4nic8r

Hey Guys, I know your probably real tired of this topic, but searching the old posts didn't help.

I just finished a Rebuild on my buddy's 95 EX and the motor is great, like a virgin all over again, except for the idle. All of the onboard diagnostic systems have been reset and are functioning, all vacuum lines are tight, the idle and timing are set, all sensors seem to be in good shape, and there are no CELs being thrown. But still, after the car gets to operating temp, the idle begins to surge between 900 - 1300 Revs. It seems to be somewhat of an intermittent problem because after the fan kicks on for the third or fourth time the surging subsides to about the 900 - 1100 RPM range & AT TIMES it will go away for a while, only to return in a few more heat cycles. At first we thought maybe it was something to do with the purge Control Valve, but have since eliminated that possibility. The IACV has been removed, cleaned, and triple checked. I am completely stumped, we have no idea why this perfect motor wont idle correctly.

Also, are there any sensors on the IM that don't produce a CEL when they malfunction.

This is my first OBD II rebuild, so ANY HELP IS GREATLY APPRECIATED!!

nY's FiNeSt

try cleaning your TB plate or adjusting your TB screw

4nic8r

Done, didn't help.

thanks

pdiggitydogg

if its virgin motor check for vac. leaks

4nic8r

It's a TRUE Virgin, VERY Tight, no leaks.

Next.

youngkow

What you can do is unplug the IAC valve, and see if it goes away. If it does, then it's most likely the IAC valve, or you did something wrong in the wiring. Even tho it might seem like your IAC is working fine, it could still be not working correctly. Or like I said, the wiring could be off, since there is 2wire IAC valves and 3wire IAC valves.

EDIT : Did you bleed your coolant correctly?

boostin4drcivic

i just rebuilt my 93 ex motor after boosting at 9psi and frying my rings in 2 cylinders. put it back in and idle was screwed. bled coolant like 5-6 times and no dice. played with idle and no dice. finally last night i played with my fast idle thermo valve under the throttle body. that was my problem. but i had probs with surging after being started for like 30 seconds. if u have problems after it warms up, its something to do with ur IACV cuz that controls it after the FITV closes upon operating temp being reached. u may just have to get a new one. try one that actually functions right and see if that helps. may just be beyond a cleaning. the FITV and the IACV are the main two things, besides vacuum leaks, that will cause a surging idle without any CELs.

4nic8r

Ok, the IACV, when unplugged,throws a CEL & stabilizes the Idle to allow for adjustment. Then I adjust the idle, shut off the car, pull the 7.5 amp Back-up fuse, reconnect the IACV, and refire the engine. The engine warms and the idle surges.

This is just a REBUILD not a SWAP, so the 2 or 3 wire IACV is a non-issue.

pdiggitydogg

then how about air in your coolant

boostin4drcivic

i say top of your coolant and bleed it. after that try to swap out ur IACV for a known working IACV. that should let u know if yours is done. im pretty sure thats what ur problem is since i been working on this idle stuff for the last month or so.

Targa250R

Probably an air bubble in your cooling system somewhere.

4nic8r

Ok, I'll check the IAVC & bleed the coolant AGAIN. Anybody else have any ideas.

4nic8r

Checked a "known to work" IACV & bled cooling system again, and GUESS WHAT.

The Idle still surges.


Anybody?????????????????