He's temporarily removing his intercooler and replacing it with a bypass pipe made from pvc so he can access his tps and throttle adjustments easier. Once he has diagnosed and fixed his problem, the i/c goes back on. Kapish?

 

okay thanks for the answer buddy

 

Thats a weird idle man thats exactly what my car sounds like when i turn the key in the morning and dont give it gas. Once i give it gas though it idles properly.

 

my car has the same issue (89 vert n/a auto) and if I unplug the tps it will veen right out and idle great...

I am waiting to get a new tps but to be honest I dont know what screw everyone is talking about to adjust the tps..

 

there is a screw that adjust how far the sensor sticks out when at rest, it's got a little spring around it...

and i agree it is a weird idle, it sucks......but we'll get crackin on this stuff this stuff soon, i'm gonna do the pvc tomarrow moring before work hopefully...

 

The FSM has a clear picture and description of where the adjustment screw is for the tps and how to properly adjust it. The tps adjustment is critical, and most often if there is a "dead spot" or a "glitch" in the tps signal, it will be at or very near the idle position, the tps spends most of it's time between closed position (idle) and about 1/4 throttle during most daily driving, so it makes the most sense to find glitches in this range due to wear. The tps is one of the main sensors used to determine when to shut off fuel during decel, along with the rpm signal. If it isn't adjusted properly, the control unit can't get a precise "read" which can lead to intermittent problems.

 

did you unplug the TPS yet??? that only takes a minute.

 

after watching the video and NOT reading every single post. I vote, vac leak

TR

 

if I unplug my tps the problem goes away unfortunatly I cant start the car without the tps on.. but I can drive it once started

Dave

 

I just installed the pvc this morming, but I have to go to work thi svery minute, I'm actually cutting it too close for comfort but the TII deserves some of my precious time as well, so here it is, feel free to make fun. I'm no plumber and I accidently glued the wrong piece together so I had to make use of a connector I found in my basement, it's not as pretty as it was ssupposed to be but it will give me room, I'll probaly do the tps check tonight.

Before :

After:

 

That's a fine looking job to me. We're not looking for aesthetics here, just access to the tps, p/s solenoid, thermowax, dashpot, etc. Keep us posted.

 

I'm going out right now to see what I can find out for you, I'll post back when I come inside afterwords. Thanks for your support.

 

Okay.

I started it up and allowed it to warm up, I noted a couple things:
when it starts the idle is idefinately stable at 1900rpms, though the tps was still reading 16, so then i tried to manually move the tps, when i depressed the plunger it read 5.

When I unplugged the TPS, the surging stopped stopped and the rpms rose smoothly over a couple seconds to 2200 and stayed there until i plugged the TPS back in.

I have more but wanted to post this right now for input.

 

so it was confirmed by the log on the palm, when the tps was unplugged it read 100% and the rpms climbed to 2200 but it was smooth, so what i guess the tps is shot after all or no??

I don't know, this was the tps from my GXL, which ran perfect before it sat, so i figured this one would be okay, it checked out with the impedance meter but I don't know what to think....

 

also when i removed the intercooler, i was left with an open tube on the air bypass valve and an unplugged hose from the back of the throttle body somewhere, both of which used to connect to the intercooler. Should I just plug these or leave the, open when running the car with the IC removed? I pluged them with my fingers but it didn't seem to make any difference in how it ran?

 

thats good news. its partially the tps then. now you have to find why the idle stays high. if you dont know where the hose goes to, plug it. or you can post a pic of it. generally you should plug it no matter what people say haha.

try checking out the warmup system. all of it . i would still shoot some compressed air in the intake and see if u have some vac leaks first. u can find a write up of doing that on here.

bac valve still unplugged? 2200 is pretty high, still sounds vacuumish.

 

You don't have to plug either of those two hose, especially since putting your hand over them did not result in any change in the idle.

The hose in the rear would suck air if you had power steering and turned the steering wheel.

The TPS defaults the ECU to a 100 percent TPS reading, when it's not working/plugs off. That is stated in the manual.

I still think the throttle plates are being held open a touch. It does not take much of a gap to raise the rpms.

 

And the next time you have the TPS connected up, look at the Palm while you depress the pedal slowly and then release the pedal. The numbers should go up/down without anything peculiar.

Again, the TPS should read 20 percent on the PALM if set right and the engine is hot. One volt out of the five vdc ref equals....twenty percent. In other words if you looked at the output voltage of the tps when set right, it should read one volt dc approx. IF the engine is cold, it'll read much higher and that is natural because the waterthermowax plunger has moved the throttle shaft as its plugnger retreated into its housing as it got colder.

 

Actually, now that I think about it, you might plug the hole in the line feeding the AirBypass Solenoid. It SHOULD be opening on a cold start for 17 seconds, then close off.

 

Hailers is right, just make sure you are aware that the air bypass solenoid and the p/s assist solenoid are 2 different parts, the p/s assist valve being at the rear of the upper intake close to the firewall. I was thinking, with the tps showing 100% while unplugged, that alone could be giving you the 2200 rpm idle, with a known-good tps properly adjusted you might be all set. Oh and what year GXL did the tps come from?...my S5 GXL has 2 tps sensors....a wide-range and a narrow-range. Are you using the correct tps?

 

actually I forgot to leave the BAC unplugged, it was plugged back in when I did all of this last night.

I'm gonna try it again with the BAC unplugged, and see if the reading increases slowly if i press the gas pedal.

So I'll let the engine warm p and set the tps so that it reads 20 when hot. This TPS is from my '88 GXL, my TII is an '87 so I figured they were interchangeable. I know the S5's had the dual sensor and these are both single.

Again: the Air Bypass Solenoid Valve is what people are calling the AWS according to my FSM, it's located on top of the intake manifold, and then "p/s assist" is the Air Supply Valve on the back of the manifold...right?

let me go see if i can screw that screw in and release the cam from the the pin and see if it's any different w/ BAC unplugged and thermowax reset. Thanks.

 

(((((Again: the Air Bypass Solenoid Valve is what people are calling the AWS according to my FSM, it's located on top of the intake manifold, and then "p/s assist" is the Air Supply Valve on the back of the manifold...right?((((((((((((((

Yes. Acutally just unplugging it's connector instead of plugging the line would do the job.

Correction: I unplugged the tps on two cars this morning and they defaulted to 74 percent as read on the RTEK2.0. So maybe I need to re-read what I thought I read in the FSM.

 

yay!! some encouraging results:

So I unplgged the BAC, let the engine warm up and then unplugged the TPS, and the same thing happened, surging stoped and the rpms climbed to 2200.

But here is the god stuff, I tried to adjust that screww by turning clockwise, this screw, I don't know if it was the right ne or not, and also I think the gap in the throttle stop is bad, look at the pic and tell me if it was the right screw and it that gap is indeed bad. Si i turned this screw clockwise a bunch of timesl almost as far as it would go and the idle did stabilize at 1475...



But when I turned the screw back counterclockwise the surging started again....

....also the TPS does move rather smoothly when applying gas via the pedal,shown by the rtek, as I said it checked out with the resistance check before and was known to be fine a year ago...

 

I just want to thank everyone for the ongoing help and support, if it weren't for you guys, I would have given up by now. You guys are like annonymous heroes....

Here's a short video of the crew being messed with, it was already turned all the way to the right when the vid starts :

 

I gotta say I wish I saw more threads like this on the club. Question with content rich posts, professional help with no arguments. It's a diamond in the rough