idle problems

[Shae]

Hello, for those who dont know me (most of you) my name is Shae

My 1992 SSEi is sick :(

I am having weird idle problems, when i start the car, it will jump to 1500 rpm, then a few seconds up to 2200 ish.. then after a few minutes, it will drop to normal idle, HOWEVER, everytime i push the gas, even a little bit, it repeats this, up to 1500 then up to 2200.. Oh, and this is intermittend, 9/10 times it does this, and the occasional one time, once the car is hot, it runs fine..

I have been reading all through this forum, and have tried many things.

-Replace IAC motor
-Replace 02 sensor
-Clean MAF
-Replace Catalytic Converter
-New Spark Plugs
-New Wires
-New Air filter
-Tested TPS sensor
-Checked all vacuum lines for leaks (with carb cleaner)
-Replaced leaking valve cover gasket (front)

TO DO:

-Remove and clean TB
-Replace IAT sensor
-RE-check for vacuum leaks (incase I missed something)


Please anyone who knows a thing or two, or had similar problems, any sugestions or insight would be greatly appreciated!

[J Wikoff]

Try a couple things.

Unplug the MAF sensor and see how it runs.
Unhook the brake booster vacuum line, plug it to prevent a huge leak, and see how it idles. (Don't drive with it undone).

[Shae]

I will try the brake booster,

I have tried unpluging the MAF sensor, the engine immediately stalled.

Another thing I forgot to mention:

I waited for a normal idle while the engine was hot, unplugged the IAC valve, and gave it some gas, it IMMEDIATELY returned to normal idle. I did this same test with the old one, which is why i replaced it, and now it does it with the new one too.. As soon as I plug the IAC back in, the problem comes back. Again, with the NEW and OLD IAC valve.

[J Wikoff]

Does your throttle plate close all the way at idle?

Any chance of getting a live data scanner on it?

[Shae]

Alrighty, tried a few things, as sugested, now im thinking it may be a imporperly adjusted TPS sensor, when I unplug the sensor, my idle problems stop, it idles normally, and as soon as i plug it back in, they come back, although I do seem to get the correct voltages while testing the TPS sensor with a multimeter.

I am going to take apart the TB for cleaning, and when its apart I will check the plate, as well as replace and adjust the new TPS sensor. With any luck that will fix the problem.

Also I noticed the clip is broken off my TPS sensor harness, However it was firmly in place, I guess this is a common problem, the clip gets old and brittle and the snaps. So with any luck I will also be able to find a new harness, and solder it in.

[J Wikoff]

The 92 TPS is adjustable. Try that before you buy a new one. Remember, a little goes a long way when adjusting it.

[willwren]

When you remove the TB, do not disassemble it. Clean it thoroughly, paying particular attention to the IAC passage and the area around the throttle plate that may cause binding and prevent it from closing completely. If the throttle plate is partly open, the IAC will not be able to compensate, even if it closes completely.

Lubricate the pivot points and springs on the TB with some light oil (NOT WD-40, it's not a lubricant, WD is a water-displacing solvent, and does have some use in cleaning jammed parts). If you remove the throttle plate from the TB, it's difficult to get it back in where it moves freely without jamming.

Use the Techinfo article for pulling codes first though. Ignore code 12 and code 58, and tell us what else you have. Code 12 is the handshake to verify comms, code 58 is a known bug in the 92 PCM.

[1oldman]

While you are at it, check the plug on the wiring harness to the TPS. I have a '92 and I think it is a poor design. The later models have a different (and I think better) design TPS plug. - BC

[Shae]

I have not yet cleaned the throttle body, but for whatever reason, its been working perfectly the last few days, then today, back to the same problem when i drove to work, then on lunch break, no problems again.

So it's intermittent, Is it possible that there is moisture building in the harness for the tps sensor, and the water is causing a connection between the +5 volt and the output wire, just enough so that it throws off the idle?

I ask, because I poped out the harness today after the problem came back, and it was a little damp, i dried it off, and now its working good again.. Weird.

[renchjeep]

This is what I would do:
Clean both ends of the TPS connection with contact cleaner, make sure the metal contacts are not bent or "wallowed out", apply a bit of dielectric grease to the connectors, re-connect and see what happens then.

[1oldman]

I have not yet cleaned the throttle body, but for whatever reason, its been working perfectly the last few days, then today, back to the same problem when i drove to work, then on lunch break, no problems again.

So it's intermittent, Is it possible that there is moisture building in the harness for the tps sensor, and the water is causing a connection between the +5 volt and the output wire, just enough so that it throws off the idle?

I ask, because I poped out the harness today after the problem came back, and it was a little damp, i dried it off, and now its working good again.. Weird.

I was successful in locating a TPS plug (new) on ebay(?). I also purchased a TPS (Delphi - new) for under $18 at the same time. If you need the seller(s - ?), I will gladly give you the information. - BC

[renchjeep]

BC--I could use that info, for the next time my TPS goes haywire. Nice to have a spare....

Chris

[1oldman]

BC--I could use that info, for the next time my TPS goes haywire. Nice to have a spare....

Chris

These are current listings. Off hand, these are close to what I paid if my memory (ha ha!) serves me correct. sorry it took so long to answer - BC

NEW BUICK THROTTLE POSITION SENSOR SS10431 (Delphi) $20.00
http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0582699563

Throttle Position Sensor Repair Pigtail Connector GM Cars and Trucks $9.99
http://www.repairconnector.com/products ... rucks.html

[Shae]

Awesome, I will be ordering those my self as well.