theman4444

I'm pretty new to this so don't badger me too much. Okay, did a small amount of searching and found a little info on s4 but not much for s5. I am having a little trouble with my warm idle. It's actually just an annoyance than trouble. My engine used to run really smooth and idle was pretty much perfect, but now after some regular wear it seems to be rougher. I mean that instead of a constant 750rpm regular perfect idle to something like a slow fluctuation from 850 to 600. And it comes with this kind of sputter like it's okay then a small shudder that flows through the car and a kind of small pop. Not a backfire, just a slow spot where it stalls a small amout, then catches up. I'm trying to explain that it just doesn't run constant and as smooth. It doesn't affect the car in higher RPM's just the low idle. This is also the case still after i changed the oil and spark plugs.

Sooooo... I looked at the tps by just connecting the multimeter's positive to the green wire and the negative to the black wire and it was showing 1700ohms at 0% throttle and went to 3700ohms at WOT. I adjusted it to 1050ohms at 0% throttle but this was only after screwing the adjust screw ALL the way down. I was pretty sure that wasn't how it was supposed to work but i wanted to try it. Also messing with the adjust screw the WOT position at 3700ohms was not affected much at all. I tried my car at this level and it seemed to idle very high (around 1500 RPM).

Long story short I messed with the TPS in all ranges and it seemed to just make my car worse, so i just put it back to it's original place and went inside and hit my head on the wall a couple of times.

I have no idea now how to fix the problem and would like some help, please. I am ordering some bosch 8mm spark plug wires, that might give me some better spark to solve this rougher idle, but i doubt this is the problem. I guess my question is, do you think my TPS is bad since it can't get within the 1k - 5K ohm perfect range, or do you think it is something else. Spark, fuel, air? Thanks

theman4444

Can anyone just tell me if my tps is BAD?

theman4444

bump

Jaguarx7

Was your engine fully warmed when you tried the adjustment? If the fast idle cam is engaged at all it will throw off the reading. Even if it's close you shouldn't have a problem, because the s5 ECU has an auto adjust feature for the TPS. Sounds to me more like a grounding issue.

Jaguarx7

Also, be sure you're unplugging the TPS when you adust it, if it's plugged up the readings will be off.

theman4444

my engine wasn't as warm the first time i set it but then i got it warm and set it and that's when i started taking data on it. It was warm and i still couldn't get it set right. I read somewhere that if you have to make major adjustments on the tps to get it within spec, then it could be bad. But if that's the case I believe i would have a lot greater problems then just small sputtering at idle. Oh yeah and i did unplug it.

If it is a grounding problem where do i look for grounds and how do i fix them. Do i just add more grounds and a lot more wiring in my engine bay, do I take the current grounds off and clean them and put them back on, do i take off the old ones and replace them with new ones?!!!?!

Jaguarx7

First, to set the TPS, you can disengage the fast idle cam with your hand (it's on the back of the TB at the bottom, if you don't have cruise control you shouldn't have any problem reaching it), make sure the throttle is closed all the way, and adjust to 1k ohms (with TPS unplugges, of course). The ECU should adjust itself after that. As far as grounds, check all your grounds, make sure you're getting good contact. If the problem persists, upgrade the grounds using the method perscribed in another post, it's easy to find, just search for it. If all that fails we'll see what else we can come up with.