Electrical Ecu not sure a9l crank no start

Creomod

Active Member
Sep 14, 2018
189
18
28
San Antonio,Texas
Still getting crank no start took ecu to altex guy told me it had a hole in the circuit board,funny thing is I don’t remember putting that hole in there and no one has worked on my car and my car was running so do any of you’ll know if “other” then the hole do you think any of these other “issues I see” could cause this in the ecu? Here are some pics. As far as the hole I actually think It’s been running like that so maybe it didn’t penetrate a important part of the ecu?
 

Attachments

  • CC771DDB-4A9E-4529-AF75-35B63D8EDA14.jpeg
    CC771DDB-4A9E-4529-AF75-35B63D8EDA14.jpeg
    698.9 KB · Views: 66
  • AB740C56-37DD-494A-B9E4-27A93B6C11AC.jpeg
    AB740C56-37DD-494A-B9E4-27A93B6C11AC.jpeg
    653.8 KB · Views: 53
  • 585D2276-2183-4136-A5E2-DA7334E227CC.jpeg
    585D2276-2183-4136-A5E2-DA7334E227CC.jpeg
    668.6 KB · Views: 52
  • AEAD2844-E131-4754-8918-4186C8B7E615.jpeg
    AEAD2844-E131-4754-8918-4186C8B7E615.jpeg
    672.3 KB · Views: 48
  • 14DA04C5-B05B-41D5-A652-2F08C3D0C29D.jpeg
    14DA04C5-B05B-41D5-A652-2F08C3D0C29D.jpeg
    478.5 KB · Views: 52
  • BB311838-871F-4095-B857-2309A0D23C00.jpeg
    BB311838-871F-4095-B857-2309A0D23C00.jpeg
    630.5 KB · Views: 51
  • 586932FC-ABB7-489D-90F6-30846A4D15AF.jpeg
    586932FC-ABB7-489D-90F6-30846A4D15AF.jpeg
    632.8 KB · Views: 54
  • 49829A0F-36F0-4D90-9203-3C3BABF93C47.jpeg
    49829A0F-36F0-4D90-9203-3C3BABF93C47.jpeg
    491.4 KB · Views: 59
  • 084D93DD-5939-464B-BC4A-4C57643D5B9A.jpeg
    084D93DD-5939-464B-BC4A-4C57643D5B9A.jpeg
    635.7 KB · Views: 66
  • Wow
Reactions: 1 user
  • Sponsors (?)


jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,513
2,854
234
Dublin GA
Still getting crank no start took ecu to altex guy told me it had a hole in the circuit board,funny thing is I don’t remember putting that hole in there and no one has worked on my car and my car was running so do any of you’ll know if “other” then the hole do you think any of these other “issues I see” could cause this in the ecu? Here are some pics. As far as the hole I actually think It’s been running like that so maybe it didn’t penetrate a important part of the ecu?

Have you done all this checklist and not skipped any steps?

Shortcut: https://www.stangnet.com/mustang-forums/resources/no-crank-checklist.64/

It’s Decision Tree time:

No spark = go to step #1 & 2.
Good spark - what is a good spark can be a subjective judgment. If you have any doubts, borrow a known good coil from another pre 1996 Ford.
If you do have good spark = go to step # 3

Engine fires off and then dies = go to step # 4
Make sure that you have fuel pressure when the engine fires off. Leave the fuel pressure gauge connected while testing so that you can observe what the fuel pressure is doing.

Fuel pressure OK while cranking
Go to step # 5
Be sure to use a noid light to see if the injectors are pulsing. Use the most accessible fuel injector connector for the noid test.

Noid light pulses and fuel pressure is good.
Go to step #6


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 27-Oct-2020 to add need for good PIP signal to keep the fuel pump running after initial 1-3 second prime.

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, fuel pump, and injectors. The computer looks for a continuous stream of PIP pulses to keep the fuel pump constantly running. 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.

attachments\68357


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.



64326




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.
attachments\610738


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.
 

Creomod

Active Member
Sep 14, 2018
189
18
28
San Antonio,Texas
Have you done all this checklist and not skipped any steps?

Shortcut: https://www.stangnet.com/mustang-forums/resources/no-crank-checklist.64/

It’s Decision Tree time:

No spark = go to step #1 & 2.
Good spark - what is a good spark can be a subjective judgment. If you have any doubts, borrow a known good coil from another pre 1996 Ford.
If you do have good spark = go to step # 3

Engine fires off and then dies = go to step # 4
Make sure that you have fuel pressure when the engine fires off. Leave the fuel pressure gauge connected while testing so that you can observe what the fuel pressure is doing.

