1992 LX 5.0 mystery. use to run now doesn't. HELP

voodoo18

Member
Jan 14, 2020
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Western NY
New here. I bought a "car port" find. 1992 LX Summer edition convertible. 5.0 HO Auto. It sat since 2011. Got it home. Got it to run but crappy. Traced it down to the computer. Put in a replacement out of another Fox 5.0. Started right up and ran great. Maybe a miss now and then because of a few sticky parts. It smoothed out after a while. In the process I did a complete tune up. Plugs, cap, rotor, wires. Also did a compression test. Drove it up and down the driveway a couple times and pulled it into a different part of the garage. Did some other work, new passenger side lock actuator, new drivers side quarter window motor, slide bushings and the usual stuff that weir over time. I started it a few times while working on it. Still ran good. I put the top up to aline the windows. After that, I went to start it and all it did turn over. I am a carburetor/points guy. EEC is new to me.
So this is what I have done so far: Changed the cap, rotor, coil wire, fuel filter. I have 35-40 lb of fuel pressure. I went to check to see if I had spark, so I pulled the coil wire off the cap and laid it to the side to check the arc, it started up and ran great. Cool. Then I went to put the wire back on the cap. It stalled. Pull the wire, start. Put the wire back on, it stalls. Checked with one mechanic, he seemed to think that it was the TFI or the PIP. Changed the TFI. Same. Pulled the distributor and changed the PIP. Same. Check the pulse on the coils pulse side, Tan/yellow wire. It pulses. I have 12+ v on the red/L green side. Checked the pulse on the no. 5 injector. Had a pulse. My next step is to check voltage for the ignition system, switch to rely to coil to TFI to PIP and back to the coil and then the computer again.
I guess, after reading the forums and about a million other post and not seeing this problem, my question is, has anybody else had this problem? Another mechanic said that the voltage in and out of the coil and TFI are critical and have to be all of 12+ volts. That is what I am working on now.
 
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General karthief

wonder how much it would cost to ship you a pair
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Pull coil wire out of distributor, it starts. Plug into cap, won't start.
Coil wire is bad or distributor cap?
Check the end of the coil wire and the inside of distributor cap, also the button on the inside of cap. :shrug:
 

08GT500

Active Member
Jul 12, 2018
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Hi,
First, I’d suggest not throwing money at it buying parts someone has hypothesized as bad. Use diagnostics to first prove they are bad.
Am I interpreting this correctly, you pulled the coil wire off the Cap and it ran, reinstalled & it shut down? wth..
You’re getting a fuel pump prime at this point when you turn the Key on?
CPU uses the PIP to trigger fuel injectors. 12V at any Injectors (Red wire). Test with a NOID, turn it over- flashing light, the PIP is ok.
TFI’s generally work or not. Many auto parts stores test for free.
Have the Haynes manual for the Car? There’s diagrams posted if you need them. Can you pls clarify that you didn’t do a type-o, the motors running with no coil wire?
-John
 
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Rdub6

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Hi,
First, I’d suggest not throwing money at it buying parts someone has hypothesized as bad. Use diagnostics to first prove they are bad.
Am I interpreting this correctly, you pulled the coil wire off the Cap and it ran, reinstalled & it shut down? wth..
You’re getting a fuel pump prime at this point when you turn the Key on?
CPU uses the PIP to trigger fuel injectors. 12V at any Injectors (Red wire). Test with a NOID, turn it over- flashing light, the PIP is ok.
TFI’s generally work or not. Many auto parts stores test for free.
Have the Haynes manual for the Car? There’s diagrams posted if you need them. Can you pls clarify that you didn’t do a type-o, the motors running with no coil wire?
-John
Trying to figure that coil wire thing out myself.
 

