hornbm

I'm trying to adjust the TPS on my S5 motor, and I went about it with a home made tester, that I found a write up on how to do.

The problem is, that I am supposed to turn the adjustment screw counterclockwise if none of the bulbs light up. Well no matter how far I turn the adjustment screw counter clockwise I cant get either of the two to light up.

The only way they light up is if I push down on the throttle. What am I doing wrong here?

Rattaan

Ok, try this. Forget the turning the screw direction. Start at the tightest point you can get the screw to turn in. Slowly turn out until you get a light. Start with that point and rerun the car to get it warmed again. Also, be sure you have the test connector grounded(it doesn't work if it's not, trust me I tried and tried )

You might also be able to move the entire TPS a little on it's mounts to help, just be sure they get tightened down when done.

TheHunt

If both lights light up, turn counter-clockwise

If both lights don't light up, turn clockwise.

pinkin

but what lights are you guys talking about? sorry for the ignorance.

eViLRotor

iTrader: (2)

You can test a tps in 3 ways.

A double light method using two bulbs. That's what they are talking about.

You can also use a meter, and adjust using voltage or resistance...

hornbm

yeah but what I'm saying is that NONE of the lights light up no matter what.

The only way they do is if you push the throttle down. Shouldnt they be on when you are not touching the throttle?

Aaron Cake

iTrader: (1)

Don't waste your time with the bulbs. Use a meter as shown in the Haynes manual and adjust for 1K resistance at idle.

hornbm

well thats the problem, I cant idle.

ViperKillerWannabe

If it won't idle it's not your TPS. It's most likely a vacuum leak or something else. The only thing the TPS does is turn off the injectors when you let off the gas to increase gas mileage and reduce the likelyhood of a massive backfire.

Nimisys

don't worry my lights wouldn;t stay on either... adjust it so you push slightly to get one to flash and if you pull out slightly the other will flash.

took me about an hour to get mine to set correctly when i replaced mine (since i was having loping idle issues)

ryans1000

I know from experience the resistance method can be unreliable, use the voltage method by testing the exact voltage going to the ecu.

Aaron Cake

iTrader: (1)

People's experiences can vary. In all the TPSs I've done (a lot!) I've never had an issue using resistance.

HAILERS

You need to read the book a bit more on the setting of the TPS.

One thing that is IMPORTANT, is to make sure the engine is fully HOT. The reason for this is a item called the thermowax. On a cold engine the thermowax moves the throttle linkage to a point the plates are a bit open. This act also moves the plunger on the TPS itself.

The TPS is supposed to be set with a HOT engine. They even mention it in the FSM and should have in any *writeup* posted on the internet.

So go out there and keep the thing running til the engine gets hot, and then immediatley go set the tps using the two LEDS.

The TPS is not what determines a idle on the car. You do need to set the TPS but then you NEED to set the timing with a timing light. Inductive timing lights are a dime a dozen. The rpms NEED to be below 1000 rpms when you set the timing, preferably closer to 750 plus or minus a hundred, but DEFINETLY below 1000 rpms is REQUIRED.

There's lots of reasons a car won't idle. The mention in a post above about a vacuum leak is important. Pull the Turbo inlet duct OFF. Look at the end where the duct connects to the turbo itself. Look for a CRACK in the mating area. Cracks are bad.

If that's good, then a poor vacuum line connection could be the culprit so spray with some STARTER FLUID around the vacuum lines when the engine is *idling*. Have someone keep the engine around 750 to 900 rpms while you spray. The rpms will rise when you find a leaking area.

Here's hoping nobody did the throttle body mod recently.

Also check you BAC. Turn the key to ON. Listen around the BAC itself to see if you can detect the BAC cycling back and forth at about 120 times a minute. Usually you can hear this sound at the airfilter area.

The BAC plays a PART in the idle of the engine. But NOT the only thing that causes a good idle. With a properly set idle you should be able, with a HOT engine, to pull the BAC's plug off and the engine still idle. It may drop a hundred rpms for a moment but the engine should still idle. Again, the BAC isn't the only thing that causes a good idle.

Did I mention the engine needs to be HOT when setting the TPS???? If I forgot, then *the engine needs to be HOT when setting the TPS*. There's ways around that but I'm outtta time.

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