Hi peeps,

Over the last two weeks my Zed's idle has been way to high. It's a auto and while in drive it idles at 1100rpm, and when in park 1500rpm.

It is a prick to start as the idle hunts from 500-1500rpm before settling at 1000rpm. I have swapped the IAA over (as I had a spare) with no change at all. My question is, could a bad electrical connection to the IACV cause these symptoms? The unit itself was given a overhaul and clean when i had the plenum off a few months back.

Any help would best most appreciated, as I have a long road trip this Friday :shock:

Try cleaning the yellow connector terminals on the temp sender, also terminals on the maf too!

hope this works for ya :)

might be of some use :) http://www.300zx.co.uk/forums/showthread.php?t=74884&highlight=idle

i have the same kind of problem. was told that cleaning my throttle bodies would help cure it. will be doing it next weekend so i'll let you know how i get on.

Thanks guy...

TB's were cleaned when the plenum was off recently also. I have checked ECU for faults, and came up with code 55 (no faults). TPS is set to .44, AFM connector was cleaned (haven't touched sensor, but visually it looked clean).

As I said before, I have installed another air regulator... and still no change. Last night the Z was a nightmare to start, engine would turnover and fire with revs around 1500rpm and then drop immediately to sub 500 and stall. After 4 attempts I finally got her started.

I'm lost.

I'm hoping it's either the connection to the AAC valve, or the FICD solenoid. If one of these connections was broken, could they cause my current symptoms?

Thanks again :)

99% sure I have found the problem :)

I did a boost leak test 3 weeks ago, before I was on the dyno... but really should have done another since this issue occurred.

 

Well it was a serious boost leak, and not the sort you'd expect. Could hear plenty of air pissing out from under the LHS SMIC (after market). After removing the front bumper in record time, I found it was the SMIC itself leaking from the hole on the back that you screw the support bracket into

 

A bolt and some plumbers tape has fixed the issue. Yet to take it for a drive, but idle seems to be a lot more stable.

I spoke too soon, the saga continues! :(

 

It seems when the TPS is in closed circuit the timing was showing 35 degrees. When I applied some throttle & turned off the closed TPS circut the timing was showing 15 :confused:

What does this mean? Air/fuel ratio is showing lean on these, but it was actually flashing between lean/rich.

 

Sorry guys,

I was jumping the gun... I'm still waking up! Timing is reading fine (15) on data scan once operating temps were reached.

Hi

 

Do check the throttle linkage is free and returns fully.

 

I know this sounds daft, but for a while idle and revs rose, and then one day throttle started partially jamming open and it took some stopping by the side of the road. Found a little plastic cover had worked loose and jammed under!

 

I know others have had similiar problems with a pipe on the front of the plenum coming loose and obstructing linkage- extensive posting on here.

 

Just a thought!

 

Regards

 

Dave