voodoo18

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Jan 14, 2020
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Western NY
OK. First, thanks for getting back to me. What I have put BACK on the car is known working parts. I had put brand new parts on for the tune up. Rotor, cap, wires, plugs. When it started to give me trouble with he new parts, I put the old parts back on. I bought a new coil, TFI and PIP and installed them. I have checked the volts on the red/L green wire coming into the coil, 12v. The tan/yellow wire maybe 10-11V, I will do this again today. I put a incandescent test light in the t/y wire side when I crank it. It pulses. I haven't checked the voltage on that yet. The red wire going into the injector is 12 v. The other wire, ground, pulses. I have a noid light on order but hasn't gotten here yet.
I put all this stuff together. If I pull the coil wire and lay it on it's side, boot touching the cap post, like testing for spark. The engine starts and runs well with the spark arc coming from the coil wire to the cap post. So I know everything still works. When I go to put the wire back on the cap the engine dies. Moving it almost on, the engine shutters, pull it back so that there is about a 1 in. arc it smoothens out.
To answer the questions, yes, turn the key on, fuel pump primes for 1 - 4 sec. then shuts off. Fuel press. 35 - 40ish. 12v at the red wire on the injectors. As I said, NOID light on order. I do not have a Haynes manual. I have the Ford Manual. No trouble shooting in that book. I have been on line and gotten wire diagrams and suggestions but have never found one where it runs with the coil wire arcing and not when is is not.
So that's my problem. My questions are: What is the voltage suppose to be on the T/y wire side of the coil with KOEO? What is the voltage suppose to be on the T/Y wire side when the KOER? Or just cranking. What are the voltages suppose to be at the TFI plug, I have pins to into the back side of the plugs. What is the voltage on the ground side of the injectors? Maybe I have a bad wire. I think I need to check the ohms next also.
Looks like a have a busy day ahead.
 

jrichker

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OK. First, thanks for getting back to me. What I have put BACK on the car is known working parts. I had put brand new parts on for the tune up. Rotor, cap, wires, plugs. When it started to give me trouble with he new parts, I put the old parts back on. I bought a new coil, TFI and PIP and installed them. I have checked the volts on the red/L green wire coming into the coil, 12v. The tan/yellow wire maybe 10-11V, I will do this again today. I put a incandescent test light in the t/y wire side when I crank it. It pulses. I haven't checked the voltage on that yet. The red wire going into the injector is 12 v. The other wire, ground, pulses. I have a noid light on order but hasn't gotten here yet.
I put all this stuff together. If I pull the coil wire and lay it on it's side, boot touching the cap post, like testing for spark. The engine starts and runs well with the spark arc coming from the coil wire to the cap post. So I know everything still works. When I go to put the wire back on the cap the engine dies. Moving it almost on, the engine shutters, pull it back so that there is about a 1 in. arc it smoothens out.
To answer the questions, yes, turn the key on, fuel pump primes for 1 - 4 sec. then shuts off. Fuel press. 35 - 40ish. 12v at the red wire on the injectors. As I said, NOID light on order. I do not have a Haynes manual. I have the Ford Manual. No trouble shooting in that book. I have been on line and gotten wire diagrams and suggestions but have never found one where it runs with the coil wire arcing and not when is is not.
So that's my problem. My questions are: What is the voltage suppose to be on the T/y wire side of the coil with KOEO? What is the voltage suppose to be on the T/Y wire side when the KOER? Or just cranking. What are the voltages suppose to be at the TFI plug, I have pins to into the back side of the plugs. What is the voltage on the ground side of the injectors? Maybe I have a bad wire. I think I need to check the ohms next also.
Looks like a have a busy day ahead.
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.
View attachment 642143
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.
 
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Olivethefet

Slap me as well as point and laugh
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The checklist above is great. It helped me out a lot when I first got my car.
Have you inspected the connector inside the boot on the coil wire and the connecting point on top of the cap? It sounds like something is keeping it from making contact when you connect the two. Why else would it run when arching into the cap and not when the wire was connected. Just guessing here mind ya.
 
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voodoo18

Member
Jan 14, 2020
29
11
13
Western NY
I have checked all that. Cap, wires, rotors and stuff. I have a DVM and can can check the volts and ohms but I'm not sure of the values or what I am doing is write. I did pull the positive connector on the battery and tested to see if there was a residue flow. Between the pos. terminal and the connector, I have a flow of 6.5 amps. I think that means that something is still on and drawing power. Maybe a short somewhere. I started pulling fuses to trace it but ran out of time. I am going to work on it tonight. I have the above article. I have gone through it before but last night I went through the whole thing again in case I missed something. It's driving me nuts. I think I am going to call in a professional. I have been reading Stangnet for a while but just joined. You guys are great. Thanks for the help.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Just making sure I understand.
you have the same symptoms with new and old cap,rotor and coil wire?
and it ran before the new parts were installed.
 

