off & spray with WD40
B.) Distributor cap
C.) Rotor
D.) Spark Plug wires
E.) Coil weak or intermittent - you should see 3/8" fat blue spark with a good coil
3.) Spark at spark plug, but no start.
Next, get a can of starting fluid (ether) from your local auto parts store: costs a $1.30 or so. Then pull the air duct off at the throttle body elbow, open the throttle, and spray the ether in it. Reconnect the air duct and try to start the car. Do not try to start the car without reconnecting the air duct.
Two reasons:
1.) If it backfires, the chance for a serious fire is increased.
2.) On Mass Air cars, the computer needs to measure the MAF flow once the engine starts.
If it starts then, you have a fuel management issue. Continue the checklist with emphasis of fuel related items that follow. If it doesn’t, then it is a computer or timing issue: see Step 4.
Clue – listen for the fuel pump to prime when you first turn the ignition switch on. It should run for 2-4 seconds and shut off. To trick the fuel pump into running, find the EEC test connector and jump the connector in the Upper RH corner to ground. The EEC connector is near the wiper motor and LH hood hinge.
If the relay & inertia switch are OK, you will have power to the pump. Check fuel pressure – remove the cap from the Schrader valve behind the alternator and depress the core. Fuel should squirt out, catch it in a rag. Beware of fire hazard when you do this. In a pinch, you can use a tire pressure gauge to measure the fuel pressure. It may not be completely accurate, but you will have some clue as to how much pressure you have. If you have any doubts about having sufficient fuel flow/pressure, rent a fuel pressure test gauge from the auto parts store. That will tell you for sure if you have adequate fuel pressure.
4.) No fuel pressure, possible failed items in order of their probability:
A.) Tripped inertia switch – Coupe & hatch cars hide it under the plastic trim covering the driver's side taillight. Use the voltmeter or test light to make sure you have power to both sides of the switch
B.) Fuel pump power relay – located under the driver’s seat in most stangs built before 92. On 92 and later model cars it is located below the Mass Air Flow meter. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
C.) Clogged fuel filter
D.) Failed fuel pump
E.) 86-90 models only: Blown fuse link in wiring harness. Look for 12 volts at the Orange/Lt Blue wire on the fuel pump relay.
91-93 models only Blown fuse link in wiring harness. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
The fuse links for all model years 86-93 live in the wiring harness near the starter solenoid.
94-95 models only: 20 amp fuel pump fuse in the engine compartment fuse box. Look for 12 volts at the Dark green/yellow wire on the constant control relay module.
F.) Engine seem to load up on fuel and may have black smoke at the tailpipe. Fuel pressure regulator failed. Remove the vacuum line from the regulator and inspect for fuel escaping while the pump is running. If fuel is coming out the vacuum port, the regulator has failed. Check the regulator vacuum line for fuel too. Disconnect it from the engine and blow air though it. If you find gas, the regulator has failed.
5.) Fuel pressure OK, the injectors are not firing.
A.) The PIP sensor in the distributor tells the computer when to fire the injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed.
A noid light available from any auto parts store, is one way to test the injector circuit to see if the injectors are firing. The noid light plugs into the fuel injector harness in place of any easily accessible injector. Plug it in and try to start the engine: it will flash if the injector is firing.
I like to use an old injector with compressed air applied to the injector where the fuel rail would normally connect. I hook the whole thing up, apply compressed air to the injector and stick it in a paper cup of soapy water. When the engine cranks with the ignition switch on, if the injector fires, it makes bubbles. Cheap if you have the stuff laying around, and works good too.
B.) Pull an injector wire connector off and look for 12 volts on the red wire when the ignition switch is on.
C.) No power, then look for problems with the 10 pin connecter (salt & pepper shakers at the rear of the upper manifold).
See the graphic for the 10 pin connector circuit layout.
The injector power pin is the VPWR pin in the black 10 pin connector.
D.) No power and the 10 pin connections are good: look for broken wiring between the orange/black wire on the EEC relay and the red wire for the 10 pin connectors.
E.) TPS voltage exceeds 3.7 volts with the throttle closed. This will shut off the injectors, since the computer uses this strategy to clear a flooded engine. Use a DVM, a pair of safety pins, and probe the black/white and green wires to measure the TPS voltage.
