Just installed a Pettit stock mount and now I've got a bad idle surge.

700ish to 3000 over and over again.

Is it possible that the IC install would cause the Power FC Idle to get thrown off.
I guess I'm gonna reset it and calibrate the idle again.

Is this an overly common problem found when upgrading with a PFC?

t

 

I'd look for a vacuum leak

 

+1 for the vac leak. I'd also check the TPS.

 

yeah, checked pretty well for vacuum leaks.
Thats the thing that is confusing. While putting in the IC, I was never near ANY vacuum sources that I might have accidentaly fubared.

All vaccuum lines are intact as far as I can tell(unless some random line on the rats nest popped off). I redid all vacuum lines during Christmas.

Car was running perfectly fine. It actually cranked and idled normal after the IC install for about 15 minutes. As soon as I went for a drive, the idle shot up to 3000 and started surging up and down.

So other than vac leak................???


I'm gonna reset my PFC and go from there.

 

ICV gone bad??

 

did you mess with your PFC at all?

Try turning off the O2 sensor see if that works.

 

no, did not mess with PFC at all

turn off o2, or un hook it?

 

I had the exact same problem. May seem stupid but check the map sensor.

 

No not unhook it. I meant turn it off on your PFC.

When I first got my PFC it used to surge like crazy at idle. It wasn't until I turned off the O2 sensor on the PFC that it idled properly. According to my mechanic it was reading values off the sensor and it kept trying to correct itself (hence the surging) so it was a never ending cycle. It literally takes 5 seconds to do this.

Changing your IC should not have any effect on your idle what so ever. So unless you messed with your PFC it shouldn't have happened.

Another thing to try is to start up your car and spray carb fluid all over your vacumm hoses/UIM/ and Lower intake manifold. If the car dies or experiences a change in the idle you've found your leak.


good point. That seems like a likely culprit right there. It's easy to come off expecially when working on the car.

 

why would you want to disable the o2? then you're always running in open loop and it should get even more terrible than stock fuel economy?

also don't spray the carb cleaner on stuff when the engine's hot, kind of a fire hazard, i have no problem doing it to other cars but dang these engines are super duper hot

 

+2

Make sure this is securely in place (might as well zip tie it too). WIth this accidentally off, your car will literally choke and idle roughly big time

 

I explained why. Nope I got better fuel economy than when I had my stock ECU. Close to 400 miles on one tank

 

car is not idleing rough at all. MAP sensor is the first thing I checked.

I have not messed with the PFC sinceI installed it last week and it has been problem free until now.

I have not eliminated the AWS system yet and I am thinking that might be the culprit
(stuck solenoid)
Luckily I live 5 seconds from the man(Dale Clark)so hopefully we will figure it out tomorrow

don't spray carb cleaner on a hot engine?? why not........

 

thanks for all the input

t

 

massive vacuum leak

 

well, i figured it out.
not even gonna tell you what it was

lets just say i'll be praying to the rotary gods tonight for the well being of my motor

 

I want to know, what was it? LOL

 

yah man i wanna know to!!!

 

Don't let pride or whatever keep this thread from being useful....we've all had bad things happen or have done stupid things. Please post the explanation so others can benefit.

And I hope your motor is A-OK.

 

ok then......

cleaned out the IC very well before I installed it. Apparentely it was not enough.
I removed the throttle body inlet to find tiny aluminum scraps were jammed in the throttle plates/ICV.


I pulled off the UIM and cleaned everything out. Recleaned the IC with water/a vacuum/ and gas. I spent 5 hours cleaning the inside of it.
After being almost 100% sure all the **** was flushed out of the IC,
I put it back on and started it up........I got lucky. It runs and idles fine.

Definetely gonna take it easy till i'm sure all this **** is gone.
I'm guessing it was welding shrapnel that got caught in the core.

Moral of the story, always clean the **** out of your IC, no matter how brand new it looks.
Almost cost me a motor.

t

 

might still have, since you drove it. If there was debris caught in the throttle butterfly, then it could mean debris made it through. It would be a TON of work to see if any did.

And what brand IC did you purchase? And where from? I would think cleaning an IC out would be part of quality control by the manufacture.

 

The IC was purchased used. Looks like most of the shavings were aluminum, which is at least soft, and he wasn't rompin' on it when the problem arose.

Glad it's going again, Travis!

Dale

 

Wow, that makes me glad I thoroughly cleaned out my used IC before installing it!

 

so far so good......i'll keep yall posted