Today, I adjusted my idle and TPS. The car idled and ran great. Came home let the car cool off for only a little bit... Started the car back up and had to readjust the idle. Then shut the car off (key on) and readjusted the TPS.

Why does it seem that I have to readjust the idle and TPS every time after a hot start?

What kind of information are you guys going to need? I am stumped on this...

 

I've been searching and searching... read tons of information, and figure that I think I need to check the dashpot, hunt for ANY vacuum leaks, and adjust the TPS a bit more. I know this all has been covered plenty of times before... I was just seeing if anyone had experienced this particular situation.

And from what I've read... They're all pretty similar.

 

set the TPS with the car fully warmed up

 

That's what I've been doing. I drive the car for about 35-40 minutes, and then set the TPS.

 

bad tps?

 

What exactly makes you think the TPS is out of adjustment? How are you setting the TPS?

According to the FSM a properly set TPS will output approx 1vdc when the engine is fully warmed up. Can you check this yourself?

A cold TPS will output a different voltage than a fully warmed up on. Its not the idea of the TPS getting hot or cold but the idea of the water in the engine being cold or hot. IF cold, the throttle linkage will be moved by the waterthermowax device and this movement will cause the throttle plates to crack open just a touch thereby effecting the idle.

As the water heats up the waterthermowax gets seperated from the throttle linkage and the throttle plates close fully at idle now.

The waterthermowax also causes the TPS's plunger to move prior to the water getting fully warm. It's the waterthermowax moving the linkage that causes the plunger to move.

IF the water temp is 50* the TPS will not be outputting the same voltage as when the water temp is 180*. Anything that moves the throttle linkage causes the TPS output to change one way or the other.

 

initial set coupler being used when adjusting the TPS?

 

--->I have been setting the TPS according to the FSM.<--- The first time I ever set it was yesterday. It WAS off. I set it about three different times... Each time after driving the car anywhere from 35-40 minutes. Are you saying that once the engine warms up, (idle has been set and TPS adjusted PRIOR), the idle will return to a 'normal' idle? Therefore, no need to adjust TPS, idle, etc... again?

 

There could be other contributing factors but I think what Hailers is getting at is check the TPS after the car is fully warmed up and compare it to the previous setting such as "it was 1 volt when previously set after the car was warmed up and when I use the car again what does the TPS read after the car is warmed up once again." Are the readings the same or not? If it varies by a fair amount then possibly the adjusting screw is too loose and changes position from engine vibration. There are a number of these cars on the street which idles perfectly after warm up but bounces around until that point is reached.

 

Alright. Is there a way to "lock" that adjusting screw? I want it to stay in place, but don't want it to permanently be in that position. (In case it needs to be adjusted.)

 

You need to first verify that the voltage reading is changing before you go about finding a solution to the problem so compare apples to apples and see if the readings change or not from each other when comparing a warm engine versus a warm engine.

 

Earlier, I had a chance to check the TPS after driving it to full operating temperature. It read 1.026 - I adjusted it to 1.000

I realize that extra .026 is no big deal. What I noticed is that my idle is very jumpy at first. When it gets to full operating temperature, it idles just fine anywhere from 950-1,050 RPMs. I figured the higher idle is due to modifications and mild street port of the engine.

 

Post above.
This is what you are saying.

 

Yep.

 

Mine reads way up past 1.50 when cold, but once its warming up you can watch the Volts drop down slowly and stop at 1v once warm.
Hook up the meter right after you start it, watch it while it warms up and it should drop. Dont drive it, just warm it up at idle to full temp. It usually takes my car at least 5 full minutes but I do it until it until the volts stop moving. Should be steady once warm.

 

I can set mine to say 0.95vdc or set it to 1.10vdc and there's no difference in the idle etc.

Yes. the .026vdc diff is of no significance at all. None.

A cold engine in the winter/fall may read something similar to 15. to 2vdc or even three volts if cold enough, but as the engine warms up the volts go down and when the engine is fully hot the TPS will read approx 1vdc. Normal as can be thing. Its the water thermowax/fast idle cam/roll pin that make the TPS plunger move and read other than one volt dc at idle. Anything that moves the throttle linkage will make the TPS read different.

I can set the TPS using the two LED light method or just monitoring the voltage output of the TPS as I screw the TPS screw. The end result is always.....approx 1vdc.

Even using the two LED light method will give slightly different results depending on which way you have to turn the screw to get just one of the LED's lit up. Like if you have both LED lit up you can turn one way to get only one LED and the voltage output might be 1.10 vdc. Then if you go mess with it once more and have two LED's lit up and have to turn the screw the opposite way you did prior to this......the volage output might be .95vdc. Normal operation and adjustment imho. I opt for setting it looking at the voltage output with a fully hot engine and engine idling. It's easier for me.

I never set the initial set coupler when doing so. Found out it matters not. IF setting the idle speed its worth jumpering the initial set coupler. What that does is NULL out the BAC so it won't respond to your adjustmets you making with the idle screw. There's no ECU memory involved here whatsoever. This ECU has close to no memory...humor.

The TPS tells the ECU what Zone of operation the car is being driven in, a small turn of the screw does not make the ECU spurt more or less fuel into the chambers

 

I'm gonna say stuck thermowax if you're constantly adjusting the tps.