Engine 93 Cobra loses spark>>>>

Monkeybutt2000

Advanced Member
Aug 11, 2019
393
278
73
49
Lafayette,IN
Owner (very close friend) has been battling this issue for over a year. Car will start and run for about 20secs,then die. With the key in the ON position, you pull a plug wire and put a plug in, it will NOT spark. You cycle the key back to OFF, the car will start,or throw spark at said plug EVERY time. If you pull the plug from the TFI module,and plug it back in, it will start or throw spark as well. There are no aftermarket electrical items hooked up to the car. We have tried two different ecu's, two different coils, and two different distributors. All three of these items were from my running,driving car so we know these parts are good. If you hook a dvm to the coil,and turn the car over,you can watch the voltage drop. We pulled codes as well, but IMO they wouldn't cause this issue. I can post those later if necessary. So,where do we begin?
 
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Monkeybutt2000

Advanced Member
Aug 11, 2019
393
278
73
49
Lafayette,IN
IMG_20200920_163057958.jpg
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,610
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Massachusetts
When you lose spark, do you also lose fuel injector pulse? Can you test with a noid light?

If not, I would troubleshoot the ECU relay, or just try swapping it if it's easier since you have a car to "borrow" one from. Not 100% sure this is a valid reason for your issues, but one thing to check out. It would be good to know if you are just losing spark, or losing injector pulse as well at the same time.
 

Monkeybutt2000

Advanced Member
Aug 11, 2019
393
278
73
49
Lafayette,IN
When you lose spark, do you also lose fuel injector pulse? Can you test with a noid light?

If not, I would troubleshoot the ECU relay, or just try swapping it if it's easier since you have a car to "borrow" one from. Not 100% sure this is a valid reason for your issues, but one thing to check out. It would be good to know if you are just losing spark, or losing injector pulse as well at the same time.
Gonna pick up a noid light,won't hurt to have it around. EEC relay was replaced with a parts store unit.
 

nickyb

WAIT,you now have a pair?
5 Year Member
Apr 3, 2009
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nevada
To me it doesn't seem like a part because you have replaced with known good ones.I believe it's a wire or wire connector.start with coil connector/wires.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,610
9,900
224
Massachusetts
If I solve it, can I have the cobra?

Seriously, I am curious if you lose injector pulse and spark at the same time. Could potentially narrow down where in the wiring the issue might lie.