IAC and high idle after swap

[vrg3]

You're not supposed to reuse throttle body gaskets, so, yeah, maybe there's a leak there.

Check out these cool links!

http://bbs.legacycentral.org/viewtopic. ... 427#102427

http://bbs.legacycentral.org/viewtopic. ... 097#112097

http://bbs.legacycentral.org/viewtopic. ... 4812#44812

[Natoe]

thanks! ill try those things

[Natoe]

well a coolant line broke, and i fixed it stranded on the road by just bypassing the TB but still have coolant to the IAC. now though... the CEL is always on and its acting like its in limp mode... (6psi tops feels like its pulling timing) off boost its perfectly fine, but the CEL is on and boost makes it feel weird and very slow.

now i did run it for 4 minutes without coolant before i realized and turned it off ASAP... CEL was on for that. i will do the proper ECU reset to see if it just needs cleared, then get the code if its still there, i just wanted to make sure that what i was experiancing was it just being in limp mode...

why cant everything just work!

[Natoe]

pulled the codes before i reset the ECU...

22-knock sensor
!!! what can this cause? limp mode? pull too much timing? thats what it felt like.

24-IAC
expected/fixed enough for now
31-TPS
expected/fixed
49-MAF
expected/fixed

[Natoe]

LOL! so i looked at the knock sensor, and the ECU side plug (small male side i believe its called) the wire was so old and brittle it snapped off but was still kind of giving a signal sometimes (the reason for it coming sometimes at idle, and always now)

ill fix that, should really help..

[Natoe]

66bucks for a new knock sensor and she runs beautifully.. except for the idle.

[Natoe]

k, sounds like im talking to myself but i figured someone might want to know that i fixed my idle, turns out the closed and open wires were switched idles right at 700-750 right now very smooth.
one last thank you for all the help!

[vrg3]

Great!

[LondonThing]

66bucks for a new knock sensor and she runs beautifully.. except for the idle.

This is more or less where i got to this weekend. Every so often the idle would jump to 2000 (smooth-running) then falter back off down to 1500-1800 and the car woudl then jump and stagger.

Took it to my fixer and he read off the MAF sensor and Knock sensor as fault codes, so we swapped those out and I drove back - to find things had got worse, not better!

So I tried two fixes at once (dumb, I know) and BOTH took the battery neg off AND attacked the ICV. Mine had white paint marks on the actuator (and I couldn't take the whole valve off without taking the intercooler out...) so I whipped the actuator off. It's a weird thing; not really an electric motor or a geared servo, but a big highly magnetic thing. Mine had a few bits of swarf around the top of the valve post, and swarf always equals grief; so I cleaned all that out, put everything back together and gave the post a good waggle. It might have been stuck at one end of it's travel - it's kinda hard to tell.

Put everything back together and re-connect the battery, and hey presto - smooth idle restored. Lots of other things are smoother too - the infamous "thumpy" change from 1 to 2 has vanished, though that may be because the ECU is hanging back on full boost - I have yet to really thrash it.

[Natoe]

hmm the knock sensor made it run really slow and in limp mode, but my IAC problem was different than yours. i just had the wires switched, when i fixed that it idled perfect and i can start the car without any throttle as well.