On a 94-95 Mustang, probe the black/white and grey/white wires to measure the TPS voltage.
It should be .5-.1.0 volts with the key on, engine not running. Note that if the black/white wire (signal ground) has a bad connection, you will get some strange readings. Make a second measurement using the battery post as the ground to eliminate any ground problems. If the readings are different by more than 5%, you may have a high resistance condition in the black/white signal ground circuit.
6.) Spark & fuel pressure OK.
A.) Failed IAB or improperly set base idle (no airflow to start engine). Press the throttle ¼ way down and try to start the car. See the "Surging Idle Checklist for help with all your idle/stall problems.
B.) Failed computer (not very likely)
C.) Engine ignition or cam timing off: only likely if the engine has been worked on recently. If you removed the distributor, there is a good probability that you installed it 180 degrees out of time.
D.) Firing order off: HO & 351 use a different firing order from the non HO engines.
HO & 351W 1-3-7-2-6-5-4-8
Non HO 1-5-4-2-6-3-7-8
E.) No start when hot - Press the throttle to the floor & try starting it, if you get this far. If it starts, replace the ECT.
F. ) Engine that has had the heads off or valves adjusted. Do a compression test to make sure the valves are not adjusted too tight. You should have a minimum of 90 PSI on a cold engine.
Barn car find checklist: first steps to get it back on the road.
First of all, carefully check the underhood area to make sure that rodents haven’t had a feast on the electrical wiring, air ducts and vacuum lines. Replace and repair any visible damage. Replace the battery if you haven’t already done so.
Next, drain ALL the engine fluids, transmission fluid, pump the fuel tank and fuel lines clear.
Get several cans of brake fluid, you will need it to flush the brakes. Loosen all 4 brake bleeders one at a time and flush the brake system by pumping the brake pedal. You will need to bleed the brakes when you finish flushing them. Brake fluid absorbs moisture if it sits for a long time and corrosive compounds start to brew themselves in the brake system.
Pumping out the old gas - do this before replacing the fuel filter if possible;
If the old pump still works, you can use it to pump the tank out.
1.) Separate the pressure line (the one with the Schrader valve on it) using the fuel line tools.
Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling.
OR
View: https://www.youtube.com/watch?v=vRTjYAxvaCs
Use a piece of garden hose to run from the pressure line to your bucket or gas can. Make sure it is as leak proof as you can make it. Fire and explosion are not part of the repair process...
2.) Jumper the fuel pump’s test point to ground.
Foxbody Diagnostic connector
Foxbody Diagnostic connector close up view[/b]
Turn the ignition switch to the Run position. the fuel pump will pump the tank almost dry unless the battery runs down first.
Some 5 gallon paint pails lined with garbage bags are good to hold the gas. The garbage bags provide a clean liner for the pails and keep the loose trash out of the gas. If you decide to use a siphon, a piece of 1/2" garden hose stuck down the filler neck will siphon all but a gallon or so of the gas.
The fuel filter is on the passenger side of the car on the body just over the rear axle housing. Pull the plastic clips out by grasping the tabs with a pair of needle nose pliers or a screwdriver.
]View: https://www.youtube.com/watch?v=i-JU54w7FL4]
At this point you have fresh engine fluids, fresh gasoline, new filters, new battery fresh brake fluid, and have replaced or repaired any rodent damage.
Then change ALL the filters (fuel, air & oil). Then put in new oil, new antifreeze, and 5 gallons or so of new gasoline. Be sure to replace the all the fan belt or belts. Reusing old belts are an invitation to break and leave you stranded or overheated.
Pull the spark plugs out and squirt some oil down inside the cylinders to lube them up. While the spark plugs are out, examine them for signs of damage or fouling. Write down which plug came from which cylinder and write down any negative things that you saw when you examined the spark plugs.
This next step is for those who have successfully removed and reinstalled a 5.0 Mustang distributor. Pre-oil the engine to insure that everything is lubed up good before the engine starts. Turn the engine up to where the distributor rotor points to #1 cylinder. Mark the distributor base with a scratch mark or something else that isn’t going to get rubbed off. Then remove the distributor and stick a ¼” socket on a12” extension on an electric drill. Place this rig on the oil pump shaft in the hole below the distributor. Turn the ignition switch to Run but don’t crank the engine. Run the drill counterclockwise while your assistant watches the oil pressure gauge.
