Need help with high idle
09-07-2010, 05:12 PM
#1
Need help with high idle Long story short, I installed a Shaner S3 throttle body and it idles very high, 1300-1500 rpm.
For the first drive its perfect, spot on (when cold). After that it starts learning itself higher and higher and eventually throws the high idle code. It also surges at idle, by about 50rpm (when warm). The TB is fully closed, set screw is all the way down, and the IAC counts are between 40-60 and bounce around a lot.
All the info I can find are for people having a hard time getting the car to idle because of cam installs, etc. Can anyone point me in the right direction to get the idle down and steady? I tried referencing a tune that had the same mods as I do and it did nothing at all when I made similar changes, so I'm assuming I'm missing something.
For the first drive its perfect, spot on (when cold). After that it starts learning itself higher and higher and eventually throws the high idle code. It also surges at idle, by about 50rpm (when warm). The TB is fully closed, set screw is all the way down, and the IAC counts are between 40-60 and bounce around a lot.
All the info I can find are for people having a hard time getting the car to idle because of cam installs, etc. Can anyone point me in the right direction to get the idle down and steady? I tried referencing a tune that had the same mods as I do and it did nothing at all when I made similar changes, so I'm assuming I'm missing something.
09-07-2010, 07:34 PM
#3
I have already checked for leaks and replaced the TB gasket just in case. Its definitely a tuning issue. I swapped back in the stock TB because its pretty quick and it works fine. I ended up swapping the blade out for my stock one since the previous owner has drilled the hole bigger, I thought that might help but its still the same.
The TPS and IAC valve are also the same from my stock TB and they work fine.
The TPS and IAC valve are also the same from my stock TB and they work fine.
09-07-2010, 08:04 PM
#7
I read most of the stuff in there. Its very helpful. I have tried relearning the idle a few times, and it works GREAT for the first 10 minutes, but as soon as I drive it, back to the old 1500rpm idle again.
I'll log the TPS voltage and see what it is. I just start the car, and again when its cold and the IAC hasn't come into range, it idles smoothly at exactly 800rpm where its set.
I'll log the TPS voltage and see what it is. I just start the car, and again when its cold and the IAC hasn't come into range, it idles smoothly at exactly 800rpm where its set.
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09-07-2010, 08:57 PM
#8
TPS is a constant .57v when the car is at idle.
I logged cold start, idle is 790-810 rpm IAC at 0. It stayed that way even when the ECT got up to 198*. I backed out of my garage, idle 750-1150rpm, IAC 0-40 in about 1/2 second increments.
I logged cold start, idle is 790-810 rpm IAC at 0. It stayed that way even when the ECT got up to 198*. I backed out of my garage, idle 750-1150rpm, IAC 0-40 in about 1/2 second increments.
09-07-2010, 11:16 PM
#11
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With the IAC valve removed compare the internal seat that the pintle contacts, as well as the size of the passage in the seat. Wouldn,t surprise me if this has been modified or damaged to cause this issue. Also check the depth of the seat from the iac mounting face.
09-08-2010, 05:22 PM
#14
Okay I checked the IAC seat and surrounding area, it looks like the same as my stock TB. It seems to have whittled its way down to 1000rpm now, but it still bounces up and down by 50rpm every 1/2 seconds or so, and the idle takes ~15-20 seconds to come down after I put the clutch in and stop moving.