KCA13

Anyone know what would make the car surge like this? I dont know what the problem is, I have not reset the PCM yet, but it was not a huge deal till i was backing out of a driveway the other day and car DIED! It started right back up, but it seems wheneven i give it some gas and let go it shoots down real low, like 400-300 RPMS. Then back to the idle of about 600. Ive also heard of a idle relearn you can do? How is this done? Thanks...

whatever

What kind of throttle body was it.

KCA13

Shaner S2

BillWS6Formula

Check the simple stuff first: all hoses/sensor's reconnected? Rest of intake track (bellow's/MAF/lid)? TB seated ok - all bolts retightened to 106in/lbs? Maybe even a damaged/dirty MAF wire.

35th LE SS

iTrader: (1)

If you also installed the converter at the same time it's probably the converter rather than the throttle body. I have a Yank SS3800 and every once in awhile my car will die at low rpms, backing up or coming up to a stop sign. Not sure why it happens, but my idle is low around 500-550prm. I think this is stock idle range, but with the higher stall, it seems to take more rpm to keep it running. Not sure why, I'm sure someone else could explain it better.

Sorry, this wasn't any help, but like I said I think it is more of a stall converter problem rather than the throttle body.

JPJBC

iTrader: (14)

adjust the idle screw on the throttle body...its prolly just not adjusted like your other tb was. should be an easy fix just adjust it and try it out until you get the idle back to normal. hope this helps

joey

RPM WS6

iTrader: (3)

My car did the same thing back when I just put the stall in. Stock un-touched TB at the time. I never figured out why that happened, I ended up raising the idle with Edit and that fixed the problem. Then I put a cam in and it surges slightly from time to time under certain conditions, but that's to be expected with a cammed A4...

jimmyblue

iTrader: (11)

I've heard that this is because the smaller,
lighter, higher-stall TCs have less of a
flywheel effect (especially down low where
it's all slip) and let the engine speed
move too fast, and the IAC control loop is
too slow to keep up (or anticipate). So the
RPMs can overshoot or crash (or do both and
give you an annoying idle surging).

I don't know if making it do the idle relearn
will teach it about this or not; have seen it
suggested, but won't know for sure until mine's
out of the box and on the car.

A richer idle mixture might help mellow this
out somewhat, a fat idle is less prone to lean
surging (because the engine is less responsive
to small air differences when it has more fuel
than it needs, than less). But this may also
make the engine feel less responsive in general
unless you can specifically target idle and just-
off-idle fuel cells. Only LS1-Edit could do this
"surgically" I think.