Renix TPS Low Voltage

Just got a digital multimeter and decided to tackle adjusting my own tps.(I've had the dealer do it previously) I only have 4.64v coming into the sensor.(when optimum is 5 I believe?) I think I read something a while back about someone having a bad ground and thats why the voltage isn't a full 5, maybe? Guy at the parts store said "you must have a bad ECU", but I think thats BS. Can anyone help me out?
Thank ya Thank ya,
Collin

Dunno, mine with the truck not running was 4.74 on the old battery... on the optima, it is 4.86, and with it running, just a hair higher than that.

Mine runs fine now.

I dunno what's too low though.

over2land said:

Dunno, mine with the truck not running was 4.74 on the old battery... on the optima, it is 4.86, and with it running, just a hair higher than that.

Mine runs fine now.

I dunno what's too low though.

Click to expand...

Yeah mine's no higher with the engine running either. If that makes a difference.

that voltsge is ok. you'll never have a full 5 volts

So if my input is 4.64v what do I want my output voltage to be? I'm no good at the calculations. Do I just want it to be .36 volts below what it should be since thats how much the input is below what it should be?

your output voltage should be about 3.85ish, the ideal setting is 83% of the input....usually you measure the input and output voltage (there are numerous threads about this on ) and divide the output voltage by the input voltage to obtain the ratio reading...what transmisssion do you have? I am giving you readings for the aw4 automatic.....

hope this helps a little bit,

Bret S Gray
1990 Laredo XJ

Most of them are in the 4.65 range plus or minus a fraction. Mine seems to shift better at around 86% or around 4.0 volts, out.
Making sure the connectors are clean, a good contact spray helps. And cleaning the grounds at the dipstick holder, will help get true values, that stay the same.
Both sides of the TPS ground through the control units, then to engine ground. There is a resistance in every control unit I´ve tested (in the TPS ground circuit). I believe the resistance was put in the control units, by the engineers for a reason.

Thanks for the help all of you. I figured out that this is one of the simplest things to do on an XJ and all these times I had been taking it to the dealer and spending 40 bucks a time. Oh well, ya live and learn I guess.