GTA88

I adjusted my tps idle tonight to .50 approx, and during my testing, the lower jumper wire fell out, leaving the voltmeter probe in the middle socket of the tps, and the top jumper wire still intact. I noticed that this setup put the voltmeter exactly at 4.0 Volts. I have read that the 'reference voltage' is supposed to be 5.0 V, so what is this 4.0 V reading ? BTW, my wot reading is 4.0 V, too. Maybe that setup pins it at the wot voltage ?

How do I test the 5V reference voltage with the jumper wire method? Tired of poring over the archives.

Thanks


------------------
88 GTA Charcoal Grey Bone Stock except for loose muffler which makes it a bit louder than normal.

Aaron91RS

iTrader: (2)

This it how it works on my RS but I assume its the same for you.

White wire should have constant 5 volts going through it. Blue will change as your TPS postion changes. Black is a common ground.

Anything reading over 4v from the blue wire is WOT to the computer.

8Mike9

May want to check the TPS ground for clean, shiny contact, also check the grounds at the rear of the heads for the same.

GTA88

There are only 3 wires going into the tps. All the contacts on them are clean. What do you mean by tps ground ?
As far as the grounds behind the head, do you mean the wires that are screwed into the firewall ?



------------------
88 GTA Charcoal Grey Bone Stock except for loose muffler which makes it a bit louder than normal.

8Mike9

Yes, the TpS ground I was referring to was at the pins, it was late last night The grounds for ECM signals are are attached to the rear of the heads, you'll see 3-5 black wires connected to ring lug terminals. Not on the firewall, but in the rear of each head.

8Mike9

I must still be snoozing there is a firewall ground strap on the pass. side (on my IROC), that I believe connects to the rear of the pass side head, it too should have a clean connection on both ends.

GTA88

Yeah, Mike, I've looked back there, leaning way over, even with a flashlight, can't even see the back of the heads, let alone what's attached to them. Do you have to use a mirror, or jack the car up to see back there ?




------------------
88 GTA Charcoal Grey Bone Stock except for loose muffler which makes it a bit louder than normal.

8Mike9

I can see mine w/the hood open, leaning in kinda from the side.

Hope I'm not steering you worng, but I'm sure the Pontiacs have them where the Chevy's are.

Just for grins, maybe post up a new Q..."Where are the ECM grounds on an '88 GTA".

Might be different, I know you guys have the battery and charcoal cannister on the wrong side

Guest

85, 86, and 87 have them in the same spot as on a Camaro. No reason to change it really on later ones.

Feel around behind the head, down at the bottom of the valve cover towards the outside of the car, thats where the grounds hook up.

GTA88

OK, I snaked my hand way back around the a.i.r. tubes on the driver's side, in behind the head, and felt a lot of different stuff. Got my hand caught back there like a rat stuck in a trap for a good 60 seconds and rediscovered my claustrophobia for a while. With a flashlight I could see a loom of wires going into some apparatus right on the block under the valve cover, drivers side, but it didn't look like ground wires.
Now on the passenger side I saw a definite ground wire, the braided kind, locked sown on the block with a big bolt. The bolt and the washer looked pretty clean, but the braided wire, which I guess was silver befire, is now a bluish green color. I suppose that's OK. This braided wire went up to the firewall and was fastened with a screw or bolt that looked very clean and tight. I pulled the wire on the lower bolt, connection and it felt snug.
I havent actually put a wrench on it, but I guess I could. But it sure seems nice and tight and clean.

------------------
88 GTA Charcoal Grey Bone Stock except for loose muffler which makes it a bit louder than normal.