Fuel pressure OK while cranking
Go to step # 5
Be sure to use a noid light to see if the injectors are pulsing. Use the most accessible fuel injector connector for the noid test.

Noid light pulses and fuel pressure is good.
Go to step #6



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 27-Oct-2020 to add need for good PIP signal to keep the fuel pump running after initial 1-3 second prime.

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, fuel pump, and injectors. The computer looks for a continuous stream of PIP pulses to keep the fuel pump constantly running. 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.

attachments\68357


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.



64326




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.
attachments\610738


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.
I have done ever with exception of spraying starter spray in throttle,I did notice the spark plugs black look fouled out but that’s not o not on the checklist so not sure if that would cause a no start.Another thing I’m checked fuse links but I don’t see the one for the fuel it’s a 92 gt. Ok the fender drivers I see the 3 fuse links that connect to the yellow 10 gauge fuse link wire. I don’t see a orang/blu fuse link I see the black stripe yellow I guess for rear defrost/conv top . Thank you for your response. I have voltage in all right places off the list. I do notice that nss black connector was bridged and the clear one not sure if it was connected to the nss switch. Also pink white wire at ignition switch not connected they ran a wire straight from that spot on switch where the pink/whi wire should be connected to the solonid. It cranks that way but when I run the pink white wire to ignition switch it dosent crank so I just run the eire straight but still no start . Stabbing over and over the dizzy at compression stroke I could hear hiss and I have tdc indincator plus looking at the balancer. Yes I have noid light it blinks have spark tester yes I have spark but someone told me today about spark plugs and I have been cranking over and over. Bought new this past 2 months dynomod distributor,alternator,battery,starter starter solonid alternator power wire inline fuse,act ect sensors, o2 sensors,coil new msd I have another fox a 89 and everything new on there spent lots of money past years on that taking stuff off there to check on this car. Trying to stray it with da1 right now
 
Last edited:

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
39,714
15,492
224
Massachusetts
Your missing a resistor here

BC1F2595-396D-4435-90CE-72F533419235.jpeg




I see a lot of issues with that ECU, including the burned out traces to the heat sink that made that huge hole.

10358520-C649-4970-8F56-89730E9F96FC.jpeg

I don’t think that’s repairable. You might want to source a new ECU
 
  • Like
Reactions: 1 user

rednotch

Founding Member
Aug 14, 2000
516
213
73
south jersey
That ecu is a core only and most probably won't fix it unless they have some good core boards laying around, could try cardone or blue streak. The eec IV doesn't event need to be plugged in to have spark on these cars so you can get them to fire with starting fluid without one... Either way i'd go over the wiring if it nuked the board like that before throwing another computer in.
 
  • Like
Reactions: 2 users

Creomod

Active Member
Sep 14, 2018
189
18
28
San Antonio,Texas
Got it started! Cleaned spark plugs, restabbed distbutor. Car on with da1 it’s a 92 gt. Smoking a lot not sure because cranking so long lots of fuel in there or just because it’s a da1 speed density.
 
  • Like
Reactions: 1 user

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
7,388
3,091
194
Kearney, NE
Got it started! Cleaned spark plugs, restabbed distbutor. Car on with da1 it’s a 92 gt. Smoking a lot not sure because cranking so long lots of fuel in there or just because it’s a da1 speed density.
I’m surprised a speed density computer will run a car set up for MAF. They calculate or measure airflow differently, and look for different sensor inputs.
 
  • Like
Reactions: 1 user

Creomod

Active Member
Sep 14, 2018
189
18
28
San Antonio,Texas
I’m surprised a speed density computer will run a car set up for MAF. They calculate or measure airflow differently, and look for different sensor inputs.
I just disconnected the maf connector and run a vacuum line to the map. I’m the mean time I’m just waiting sent my ecu to ecu exchange they got it today so I’m assuming I’ll have ecu by next week and I’ll try and start the car again
 
  • Ah yes, I see.  I see.
  • Like
Reactions: 1 users

CAMTWO1070

Active Member
Dec 17, 2021
163
48
38
NY
I just disconnected the maf connector and run a vacuum line to the map. I’m the mean time I’m just waiting sent my ecu to ecu exchange they got it today so I’m assuming I’ll have ecu by next week and I’ll try and start the car again
Well the MAP is a Map when it has vacuum and when theres no vacuum line it becomes a BAP to measure barometric pressure......

