Help!! Stumble/Cut at 5000 RPM

[Purplehazedog]

I just checked the connector on the Firewall. And gaped the CPS to .040...... No luck. A buddy of mine says I should try to swap out the Distributor. What do you guys think?

[FLG]

Did you check the cps gap? And did you check the connector on the firewall I mentioned?

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[ak-]

Swap ECU's with a friend.

edit: whoops. Looks like you tried that.

Check the harmonic balancer to see if it wobbles giving the CPS a bad signal.

[Purplehazedog]

I opened up the C191 connector. It looked perfect?!? (the inside connectors and the wires on the bottom). I added dielectric grease and I still have the problem. Not sure if it is something else, or If I should just replace and solder the wires together just because. I have not idea what to do next.

[saturnv7890]

Might be worth a shot, I had an issue similar and it was the C191. A bad connection causes poor injector performance.

Took me 20 minutes with a soldering iron and all these issues I had been chasing for months disappeared. Might be worth checking out!


If you do it, I'd recommend a 7 pin weather proof connector and some serious dielectric grease, I just soldered all the wires together and bypassed the connector

[FLG]

Yes and yes, too far and you could be fine at lower rpm but start to loose data at high rpm.

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[Purplehazedog]

I did not check the gap on the CPS. .040 right? could that cause this problem?

[FLG]

Did you check the air gap on the cps?

Also might be wise to hook up a fuel pressure gauge and see whats happening at the cutout point.

[Purplehazedog]

Well guys, swapped out the TPS from another car and same issues. I also replaced the crank sensor to no avail. I swapped out the three relays that are on the drivers side next to the strut tower, and nothing.

Could I have a bad Distributor module?

[603Racing]

Do you have an air/fuel ratio gauge in that race car? Fuel pressure gauge? This data would be helpful.

[Purplehazedog]

The AFM was a used one but I had the same problems. So I swapped my old one back in. I've been very busy at work so I plan on working on the car over the next few days.

[jlevie]

When you replaced the AFM, did you replace it with another used one? Or a rebuilt one? Cutting out at specific RPM is a symptom of bad AFM.

That is true below ~4500rpm. Above that the DME no longer uses data from the AFM.

[Gregs///M]

When you replaced the AFM, did you replace it with another used one? Or a rebuilt one? Cutting out at specific RPM is a symptom of bad AFM.

[603Racing]

Jim's probably right. Sounds like a fueling issue (running lean), probably due to the TB not sending the proper signal to the ECU.

[Purplehazedog]

I will check that today, Thank you