Ok guys i just had a clutch installed recently and my mechanic disconnected the battery and since then it has been surging. From 1100 to 1700 rpms but it surges a little higher at times.Recently i brought my car to dave at KDR to have him check it out.He was puzzled also.Since he could not fix it.He tried several tricks.

The first trick he tried was he turned on the car and let it idle and he pressed down on the thermo wax valve and he said if it started to idle right then i needed a new one but it didnt do anything.

Next he tried to adjust the tps sensor.So he started up the car and he let it idle to be fully warmed up and he shut off the car and adjusted the vta 1 and vta 2 on the commander.he adjusted the tps sensor for vta 1 to read 25-45 volts and vta 2 to 85-95 volts and he then restarted it and let it trie to relearn and it still did not relearn.

After all of this the only thing that it did was clean up the idle a little bit it smoothed it out a little but it still surges...

He also suggested that when my mechanic jumped the car he said that he could have put the cables backwards and it would have burnt out the power fc internal mem chip or something like that...

But I have no clue what to do anyone have any other suggestions.. Any help is appreciated..Thanks and sorry for the long post..

 

see if you can borrow an other Power FC... I had a friend last year that had the same problem. If you do not get the surging with another Power FC then your's is probally bad...

best of luck.

 

Try adding extra ground straps to the intake manifold, engine block and negative battery terminal. I had some major surging problems at RPMs lower than 3000, and this helped immensely.

 

The power-fc will make your car surge at light load when it goes into closed loop. Try disabling the O2 sensor from the commander and see if that helps. (No this doesn't hurt anything..) I have run with this unhooked for a good while now.. it's much smoother.. just less MPG.

 

newbernd has a point, mine used to surge going down the road, you could actually watch the injector duty pulsing as i was driving a constant speed. i disabled to o2 function on the prgrammer and it is smooth as silk now

 

Disabling the O2 sensor feedback works well, but it sucks gas unless you have it tuned for partial throttle conditions as well.. my gas milage plummeted when I was testing this.

 

I gladly traded some MPG (wasn't that bad) for getting rid of the damned pulsation.. the closed loop on the power fc is nowhere as smooth as the stock computer.

Funny, I have to put the stock O2 sensor back on now to pass emissions next week.

 

Sorry dave tried that also..He said he tried almost all the tricks him and i were stunned....But I will try it again because it dont hurt.....

thanks guys

 

i tried it again last night and nothing different happened..

 

Does any one else have any clues?

 

^

 

ok would it be safe if i drove on the stock ecu while i send it out to apexi.I have all the bolt ons with a ported motor.Stock injectors though.

Thanks

 

alpha I think you should set the boost to the wastegate spring 7psi just to be safe. You should be ok there but I'm not positive how big the port is and how its going to handle that.

Can someone explain what surging means I've never understood it.

Thanks
Snook