I think iīve got a problem with my TPS ?! In idle, the voltage is 0,56 V. Thatīs Ok. The car runs very well. But in WOT, Iīve just got the voltage 4,32 V.

I think, it should be 5 V ?!

Can you help me ? Whatīs the right voltage in WOT ???

 

The 4,32 volts at WOT isn't too far off. The TPS won't, and shouldn't, go to 5,0 volts at WOT.

First thing to check is that the throttle is actually going against the stop on the TBI. Floor mats are an issue which will prevent true WOT.

If you open the TBI by hand at the TBI unit, you will note that there is a stop. This is true WOT. Now go around to the drivers door and reach in with your foot and press the go-pedal. While doing this watch the TBI and see if it goes to the stop.

If not then need to check the floor mat. Sometimes need to remove padding from under the carpet.

RBob.

 

Thatīs Ok. I pushed the lever on the TPS directly and I opened the TBI by hand. Itīs the same. I think, iīll buy a new TPS.

 

is that something the computer handles and keeps it down?

 

Not really, the ECM only reports what the sensor sends to it (as a voltage).

One reason that the TPS voltage is never supposed to be at 0 or at 5 volts is that they are the ends of the possible range. Which are used for diagnostic purposes.

If the ECM reads 0 volts from the TPS, then it knows that something is wrong with the reading. Same for 5 volts. Something is not correct. One will throw a code 21, the other a code 22.

OBD originated from GM ECMs. Which really do help. Nothing worse then having a bad sensor that the ECM doesn't know is bad. Note that the on board diagnostics also pick up items such as disconnected sensors, and open or shorted sensor wiring.

GM also has code that will create default values for some sensors. This can be good enough that it is hard to tell that you have lost one (other then the SES light).

RBob.

 

What would be the benefit,if any, with having tps set to 0.70 at idle? Mine is there and at WOT it hits 4.31 V Max.

 

Doesn't matter. As long as the TPS is between something like 0.2 V and 0.9 V it will work. The ECM auto-zero's the TPS to provide 0% TPS at idle.

One thing that I do like to set up is the TPS% gain. This calibration parameter is used to convert the voltage to a percentage. Set it so that WOT just gives 100% (TPS%).

Note for others that are not TBI, the MAF TPI ECMs are different. They must be set to 0.54 volts to work correctly.

'90-'92 TPI cars and the '90-'91 MPFI cars are in the same auto-zero category as the TBI cars.

Don't know about the early MPFI cars.

RBob.