I screwed up...Need some help

[DeMoN2318]

I had been fighting with getting my TPS set correctly for the past few days and last night I bought an analog multimeter and finally got it dialed in.

I first set the throttle stop screw so that the throttle gap was 0.0015'', I then slowly rotated the TPS until it deflected and tightened it down. I checked the TPS per the TSRM and all the specs checked out. I then disconnected the battery and pulled the ECU fuse for 30 seconds.

Now the trouble...I started the car and it was idling high...around 1500 rpm. I let the car warm up and the idle did not come back down. During a moment of poor judgment I grabbed a screw driver and started to turn the idle screw on the throttle body...the idle started to come down but the screw bottomed out before the idle got to where I wanted...only got down to 1000 rpm.

Frustrated...I stopped for the night. Got online and started searching the forums about high idle and adjusting idle etc etc and to my horror nearly every thread said DO NOT ADJUST THE IDLE SCREW ON THE THROTTLE BODY.

So I search through the TSRM but could not find anything about adjusting the idle screw or what it should be set to.

So my question is...does anyone know where the idle screw should be set to? Preferably how many counterclockwise turns from fully closed should it be?


Through my searching I discovered that I should first check the ISC valve and search for vacuum leaks to try to address the high idle issue...not use the idle screw

Thanks for any and all input!!

 

[IndigoMKII]

Okay, just wait.

Whenever you move the TPS, you need to recheck your static timing with t1/e1 jumped.

When I adjusted my TPS but didn't reset my static timing, I was running near 0 degrees timing.

 

[hvyman]

That screw is set from the factory. Its why 89+ have it blocked off.

Is the timing set at 10?

 

[jetjock]

...Whenever you move the TPS, you need to recheck your static timing with t1/e1 jumped...

Huh? Not true. The TPS needs to be set right to adjust timing but that's not the same thing.



OP: It should be set fully closed. Remember, the idle in this engine is automatically controlled.

The proper sequence for setting the TPS/TB/timing is:

1) Disconnect linkage/rod

2) Set throttle plate just fully closed using the stop screw.

3) Reconnect linkage/rod. If it opens the plate, adjust linkage.

4) Set IDL contact in TPS. Although it works an analog meter is not required.

5) Set dashpot.

6) Warm up the engine and enter diag mode.

7) Check for no codes, especially no code 51.

8) Check and adjust ignition timing as needed.

Again, you seem confused about how this EFI system works. Induction leaks will not result in high idle.

 

[MightyAl]

Huh? Not true. The TPS needs to be set right to adjust timing but that's not the same thing.



OP: It should be set fully closed. Remember, the idle in this engine is automatically controlled.

The proper sequence for setting the TPS/TB/timing is:

1) Disconnect linkage/rod

2) Set throttle plate just fully closed using the stop screw.

3) Reconnect linkage/rod. If it opens the plate, adjust linkage.

4) Set IDL contact in TPS. Although it works an analog meter is not required.

5) Set dashpot.

6) Warm up the engine and enter diag mode.

7) Check for no codes, especially no code 51.

8) Check and adjust ignition timing as needed.

Again, you seem confused about how this EFI system works. Induction leaks will not result in high idle.

I would say these 2 steps are critical. Make sure your linkage is not opening up your throttle body. I fought idle problems for a month until I checked the linkage. It was opening the throttle plate causing all kinds of problems.

 

[DeMoN2318]

Huh? Not true. The TPS needs to be set right to adjust timing but that's not the same thing.



OP: It should be set fully closed. Remember, the idle in this engine is automatically controlled.

The proper sequence for setting the TPS/TB/timing is:

1) Disconnect linkage/rod

2) Set throttle plate just fully closed using the stop screw.

3) Reconnect linkage/rod. If it opens the plate, adjust linkage.

4) Set IDL contact in TPS. Although it works an analog meter is not required.

5) Set dashpot.

6) Warm up the engine and enter diag mode.

7) Check for no codes, especially no code 51.

8) Check and adjust ignition timing as needed.

Again, you seem confused about how this EFI system works. Induction leaks will not result in high idle.

Wonderful! Thanks a bunch! I will do this tonight!

I did not think to remove the linkage...dohh

Where is a good place to learn how the EFI system works?

 

[IndigoMKII]

Huh? Not true. The TPS needs to be set right to adjust timing but that's not the same thing.



OP: It should be set fully closed. Remember, the idle in this engine is automatically controlled.

The proper sequence for setting the TPS/TB/timing is:

1) Disconnect linkage/rod

2) Set throttle plate just fully closed using the stop screw.

3) Reconnect linkage/rod. If it opens the plate, adjust linkage.

4) Set IDL contact in TPS. Although it works an analog meter is not required.

5) Set dashpot.

6) Warm up the engine and enter diag mode.

7) Check for no codes, especially no code 51.

8) Check and adjust ignition timing as needed.

Again, you seem confused about how this EFI system works. Induction leaks will not result in high idle.

Okay so I'll rephrase it. Whenever trying to time an engine, the TPS needs to be set properly.

 

[jetjock]

^ There ya go.

OP: The TSRM and tech articles on autoshop101.com are good places to start.

 

[DeMoN2318]

Ok I followed the above steps and it idles fantastic!

But i am still getting a weird kind of miss...I was looking through the TSRM and it seems to be the emissions fuel cut. To test...the TSRM says disconnect the tps plug then slowly raise the rpm...fuel will cut at 1800 and come back on at 1200. That is exactly what is happening except my tps plug is still connected...is this normal? maybe I have a broken wire in the harness?

My tps clip is broken but it seems to connect securely...

Seems odd its exactky the emissions fuel cut

 

[jetjock]

Than the TPS still isn't right.

Do you get a code 51 with the pedal depressed? With the throttle slightly open?

If so that's normal and the TPS isn't at fault. If not the TPS needs to be set properly or there is a *short* in the wiring.

 

[nrdriver]

ive also had the exact same thing happen with pcv vacume hose leaks

 

[Backlash2032]

Basically the TPS is sending out the IDL signal, so the ECU thinks the TPS is closed, yet the AFM is saying the engine is sucking more fuel than it would at idle, so the ECU cuts fuel. So either the IDL wire is shorting out, OR the TPS is not set right.