5v ref dilema

creeperxr7

Registered User
hey felas hows it been going. i have kinda of a little question here for all u experts. my buddy recently put his brothers sc together after the car had been sitting for about 5 years engine was from a donor car, car is a 1990 auto sc. we made it manual. the prob. is their is a check engine light that wont go away due to the fact that somewhere i have a short between my 5v ref wire and my signal wire in the following sensors.------ tps,baro,etc,atc.... normaly at idle the tps sensor should read around 0.8---0.9v and 4.6v wot. ... not this baby! idle or not it reads 5.0v +.. would any body happen to have an idea of what is the cause to this. thank to all before hand for the help u guis always provide for everyone:)
 
tps,baro,etc,atc

are you saying the all these are maxed out or only the TPS?

Since the TPS is a variable resistor, it also needs ground. Without ground, it will read Vref (+5) all the time.

Vince
 
that would be the orange wire in the injector harness that clamps down to the fuel rail behinde the head right? its on their and that pin is showning continuatiy to ground!:confused:
 
You need to tap the reference ground and not the sensor's ground. Tap the ground to the EEC. I forget what the pin number is off the top of my head.
 
I had that problem, and ended up being a bad TPS, it was constant 5ish, and no changie when you turn it...
 
iv changed the EEC, tps,maf, ect,baro,. if it were to be a short would it be in the o/w ref wire... into the b/w signal wire.
 
You've mentioned additional sensors (MAF, ect, baro) several times now. Are these also maxed out or acting funny?

This makes a big difference to where the problem may be. It is highly unlikely that there would be a short from Vref to all those sensors (unless someone really went to town on the harness). If it's just one acting up, then a short is more of a possibility. :confused:

Let us which sensors are/aren't working.

Vince
 
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