Okay I've pretty much replaced all my vacuum hoses on this 89 TII I have! It runs alot better but it still surges at idle! I've double checked to make sure there are no other hoses blowing off while I'm driving it and it's pretty much sealed up (vacuum hose wise) but my only problem left is my surging idle! I've checked my TPS (car at operating temperature)with my voltage meter and it was showing 1.56 volts so I readjusted it down to 1.000xx as close as possible, took it for a spin, guess what it runs alot better but still there is a surge! I popped off the intercooler and checked the voltage again with my fluke multimeter it now shows voltage wise! 0.998 volts I was like what gives, I readjusted it again and then got it to 1.003volts, this time I had a friend stepping on the gas pedal for while I check what the voltage reads and each time he steps on it I'm getting inconsistent readings that vary from 0.98xxx all the way up to 1.10xxx! Is there an adjustment to the throttle cable, cause I can literally touch the arms that the TPS sensors get there range from and watch the voltage change change I guess it needs some tightening or maybe this throttle body needs to be rebuilt! I don't know I am really getting frustrated with this car maybe this Tbody needs a rebuild but who in the world does rebuilds for this unit! If anybody can throw there 2 cents in that would be great!
Thanks, Jon

 

Normal. Loosen the throttle cable some. Adjust the throttle set stop screw. And make sure the car is fully warmed up, otherwise the fast idle cam is going to be engaged.

Good luck!!

 

Dittos of the above. That small difference will make NO difference at all. I trust that was the low range.

The surging at idle MIGHT be a vacuum hose going somewhere it should not go. An example of this would be on a non-turbo car. At the front of that throttle body are three vac hose. One large will go to but one place. The other two are the same size. IF you swap those two hose....you get surging. Why? Because one nipple on that throttle body is vacuum and the other is NOT vacuum.

YOur problem may be something totally different. That was but one possibility. An I have no idea at all where series five vac hoses go. I've proven that numerous times and have finally stopped trying to figure out where they go.

Try this. After the car is fully warm, and is surging, take the bac plug off and see if there is a difference. If there is a big difference...that may be a clue.

 

Hailers, you could be right about the vacuum hoses being in the wrong spot I tend to question that when I was replacing all the hoses but I don't have a factory diagram to tell me exactly were each hose should be going. All I did was replace everything that kept falling off it's vacuum nipple or what ever vacuum hose easily came of with no tension I replaced and zip tied it! My car is an S5 model and yes that was the low range I was doing the voltage test on! Maybe being sold I might have to put a little tension back into the TB cable because it does look liike it has a lot of slack in I just don't know what to adjust too many cables to work on I have to go and look at my little downloaded book of the 89 manual! Maybe that might help! Is there any place on line that can tell me exactly which were each vacuum hose should exactly be plugged into!
Thanks again for responding!

 

1.0 +/- 0.1 is well within range.
It only has to be close.
Your TPS is probably OK.