non camaro idle problem

maybe some of you techies can help me out.. Cant find none in the c/k forum

my winter truck, a 1996 GMC 1500 w/ a 305 vortec SMPI auto trans..

Took the intake and MAF off to clean the throttlebody, started the truck and sprayed the TB til it was clean, sprayed the MAF with tb cleaner, and re-assembled..

Now it wont idle under 1000rpm.. when I start it, or when I put it into park, it will race up to 1500, than back down to 1000.. It still idles as smooth as it did before, and drives the same (other than the tranny shifting harder because of the high idle)

Could this be a fried MAF? ive never had a bad maf before.. Anyone know how to test it? Also, when I unhook the TPS, Nothing changes, it runs exactly the same w or w/o the TPS hooked up.. could this be a bad tps?

Yes it could be MAF related and you cleaned it?

How?

the maf wires were very dirty so I sprayed it with throttlebody cleaner..

the engine light is on.. has been for awhile, Anywhere around here charges an arm and a leg to scan the codes..
I ordered a obd2 code reader off of e-bay.. Might just havto wait til I get it..

I have heard and strongly agree not to touch those wires. They are extremely sensitive and I would never put chemicals on them. I would bet money you have a MAF code stored.

yeah I know your not supposed to touch them.. But people clean them with chemicals all the time.. Ether is a common choice, but Ive cleaned many MAF's with throttlebody cleaner.. But im startin to think I fried it too.. Ive checked EVERYTHING else
Do you know any ways to test the MAF??

I read this method in my service manual but never tried it. It says if you tap on the flat part of the MAF while the engine engine is running. If it stumbles or stalls it is faulty.

hmm.. i'll give it a whirl, thanks

aside from the MAF, I pulled the TPS off today, and on the inside of the tps (where it slides on to the throttlebody lever) it was very loose, I could move it in and out quite a bit, and there was no resistance when i turned the tps, I could turn it all the way in one direction and it woulnt spring back.. arent they all spring loaded??

Did it turn freely in clockwise and ounter clockwise directions?

well when I took it off it was fully counter clock-wise.. but I could turn it freely clockwise then back.. in total it would turn about 60 degree's

so yes, it turned freely clockwise and counterclockwise..

Thats weird. They are not suppose to be able to move like that. May be something to look into but that would show up on the scan. Not worth guessing on til you scan it.

I figured it might also be the problem because there was absolutly no change in idle or driving with or without it hooked up..

I could unhook it while the truck was running and there would be no change

I unscrewed it from the throttlebody but left it hooked up, and started the truck.. even if I shook it a little bit or tapped on it the idle would go crazy..

Ive adjusted and replaced TPS's on a few vehicles before and have never seen it do that.. But Ive never had much experience on 95-newer vehicles..

especially this Vortec..

Those are non adjustable on those cars so it doesn't have adjustment screw but it isn't suppose to be lose either. It just may end up being your problem but I don't recommend cleaning your MAF either, to anyone

In an attempt to gain a little bit more knowledge, why can't you clean it? I understand that they are sensitive, but what makes them that touchy? Also, what are the signs of the MAF being bad. Is it going to be an obvious problem, or is it just going to rob power without you knowing it?

MAF sensor wires are protected with a screen so as not to get touched and how it works is the thin wires are heated by voltage and the air that enters and passes the wires cool the wires lowing the voltage. The PCM measure the voltage remaing to see how much air is passing the wires and adjusts the injectors and IAC settings accoring to this. So imagine putting a flamable solvent on wires that get heated and second imagine rubbing super thin(line the size of a lite filament) with a rag. Not only can you make the wires thinner or run hotter throwing off the PCM. You can weaken them causing it to burn up or break later on.

to add to your explanation.. The PCM senses the voltage it takes to keep those wires at a certain tempature.. BUT when you have dirt and pollen build up on the wires, it takes more voltage to heat the wires, then the PCM senses this, thinks there is more air coming in than really is and adds more fuel to account...

The thing with using throttlebody cleaner or Ether is that it dissolves very quickly and dissolves moisture with it.. Making it ideal to clean the MAF.. Ive cleaned a dozen of them (most recently a 97' Camaro RS) But you are never supposed to touch the wires with your hands or rags..
Im wondering if maybe mine wasnt completly dry when I hooked it back up and started the truck..

Also, I know the MAF is working to some extent because I tried running the truck without it and it wont run at all.. Also, the truck idles and drives quite smoothly.. Just idling very high..

Im gonna pull the TPS off the other truck n' give that a whirl

mine was completely covered in black crap, and I couldnt get all of it off with electrical cleaner. I ended up using a tissue. Should I worry? Whats a sign I should watch for that its bad.

stalling or heavy smoke or running rough. You can also try the test I mentioned to Damone.

DaMoNe6969. A '96 should have OBDII.Autozone will pull codes for free. Also Autozone's website has most auto manuals available online which can tell you how to test sensors or most sensors.

DaMoNe6969. A '96 should have OBDII.Autozone will pull codes for free. Also Autozone's website has most auto manuals available online which can tell you how to test sensors or most sensors.

thanks for the tip.. i'll check the website out..
But we dont have autozone in canada and the canadian equivalent charges an arm and a leg to scan OBD2.. $70 bucks for 1 minute of work