For the less experienced DIY’er, here is a less complicated procedure.
While the spark plugs are out, crank the engine until you see the oil pressure gauge indicate pressure. If you don’t see any indication of oil pressure at the gauge after 30 seconds or so of cranking, you have some other problems. This is the time to stop and investigate them.
Put the old spark plugs back in if they look good; replace the ones that don’t. Have a spare set of new spark plugs handy for installation once you get the engine running. Why? The oil you squirted in the cylinders will lube things up, but it may also foul the spark plugs. Don’t foul the new plugs by putting them in cylinders that may oil foul the plugs.
Remove the distributor cap, and examine it and the rotor for signs of moisture and tracks. Lightly spray the inside of the distributor cap with WD40 to displace any moisture, and then wipe it up with a clean paper towel. Replace any cap or rotor that shows signs of damage, excessive corrosion or tracking that won’t wipe up with a shot of WD40.
Put the distributor cap back on, secure any loose wiring, vacuum lines, check the fluid levels, check belt tension and tighten any fasteners that you may have loosened. You are now ready to see if the engine will run.
Is this a carb or Fuel Injection car?
Last edited:
Did you take off the fuel lines before storing the car? Did you hook them up backwards? Easy to do. Did you get firing order correct after you replaced the cap and plugs? All easy things to double check. If all is ok then you need to check for fuel and spark. The ^^ above post gives you ways to do that.
Let us know what you find out.
Let us know what you find out.
The easy way.
Shoot a little carb cleaner down a vacuum line that attaches to the front of the turbo and then go turn the key to start. Does it run briefly? If yes...you're starving for fuel. No? Either not enough carb cleaner, or you have a timing, or spark problem.
85's had two fuel pumps. The one in the fuel tank is a low pressure pump and then there's the one on the frame rail that is the high pressure pump. You can't get all the fuel out of them, so if it's been sitting that long, figure on replacing them. Most just replace the frame-mounted pump with another fuel filter, and then replace the in-tank pump with a Walbro that's designed for 87-93 Mustangs. Goes right in. The only issue with that is that there is a resistor inline with the in-tank pump wiring that has to be removed and then the wire spliced back together.
85.5 and 86 I don't think they used dual pumps. 84-85 did, IIRC. Does it have an inline upper intake manifold or a square intake? Inline would be 1984-1985, square ones were 85.5-86.
If in fact that you have to do the in-tank pump, I'd highly suggest looking closely down inside the tank. If you see rust, or the box is loose, replace the fuel tank and also figure on replacing the sending unit while you're there. Don't forget a new pair of grommets-one for the filler neck and the other for the vent valve assembly. Ideally you'd want this stuff on hand so that you don't have to fight it any more than you have to. Been there, done that, many times and I STILL haven't learned.
Shoot a little carb cleaner down a vacuum line that attaches to the front of the turbo and then go turn the key to start. Does it run briefly? If yes...you're starving for fuel. No? Either not enough carb cleaner, or you have a timing, or spark problem.
85's had two fuel pumps. The one in the fuel tank is a low pressure pump and then there's the one on the frame rail that is the high pressure pump. You can't get all the fuel out of them, so if it's been sitting that long, figure on replacing them. Most just replace the frame-mounted pump with another fuel filter, and then replace the in-tank pump with a Walbro that's designed for 87-93 Mustangs. Goes right in. The only issue with that is that there is a resistor inline with the in-tank pump wiring that has to be removed and then the wire spliced back together.
85.5 and 86 I don't think they used dual pumps. 84-85 did, IIRC. Does it have an inline upper intake manifold or a square intake? Inline would be 1984-1985, square ones were 85.5-86.
If in fact that you have to do the in-tank pump, I'd highly suggest looking closely down inside the tank. If you see rust, or the box is loose, replace the fuel tank and also figure on replacing the sending unit while you're there. Don't forget a new pair of grommets-one for the filler neck and the other for the vent valve assembly. Ideally you'd want this stuff on hand so that you don't have to fight it any more than you have to. Been there, done that, many times and I STILL haven't learned.
Similar threads
