does my tps % show around 25% when I am actually at 90-100%? Has anybody ever had this problem?

 

hi

a friend of mine had a similar problem on his 1989 corvette...

TPS stuck at 1,2xx volt, regardless of TPS position..turned out to be the ECM...

otherwise..check the TPS if resistance(disconnected) or Voltage(connected) goes smooth with opening

 

With a voltmeter hooked up I get 4.06V @ WOT and at the same time the scantool/laptop show 1.35V and 13% throttle position. closed throttle shows .62 volts...ECM???

 

Are you measuring that voltage at the sensor output or ECM input? If your measuring the sensor output measure it also at the ECM input, if the voltages look good there try cycling the connector (unplug and plug back in) if the reported voltage is still low it probably is a bad ECM.

Good luck-

Paul T.

 

Thats what I did...just narrowed it down to the ecm. Borrowed one from my little bro and it solved it. The car is a whole new animal now!
Thanks guys!

 

hi!!

glad you found it...just want to add another note....

i looked at my recorded datamaster files, and fount the TPS volts stucked at 1.37Volts..pretty the same, you observed..htis was the ´165 ECM on the 1989 Vette..

interesting, isn´t it?

 

Wow! that is a little strange. They must share some common citrcuitry. I did notice if I smacked the ecm it would read what it was supposed to. I am suspecting a bad solder joint, but since these circuit boards are epoxied there really isn't much I can do to fix it.

 

If th ECM is the '730 as for your '91, it is a conformal coating. Easy to remove with some thing such as BrakeKleen (acetone, toluene, goof-off, etc).. Can even solder through it if needed.

RBob.

 

Good to know. Yeah it is the 730 from my 91. I will look into it...now if I can only find the culprit.

 

not an expert but I would trace the ciruicts for all the tps pins....

 

that is what i will do tomorrow...i will let you know what came out