so i just got done putting a TPI 305 from an 89 trans am into an 85 trans am.. it ran good for a few days.... I went out and tried to start it a couple hours ago and it would start for about 1 second and die... I couldn't even keep it runin' with my foot pegged on the gas, it was like i wasn't even pressing it. so i checked for codes...and came up with code 22... tps signal voltage low... i pulled the connector off the tps and there was a bunch of water in it... i hooked up the blower nozzle to the compressor and dried it off... tried to start it and same thing happend....

does this mean the tps is fried?

also.. in the manual for my code reader it says fuel cutoff relay circuit -open or shorted to ground... umm... does this apply to me?

thanks :-)

 

If you "dried" the TPS with compressed air, you may have only driven the water into the TPS instead of driving it out.

Put down your code reader, and pick up your voltmeter. Test the TPS output voltage through the entire throttle range (key on, engine off). You should be able to read 0.5V at idle, and 5.0V at WOT. The voltage output transition from idle to wide open should be smooth and steady as you operate the throttle.

 

where do i put the volt meter?

 

so, i replaced the TPS and it still won't start... earased the codes and it doesn't come back.... so... any ideas for what else could be the problem? ... what's this fuel cutoff relay all about for the code 22?
...and i was never able to test it with the volt meter because i'm not sure where to put it... i stuck it in the connector when it was disconnected and got 5 volts... but i'm not sure how to test it when it's connected...
thanks
jordon

 

One terminal should always be +5V with the key on. Another should be ground and the last will sweep somewhere between 0.42V and 4.5V as you turn the TPS input shaft. Note that you must have the key in RUN before measuring the voltage.

I had a problem with mine once upon a time. It was a bad TPS and a bad TPS ground.

 

where does the TPS ground? and how do i measure the voltage of the TPS when it's connected so i can see if the voltage changes properly? and has anyone ever had the TPS make it so their car wouldn't start?

thanks

 

Just place the meter's negative to the battery - and probe for voltage on each of the three wires attached to the TPS. One (the ground) will give 0V, another (the reference signal) wil give +5V and the last one will sweep from roughly 0.5V with the TPS closed to about +4.5V with it fully open. Slowly run the TPS through it's full range a few times. If the voltage jumps around instead of gradually increasing/decreasing then you've got a bad sensor.

Hint: when probing these types of things, I soldered a needle onto the end of a wire. Push the needle through the insulation to probe.

Most, if not all, of the engine sensors ground out via crimp terminals to the back of the cylinder heads. After a decade or two, these connectors get weak and/or break off causing little electrical problems such as these. For any other sensors that are acting strange make certain they have a good ground