The only difference I see is that the injectors will be spraying all willy nilly kinda like a hokey batchfire system seeings the firing orders are different....repinning the ECU plug would help but the DA1 is temp and not worth the effort....

IMG_20221023_145334.jpg


Before you install the new ECU make sure you check for 22kohms of resistance between pin #4 on the ECU plug and pin #2 on the TFI module and make sure you have the right module too which is a non ccd TFI module. if you have a 5 speed car..As you can see it doesnt matter the color as they come both ways in gray and black......

If you have an auto you need 0.00kohms at those two points and a CCD type TFI module...

IMG_20221027_201753.jpg

IMG_20221031_000836.jpg

Another thing to do is check and make sure the ground wires for pins #40 and 60 are clean and grounded good to the battery or the unibody by the battery and that your 02 sensors are grounded to the exhaust pipe good with HEGO ground on pin #49 grounded to the intake manifold good too ..

Also its wise to replace the EEC and fuelpump relays with ones with protective diodes aswell as do a continuity test from the ECU plug to all terminations using the proper schematic for your vehicle before replacing the ECU to rule out any barren wires rubbing against each other or a bad terminal in a sensor plug etc... ...

On a friends 89 5.0 we had to rewire the MAF sensor wires by making a new MAF harness w/new plug and removing pins 50 and 9 from the ECU plug and resoldering in the two new wires from the new MAF harness extension and repinning the holes then finding #40 ground wire and tapping the new MAF ground into it also tapping into the old power wire that comes from the EEC relay going to pins #37 and 57..........

My guess is when the old owner replaced the engine he must of mashed the harness or hooked n yanked the MAF wires......He was getting all sorts of codes like 15,33,53,54,66......He sent the computer in and they found issues but not ones that would cause all those issues and the guy at ECU exchange said to do a wiring trace but my friend put the ECU in thinking it was the remedy and low n behold he was getting a different issue...His CEL light was blinking....LOL....


Good Luck
 
Last edited:

Creomod

Active Member
Sep 14, 2018
189
18
28
San Antonio,Texas
Well the MAP is a Map when it has vacuum and when theres no vacuum line it becomes a BAP to measure barometric pressure......

The only difference I see is that the injectors will be spraying all willy nilly kinda like a hokey batchfire system seeings the firing orders are different....repinning the ECU plug would help but the DA1 is temp and not worth the effort....

IMG_20221023_145334.jpg


Before you install the new ECU make sure you check for 22kohms of resistance between pin #4 on the ECU plug and pin #2 on the TFI module and make sure you have the right module too which is a non ccd TFI module. if you have a 5 speed car..As you can see it doesnt matter the color as they come both ways in gray and black......

If you have an auto you need 0.00kohms at those two points and a CCD type TFI module...

IMG_20221027_201753.jpg

IMG_20221031_000836.jpg

Another thing to do is check and make sure the ground wires for pins #40 and 60 are clean and grounded good to the battery or the unibody by the battery and that your 02 sensors are grounded to the exhaust pipe good with HEGO ground on pin #49 grounded to the intake manifold good too ..

Also its wise to replace the EEC and fuelpump relays with ones with protective diodes aswell as do a continuity test from the ECU plug to all terminations using the proper schematic for your vehicle before replacing the ECU to rule out any barren wires rubbing against each other or a bad terminal in a sensor plug etc... ...

On a friends 89 5.0 we had to rewire the MAF sensor wires by making a new MAF harness w/new plug and removing pins 50 and 9 from the ECU plug and resoldering in the two new wires from the new MAF harness extension and repinning the holes then finding #40 ground wire and tapping the new MAF ground into it also tapping into the old power wire that comes from the EEC relay going to pins #37 and 57..........

My guess is when the old owner replaced the engine he must of mashed the harness or hooked n yanked the MAF wires......He was getting all sorts of codes like 15,33,53,54,66......He sent the computer in and they found issues but not ones that would cause all those issues and the guy at ECU exchange said to do a wiring trace but my friend put the ECU in thinking it was the remedy and low n behold he was getting a different issue...His CEL light was blinking....LOL....


Good Luck
Thanks brother! I did get the ecuback from ecu exchange they did a hell of a job. I also got a new dizzy. Cars running smooth and nice. Been driving it for 3 weeks daily. Thank you for the input all information is good to know