SnowmanFD
Proven Member
- 142
- 8
- Dec 11, 2021
-
North Seattle,
Washington
90 talon tsi, my idle jumps around and even got stuck at 2k once even after it was warmed up. Any idea? I dont even know where to start.
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Idk you tell me?Throttle cable have sufficient slack in it to not hold the throttle open???
You have no cooling fans.Thanks a million this helps a ton.
I plan on testing it later today, if it is broken. what are my options for fixing it? i cant seem to find one for sale also Ive seen people just delete the whole isc would that be a good idea? What are the pros and cons?
Also here are some photos of the whole engine bay. Let me know if anything else looks wrong
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A simple wire will do. Factory just made it pretty.So i just tested the isc and got good readings so im thinking its just because its not grounded is there somewhere i can buy the part from or do i need to have one custom made?
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It looks like your brake and clutch reservoirs are empty.Thanks a million this helps a ton.
I plan on testing it later today, if it is broken. what are my options for fixing it? i cant seem to find one for sale also Ive seen people just delete the whole isc would that be a good idea? What are the pros and cons?
Also here are some photos of the whole engine bay. Let me know if anything else looks wrong
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As Pauleyman stated, the ground is key for proper IPS function. Fixing my IPS cured my erratic idle.You must replace the ground on the throttle body. The throttle body does not receive a good ground because it's gasketed. The solution was the factory ran a ground direct from the top to one of the bolts that holds the throttle body to the intake. The intake manifold is itself grounded to the body. Without this ground the ECU does not know if the idle position switch is working because it can't go to ground as it doesn't have one. That is part of the idle control process and you're missing that step.
then make sure your IPS is properly adjusted to your throttle stop plate. This requires a 14mm wrench to break the jamnut on the bottom of the IPS, and then screwing in the sensor until it bottoms out on the throttle stop plate, making sure you are not actually moving your throttle body shaft with the sensor. You should then recheck your TPS voltage and make sure you are still at 0.63v fully closed.
You can check that the ISP is making contact internally by using an ohm meter on the top of the ISC spade terminal with the wire unhooked, and the other lead of the ohm meter to your ground strap or any clean connection on the throttle body. With the ISP closed, you should see continuity (will beep if you have a sound setting). If you open the throttle plate, you should see 0 continuity. I would repeat this process a couple times and make sure you have continuity every time you open and close your throttle plate. If you don't, your ISP is not making good connection internally, you do not have the ISP tight enough to the throttle stopper plate, or an out of adjustment throttle cable isn't closing your throttle fully every time.
Also, if your coolant sensor isn't hooked up, you will need to fix that so your ecu can use the temperature (180-190 IIRC) to go into closed loop (used at idle)
I see that a little differently. Definitely don't just wade in and change it to see what happens. But if an ohmmeter measurement or scan software says that the idle position switch isn't closed or reliably closed when the throttle is closed that car will never idle right until the problem is fixed. It can't because this switch tells the ECU to take control of idle speed and as explained, 'idle speed' is a complicated job -- engine warmup, air temp, accessory loads, dashpot (slows the rate at which RPM falls when you come to a stop so the engine doesn't stall) -- all are taken into account and symptoms can be just about anything that can happen when the throttle is closed.Touching the IPS adjustment should be a last resort. The adjustment is critical to the throttle body operating correctly and the FSM strongly recommends you not touch it.
I haven't had very good luck with the FSM procedure using a feeler gauge, I think because there's wear causing the switch to behave a bit irregularly. What has worked better is trial and error until it closed reliably under all situations and opened immediately when the throttle did.