Coupe problems!

[91CoupeMike]

Ok so remember the thread about my car dying at high rpm? Well it did it again yesterday but it was closer to 4500rpm when if happened.

Had an older man playing around with me Yesterday in a 4eye hatch, super clean, I went to get on it in 2nd and it was running with slight hesitation and then it just dies and comes back on. But this time it was running like a complete dog after it came on. My AFR is normally around 14:1 and it was at 11:1 while this was happening. Figured maybe the FPR vacuum hose may have came off so I pulled over to investigate. Found nothing that jumped out at me.

Turned the car back on, and it was running great after that. So I'm thinking its electrical or computer related.

Any ideas? It felt like it had lost timing when it was running like shit.

[86lxttop]

loose fuel pump relay connection?

[ktm300hater]

Do you have another regulator to try. That's where I'd start

[bird_dog0347]

I'm gonna say either fuel or spark... what's your ignition system and fuel system setups?

[Diabolic]

Mike I think it's computer related. Sometimes when I would hit a large pot hole in my Cobra with the QH installed it would cut out for a split second then the AFR's would drop into the low 11's before adaptive learning of closed loop would come back into play and bring it back to stoich. It did this many times before I swapped the ecm. After that it never happened again. It was like the key was turned off and back on so the ecm came back online and had to go through the warm up etc......so it would go into open loop. In the datalogs even the tps signal and timing would fall to 0 for a split second.

[91CoupeMike]

Stock ignition with msd coil. Stock fuel system with Holley 255 pump and 24# injectors.

I don't understand the hesitation and then running rich and low on power, turn the car off and back on and it was back to normal.

Could it be something not getting enough power?

[91CoupeMike]

Mike I think it's computer related. Sometimes when I would hit a large pot hole in my Cobra with the QH installed it would cut out for a split second then the AFR's would drop into the low 11's before adaptive learning of closed loop would come back into play and bring it back to stoich. It did this many times before I swapped the ecm. After that it never happened again. It was like the key was turned off and back on so the ecm came back online and had to go through the warm up etc......so it would go into open loop. In the datalogs even the tps signal and timing would fall to 0 for a split second.

That sounds accurate. So you think the computer could be moving around or just that's its going out? Can I take my chip out bad put it on my a9l, I have a a9p now. Would that effect the tune, no?

[Diabolic]

Will it run without the tune? Was the injector size changed in the tune? In hind site I think it was probably the QH connection and not the ECM. We put the first ecm in a friends car and he hasn't had any issues.

[91CoupeMike]

Will it run without the tune? Was the injector size changed in the tune? In hind site I think it was probably the QH connection and not the ECM. We put the first ecm in a friends car and he hasn't had any issues.

Ill pull the kick panel and take a look.

It will run without the tune, but I'm not so sure how it will like the Lmaf and 24s, I only pulled in into the shop w/o tune, idle.

Andy tuned it, and he asked what all I had so im sure the injector size was put in there.

[bird_dog0347]

Stock ignition with msd coil. Stock fuel system with Holley 255 pump and 24# injectors.

I don't understand the hesitation and then running rich and low on power, turn the car off and back on and it was back to normal.

Could it be something not getting enough power?

Hmm... have you checked all your ground connections?

[DriveWayBuilt]

You may need to run bigger wires to your fuel pump, Could be dropping voltage. Samething was happening to a friends car.

[0393gt]

I think if you are using an a9p in place of an a9l there are a few things that have to be changed for it work correctly. I read that somewhere

[91CoupeMike]

I think if you are using an a9p in place of an a9l there are a few things that have to be changed for it work correctly. I read that somewhere

It's been like this for about 4 years with the a9p.

It been acting up recently.

[redrocket5.0]

I had a TFI module going in and out on me. It did the same thing you're describing.

[91CoupeMike]

I had a TFI module going in and out on me. It did the same thing you're describing.

I have always heard to keep one in the glovebox just in case.

In my 10 years of fox body ownership, I've never needed one.

But it would make sense as well.