al0389

iTrader: (1)

About a 3 weeks ago i cleaned my throttle body with a throttle body cleaner and, well, i flooded my engine because some of the liquid went into the motor. After I unflooded the motor it started to idle irregularly. I searched and found that it may be that my TPS may need adjustment. I Adjusted the TPS according to the thread in the archives and used FC3Spro as a guide as well.

I was able to fix my idle, it sits at 750RPM, from how it was previously idle surging between 1300-1700. Since i stopped the idle surging and fixed the idle, on deceleration it bucks/backfires a lot and my gas mileage has gotten worse as well. It sounds like it backfires through the whole power range, it will pop randomly from 7000RPM to about 2000RPM. Is this from a poorly adjusted TPS or is there something else making this happen. I have an S4 N/A convertible with TII drive train.

Any help would be greatly appreciated.
Thanks
Adam

RotaMan99

Sounds like you have a bad electronic connection between the TPS and the harness. Disconnect the TPS, clean the contacts and plug it back in.

Also sounds as though the TPS is reading to high and the ECU is not shutting the injectors off. This happends if the TPS is unplugged too, atleast with a S4. Seems you have a S5. Make sure the TPS is reading 1v not 1kohm at the TPS plug. Completly different settings. You can back probe the connector or get down at the ECU and read the TPS volts from there.

S4 setups I find need to be set at 1kohm and not 1volt. Don't know why. Seems as though it depends on the TB. S5 TB's are 1v and S4 TBs are 1Kohm. I have played with this many times and found it not to be with the electronics but to be with the TB. Don't ask me why.

al0389

iTrader: (1)

I just checked my TPS again. It was at .5kohm at rest. that may have been the problem. I did my TPS again and set it at ~1kohm it is between .94kohm and 1.1kohm at rest and at WOT it goes to 5.18kohm.


Thanks

al0389

iTrader: (1)

One more question... I just took it for a test drive. The car did not backfire/sputter once and i did take it for a very spirited drive.

I was able to get my idle to sit at 750RPM but the BAC is all the way down, meaning i turned the screw all the way to the bottom until it stopped. Is that normal/ok? I was able to get 750RPM idle with it in a different location but the moment i let go of the gas it will idle at 1000- 1300RPM. and if i pull the throttle body to close it more it will drop it to 750RPM.

Is that normal to have the BAC all the way down?
What would you guys suggest if not?

Sorry for the multiple questions. Thanks...

RotaMan99

I missed in your first post when you said you had a S4 N/A. Opps.

You are adjusting the BACV on a s4 N/A?

The screw you should be adjusting is on the top of the throttle body. If that does not bring it down, check to make sure the thermowax on the back of the TB is extending fully and adjusted correctly. The primary plate should be fully closed when the engine is warmed up so if you are able to lightly force the primary closed a bit, than my guess is the thermowax is holding the primary plate open.

did you remove the throttle body to clean it? If so did you remove the throttle plates?

I forgot to mention but maybe you already knew that you should wait till the engine is fully warmed up before adjusting the TPS.

I didn't think the ECU would leave the injectors on while the TPS volts are below 1v, interesting.

al0389

iTrader: (1)

I thought that the little screw was a BAC, and i did have the car fully warmed up. And when i cleaned it, The Throttle body was still on the car, I took off the piping to the Throttle body, held open the plates and then sprayed it down with throttle body cleaner. My gas pedal was sticking when at rest, and the cleaning did fix the problem...

I was saying that the little screw has to be screwed in all the way down, to get the idle to 750. I wanted to know if that was normal?