voodoo18

Member
Jan 14, 2020
29
11
13
Western NY
Yes. Same symptoms.
In somewhat of order. By the way, this is a stock engine. No mods.
To start. pulled plugs. Fogged the cylinders. Turned it over. Fogged again. Put new plugs in. New wires, cap, rotor. Turn the key to run, fuel pump ran constantly.
It did start but ran crappy. Way to much fuel because the Fuel pump ran all the time. Traced it to the computer. Installed a new computer, stock.
Ran beautifully. Started is several times and drove it up and down my driveway. Pulled it back in the garage. Still started. The following may or may not have anything to do with it BUT........ I changed the power lock actuator on the passenger door. Changed the window motor on the drivers side rear. Pulled the other motor, fixed the window slides, then re installed the same motor. I raised the top to aline the windows. Next time I tried to start it, it just turned over. No start.
So, trouble shooting, I have 35 -40 psi fuel pressure after a 3 - 5 second fuel pump prime and then shut off. I checked for spark by pulling the coil wire from the cap. With about a 1" arc from the coil wire to the cap post, the engine started up and ran smooth. As I put the wire back on to the cap, the engine stalled and would not start again until I pulled the wire again. I put another cap, rotor and coil wire on. Same thing. I changed the coil. Same. I changed the TFI. Same thing. I changed the PIP, same thing. So what I have is spark, I have a spark light, from the coil to the cap. I have spark from the cap to the plug. I have fuel pressure. The engine will not start unless I pull the coil wire and let it arc.
I can still make it run if I pull the coil wire and let it arc.
Does this answer your questions.. I am at a loss. I have checked the red wire at the injectors. 12v. I have checked the ground wire at the injector, I don't have a NOID light, I use a test light. I have 12v at the R/G wire on the coil. I have power at the fuel relay. Today I am going to unhook the plug on the computer and check the ground continuity. Maybe the ground is back feeding from someplace else.
So with that said. Any help or suggestions are welcome.
Thanks
 

08GT500

Active Member
Jul 12, 2018
812
113
53
Massachusetts
Hi,
With a 6.5A load, your battery should be dead overnight, has it been low?
Have you pulled any EEC codes? This seems to be an issue affected with resistance values being unusual. Do other vehicle accessories still function?
May be Plug type or gap, wires, connections, a Coil anomaly, Dizzy anomaly, Alternator issue. These can easily be found. Carefully Retrace your steps to see what you’ve done between when the car ran, and when it required the Arc approach to run. Note just because parts are new, it doesn’t mean they function. OE parts are your best bet, aftermarket ignition components are suspect..
Add temporary solid grounds from the Battery’s Neg., the block, EEC, Chassis.
WIRES & CAP:
Measure by length, convert to inches, divide by 12, e.g.:, a 1 ft or 12 inch long wire divided by 12 equals 1, or 1000 ohms per linear foot. That is an average value that works. Check all wires, first check with plugs & wires intact, removed from the Cap. Verify Dizzy is grounded from battery Via VOM.
From a root basic electrical standpoint, application regardless, electricity follows the path of least resistance to ground.
In arc form, It’ll still follow any path desired to ground it “chooses”’, it’s also providing resistance being an arc. unaffected by a ‘short” as iit’s wire is not directly connected.
Once the Coil wire is terminated to the cap, It’s now committed to sending Coil power, even if it intersects with a dead short, it may not provide ample energy to bridge the plug gaps.
Once you physically connect the coil wire to the Coil post, where load(s) exist, amperage now drawn may be large enough to collapse the Coils secondary field, a heavy draw will leave nothing for the Plugs. I suggest waiting on bringing it to a shop, should be able to repair this with assistance here if you stay the course. I do suggest getting a manual..posting a few pic’s of the engine bay & Dizzy with the Cap removed. For now I’d suggest the above & below.
1) Test your wires.
2) Test resistance to ground by pulling the wires from the cap, including Coil, measure resistance to ground.
3) Check your plug Mfg./ID, post.et gaps, little anti seize; reinstall.
4) Remove all wires from the Cap & perform a continuity test from the Coil post to ground. Test the other Cylinders to a ground.
5) Shut off the fuel pump, disconnect or use the inertia switch. Pull all others but (1) plug wire with the Coil connected & see if you have spark while it’s sitting on the block. If OK, try a 2nd plug (all other plug wires disconnected from the cap). If OK, keep moving. Can you get all 8!to fire?
7) Try disconnecting the SPOUT connector, see if it still creates a spark.
8) Try testing both continuity!from the ground post to Dizzy, block, Chassis. Test from Positive terminal to Dizzy & Chassis.
9) At night, Setup an attempt to start the vehicle with the Coil inserted into the Cap, dielectric breakdown & leaks can easily be seen. Try to atart it with the wire partially inserted in the Cap as well.
If you have old wires, compare the resistance values from the new ones. Install if needed.
Good luck!
-John
 
