final diagnosis: Ig Control Module

[allballsmustang]

a few months back i started having a problem with my car cuting up at full throttle that i posted about... just thought I would share my final results because I found them a little odd and it may help someone else in the future. The car was not displaying any check engine light(it does function) and also the only code i got was an egr code(because my sct chip has the egr turned off). My original suspects were the obvious plugs, wires, cap rotor. None helped. Then I started checking sensors Mass air, act, coolant temp, tps, iac, oxygen sens, all seemed ok. Then I tried something on a complete guess and it worked. It was the ignition control module. I had replaced it a year and a half ago but i guess it was failing already. The car would only cut up when it was hot so im guessing that the internal circuitry of the ig control module "opened" when it was getting hot causing the miss. Never got a cylinder misfire. Strange, I'm glad it's fixed but just a little curious why I didn't have any codes pointing to ignition problems. Anyone?

Jim

 

[HISSIN50]

Generally the TFI's do show failures when hot (the critical temp threshold is 257*F, and this goes down if the module is degrading).

The IDM can't always pick up issues, especially relatively conditional ones like this, and if the failure was on the input side of the TFI, the IDM might not pick it up anyhow.

Nice work figuring it out.

 

[1990lx5oh]

When my ICM went out, i was stranded, it completely shut down, until it cooled down a little bit then ran for 15-20 miles or so. The bad thing was I was in the middle of a local "Pony Run" and had to watch 150 or so Stangs pass me by...little embarassing... That was a good guess though!!

 

[cenok is family]

do you guys think the ign con mod could cause my car to spit and sputter?

 

[allballsmustang]

what are the symptoms...

 

[cenok is family]

no problems other than she's kinda spittin at me. still runs hard at WOT but i can tell the spitting and sputting is slowin her down a bit. she idles fine. only really does it under normal acceleration. i guess it could be miss firing? absolutely everything on my motor is brand new aside from my MAP sensor. new ACT, ECT, MAF, IAC, EGR vac solenoid, less than 1k on motorcraft plugs, taylor wires, less than 20 miles on cap, rotor, coil. the only thing i can think of is i ran through a pretty deep puddle and got some stuff wet. i don't recall it doing it until that. that's when i replaced the cap, rotor and coil. the ICN was replaced a couple years back. i'm thinking maybe it got wet but from what i understand, they either work or don't, and typically when they go bad, they start causing your car to die while driving which my car doesn't do.

 

[68stang351]

This is exactly why my 90 has a spare ignition module and tool in the glove box AT ALL TIMES!

 

[allballsmustang]

its a good possibility considering mine only lasted about 10,000 miles and started going on me...

 

[rich1]

a few months back i started having a problem with my car cuting up at full throttle that i posted about... just thought I would share my final results because I found them a little odd and it may help someone else in the future. The car was not displaying any check engine light(it does function) and also the only code i got was an egr code(because my sct chip has the egr turned off). My original suspects were the obvious plugs, wires, cap rotor. None helped. Then I started checking sensors Mass air, act, coolant temp, tps, iac, oxygen sens, all seemed ok. Then I tried something on a complete guess and it worked. It was the ignition control module. I had replaced it a year and a half ago but i guess it was failing already. The car would only cut up when it was hot so im guessing that the internal circuitry of the ig control module "opened" when it was getting hot causing the miss. Never got a cylinder misfire. Strange, I'm glad it's fixed but just a little curious why I didn't have any codes pointing to ignition problems. Anyone?

Jim

Common well known problem in the 5.0 if shutting off of acting up when hot. I have a tester for them but easier to just replace it .

 

[allballsmustang]

Common well known problem in the 5.0 if shutting off of acting up when hot. I have a tester for them but easier to just replace it .

how did you test it? where can you get one of these testers?

thanks

jim

 

[68stang351]

how did you test it? where can you get one of these testers?

thanks

jim

Any Autozone can test it for free.

 

[cenok is family]

Any Autozone can test it for free.

lol i work at autozone, i just need to quit being lazy and take it in to work one day.