BushyTea

iTrader: (4)

Before someone says it I have spent days searching this forum as well as others.

I have a 91 NA Vert and the TPS just will not get to 1.0. Closest I can get is 1.3 and MAYBE 1.28. The screw has been turned all the way in and the spring is fully compressed where it will not turn anymore. I thought it was a bad TPS so I bought one off the boards that was said to be good. Ready is not any different from one TPS to the other either. If I adjust the TPS out then my readings of course go up but the engine runs better when I do.

At times the car will idle right at 750-800 RPM and then other times the car decides it wants to idle between 1000-1500. Sometimes with a bouncing idle and a larger pulse of air out of the exhaust. This is an off and on condition.

So, my question would be is there anything else that can keep the TPS from getting to the needed adjustment of 1.0?

Thanks!

misterstyx69

iTrader: (142)

What the hell is an adjustment of 1.0 ??

st1llet0

iTrader: (2)

Idle needs to be set before TPS.
Make sure thermowax is fully retracting once it's warm.
And he means 1k ohms, the closest he gets is 1.3
You should be able to get it much lower than that, if you manually operate the full range, so it's pressed in all they way, can you get less than 1k ohm resistance?

HAILERS

The engine MUST be fully hot before settingt the TPS. Why? Because there is a item called the waterthermowax that will MOVE the throttle shaft when the engine is cold. When the throttle shaft is moved, that movement effects the plunger of the TPS which in turn changes the output of the TPS to the ECU.

So, if a engine is cold, its reasonable to find out that the output of the TPS can't be gotten below a proper output of 1vdc cause the TPS plunger is NOT where it should be.

So you have to get the engine HOT prior to setting the TPS and the waterthermowax has to be functional.

A properly set TPS will output approx 1vdc on it's narrow range plunger at idle. See the FSM if that is not understood. Section called CONTROL UNIT.

BushyTea

iTrader: (4)

Thanks for the reply guys.

The engine is fully warmed up at the time of these readings.

I have worked on setting the idle many times. Grounded the single green connector and set the idle to 750-800. Its odd because if I start the car and it goes to the proper idle on its own it stays there. Then I can start it at other times and it won't go below 1000. The AWS is working as well.

I did remove the throttle body yesterday and I noticed that the mark on the fast idle cam is not aligned between the marks on the cam roller. I pulled it off when the car was cold after sitting all day as well. I have never had to adjust this part of the throttle body so not sure if that will help with at least the idle issue.

Thanks!

HAILERS

What does the 1 represent that you mention????? 1K ohms or a voltage reading of one volt on the green/red wire? (narrow range)?

Next time you have the throttle body off, pour boiling water over the waterthermowax and make sure the roll pin/ cam seperate doing this. It must seperate for the throttle plates to close all the way.

Turning the TPS screw clockwise causes the output of the TPS to increase. Turning the TPS screw anticlockwise causes the output of the TPS to go down. I'm talking the voltage output with all the connectors connected.

A internal sticking BAC can at times cause the rpms to stay over 1100 rpm. Next time it stays over 1100 rpm and the engine is hot, put the car in gear and slowly let the clutch out a bit to load up the engine and cause its rpm to drop below the high figure. Then put the car in neutral and see if the rpm stays under the high figure or not. Its called a clue.

BushyTea

iTrader: (4)

Yes, it is 1K ohms at the green/red wire.

The throttle body was still off so I did the boiling water trick and the rod looks to have moved alittle bit but not much. Did it a couple of times but never moved much at all.

Thanks!

BushyTea

iTrader: (4)

Well, pulled the thermowax assembly off and I probably wasn't using a big enough pot of water but the rod does extend out just not sure yet how much while on the throttle body yet.

HAILERS

Your looking for the fast idle cam and cam roller to Seperate. As in not touch anymore after the engine heats up.

The green/red wire on the EM harness side of the TPS connector, should read approx 1vdc when the throttle plates are closed and key is ON, engine OFF, or if the engine is at idle. Set your meter to volts dc and backprobe the green/red wire. Adjust to 1vdc with a hot engine.

BushyTea

iTrader: (4)

I never could get them not to touch with what pots of water I had. On the car it moves but as of right now the idle cam and roller are still touching.

However, I did get the TPS down to the 1vdc. There was a clog in one of the ports on the thermowax so it seems that might have helped. I did pull off the plug on the BAC valve and nothing changes. Thinking this may have something to do with the car wanting to die at first when turning on the A/C.

Thanks Hailers

satch

iTrader: (1)

The engine needs to be fully warmed up before removing the BAC to check for a change in engine response. Plus the rpm needs to be below 1100 or so and there also needs to be a load on the engine when removing the BAC plug such as lights on and or A/C on.

Also, to check for a BAC which "might" be stuck open, which can cause a high idle you can pinch off the air hose connected to the BAC with a pair of needle nose pliers when it is idling at a high rpm if the engine is properly warmed up. If the rpm drops to a normal idle then it suggests a stuck open BAC.

BushyTea

iTrader: (4)

The engine is fully warm and the rpms are around 800 now. I had the A/C on max and when I pulled the BAC plug the car died right away.

Thanks!