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voodoo18

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Western NY
Thanks for the guidance. I haven't left you. I have been doing grandkid stuff this weekend. However, the other night I pulled the computer. I checked things that have been posted, All the grounds are there. Pin 48, 46, 40, 60. I could not find the eek relay. I think they put it in another car, ha ha. Same thing. Spark, my NOID light still hasn't gotten here yet so I used a LED test light on no. 5 injector and got a pulse on the ground and 12v on the red wire. I checked the coil. Key in run. Got 12v and pulse on the other side while cranking. ( oh side note, I was told that i should test the draw of the system on the - side of the battery. So I check the amps from the - side of the battery to the unhooked connector and there was no draw. ) I tried to start it. Same thing. So I pulled the coil wire like I did before. It tried to start once, backfired through the exhaust. Next, I got a very very weak spark at the coil instead of the big on I usually get. That's when I stopped. Too much frustration leads to bad moves.
I am wondering what would cause a back fire to stop the coil from sending a spark to the cap. When I get back out to my garage I an going to start all over again. Oh, I forgot. I checked the ground to the dizzy, I did it with the wires hooked up. I will take them off and check again. I check the ground from the fire wall to the engine, good. I checked the ground from the battery pigtail and connector to the computer. Good. My fuel pump primes for 1 - 5 sec. when I turn the key on. I have 35 lb. pressure. I think I will the ignition plug and starter for draw when I get at it again.
WIP. I will keep trying thanks to you guys help. Hope you are having a good week end.
 

voodoo18

Member
Jan 14, 2020
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13
Western NY
I think the backfire did something to my module. I put one I had that I know worked and I got spark. Checking wires, I found one under the code reader club that the insulation was crack and broken. The red/green wire that comes from the ignition through a fuse link and then to the coil. After fixing it I try starting the engine with the coil wire on. I still doesn't start. Pulled the coil wire and it did start. Going to work on it tomorrow.
Oh ya, as stupid as I feel saying this, I had the 6 and 8 plug wire switch, that is what cause the back fire.
 

08GT500

Active Member
Jul 12, 2018
812
113
53
Massachusetts
Hi,
You’re making headway, i solidly agree with your comment, I quote: “That's when I stopped. Too much frustration leads to bad moves”. Sometimes it’s best to walk away & reset. I do suggest pulling the EEC’s codes, even without a CE, codes May be found in the EEC. You don’t need a Scantool to retrieve these codes, a 10 Cent paper clip, a pen & pad is all you need.
It’s information, should hear the Computers perspective
Initially, you’d mentioned that the Coil wire was replaced. Cool & plug wires have increased resistance values, to suppress RF signals, mandated by the FCC.
You probably recall older vehicle’s wires ‘buzzing’ correlating to engine RPM’s on radio stations with weak weak, or no reception.
If the fusible link has an intermittent connection it could have something to do with the module, if you look- it’s all connected to the area where you were working, that would collapse the field of the coil once the real load was connected, it also could be related to the TFI module, I’d have it checked at the store, that’s my best guess. I’ll help you, as I’m sure all else will, untilthis coil issue is fixed, shouldn’t collapse under a load unless the feed to it is compromised, or the module itself.
Until then, Best of luck!!
-John
 

08GT500

Active Member
Jul 12, 2018
812
113
53
Massachusetts
Lmao!! AWESOME!! So it WAS that? 6 & 8 reversed created the backfire?
Very cool!
That was timing- huh?
-John
We were typing at the same time...geez- at least let me tell you the issue before you fix it, lol ok!
 

08GT500

Active Member
Jul 12, 2018
812
113
53
Massachusetts
I think the backfire did something to my module. I put one I had that I know worked and I got spark. Checking wires, I found one under the code reader club that the insulation was crack and broken. The red/green wire that comes from the ignition through a fuse link and then to the coil. After fixing it I try starting the engine with the coil wire on. I still doesn't start. Pulled the coil wire and it did start. Going to work on it tomorrow.
Oh ya, as stupid as I feel saying this, I had the 6 and 8 plug wire switch, that is what cause the back fire.
Get an OE part, buy OE if you’re replacing it. Have them test it, if they do. (Most places do) aftermarket parts are “iffy”. Reversing 6 & 8!’s no biggie temporarily, it happens. Did you happen to try the resistance tests from installed dizzy cap to ground, and Coil wire & wire resistance tests?
 
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