Rotaryrocket89

Hey guys, great site, I had a quick question though. I bought a 1989 GTU a few weeks back and lately it's been having a strange idling problem. It got to the worst its ever been today. I went to start it up and it idled fine and everything, then after about 15 minutes of driving I was in stop and go traffic and the idle was at like 10 and it stayed there, didnt bounce around or anything. I then turned the AC on and the idle went crazy, it bouced between like 2k and 600 and it kept bouncing around. When I turned the ac off, it returned to the low idle of 10 and stayed. What does this mean and how do I correct it?

JaredFreeman

sounds like the tps check the FAQ

Rotaryrocket89

I did but it only had tps adjustments for the turbo II. Also it says a common problem related is when the car dies when the ac is on. My idle increases when the ac is on and almost dies without it.

NJGreenBudd

iTrader: (1)

I think it would be the same procedure, they use same tps i think anyway, its easy, i just swapped mine from my '88GXL into my TII yesterday, sad to say it made no difference in my idle problem though...... Just check the resistance at the connector, the black prong to the black wire, red to the green wire, move throttle to wide open, should go from 1 to5, if over 6 replace, ,y old one went from 1.20 to +17.50, it was shot, but the new one in spec didn't help....

Rotaryrocket89

OK I found all this information on a checker lamp. I do not own one, is there any other piece of testing equipment I can use to see if my TPS is indeed the problem I'm having?

NJGreenBudd

iTrader: (1)

yes use your digital multimeter, ya know that electrical tester with the two leads that come off it, red and black, with the dial. Switch it to ohms and stick the black prong into the back of the connector for the black wire and the red prong into the back of the connector on the green wire in the TPS connection. This is the easiest method, resistance should measure betwee, 1.0 and 5.0 or 6.0 when sweeping thrpugh throttle position. Anything over 6.0 can cause problems, or opens, shorts or blowouts when the multimeter reads infinity. Hope this helps. you can buy a multimeter at autop store for $15, they're very good to have around.

Rotaryrocket89

OK, I've searched through the entirety of the Haynes Repair Manual for my 89 and can't find anything on the TPS. I searched through it because through all my searchings and readings I'm still not certain as to which is the TPS. Does anyone have a picture? Also, what is the relation to the TPS and the BAC valve and the Air Bypass Solenoid valve?

My5ABaby

iTrader: (7)

You need to get the FSM (downloadable, look in the FAQ section). It has things the Hayne's doesn't, such as where the TPS is.

FSM 4A (Fuel and Emissions - Non Turbo), page 4, shows where the TPS is. It's labeled Throttle Sensor in the diagram.

Go48

iTrader: (7)

You really need to download the free factory service manual from one of the links in the 2nd gen FAQ to get the correct answer to your questions. A description of the function of each of those devices is in section F1.

But here is a picture of a TPS. The TPS is the double-plunger thing in the middle of the highlighted area. The connector for the TPS is in the lower left of the highlighted area and the adjustment screw is in the upper right. You should make a two-LED test device (it's a simple task) to set the TPS properly.