rich idle

[blackdeath]

so car is tuned runs awesome , but 2 days ago , car started to idle rich .. o2 plugged in 02 unplugged , something is pulling it rich . its booked back with tuner , but curious to know if any of u ran into this , iac good ,temp sensor good , maf brand new and clean unless its faulty. no vac leak or exhasut leak althought unplugging o2 would remove exhaust leak out of the mix .

any other idea ?

oh even leaning it out with laptop , the mixture will still pull rich after .. idling aT 11.8 LOL

what are the specs for maf at idle ?

[kai]

Checked the ecu for codes yet? could still be a sensor related problem...possibly faulty tps, although that usually causes a surge and stalling..

[blackdeath]

no codes my friend

[kai]

Does the AC when on, cause any black smoke to spew? Also depending on how many mods have you ever had it tuned? basic question yea but somethimes thing's really don't line up...especially under the stock ecu

[kai]

Also could be the BOV if its aftermarket and is venting to atmosphere and not plumb back..if its atmo then put your hand over the BOV outlet and see if you have any change in idle..i would also clean the AAC and AFM! good place to start anyhow man.

[blackdeath]

nistune and its tuned , i did mention that on top , iac is new and no the bov does not take in air , those were my first checks , like i said was tuned 2 weeks ago , and its just started to do this 2 days ago ,,

and ac is deleted

[kai]

All you sure you don't have even miniscule cracks in the hoses? And does it only run rich once it's warm? or both warm and cold? If you tested for Vac leaks when the car was cold, the hoses may not have had a chance to expand..also if you just listened for them, it may have been difficult to hear over the motor if they're just small, but numerous small crack could cause the engine to suck in more air and in turn run rich...11.8 sounds pretty retarded though LOL..

[blackdeath]

yea sure does lol , its going to the tuner tomorrow , as for vacuum leaks its been checked cold and hot , with spraying carb clean and water

[kai]

Bigger/highflowed injectors (that or they're clogged to **** and need cleaning. again bigger injectors is something that needs to be tuned for).
busted oxygen sensor.
Aftermarket adjustable fuel pressure regulator set to the completely wrong pressure?
Base timing is wrong (timing belt skipped a tooth or teeth)....
Broken/malfunctioning coolant temp sensor (car will be stuck in cold start enrichment and drink fuel)
Massive boost leak, metered air is escaping out the cooler piping before it gets to the engine (joiner blown off, common on the ones near/on the intercooler). Though it would hunt badly while idling.. Last things that really come to mind, if it's going to the tuner i would just be patient, thats could certainly be the issue

[DRIVER_R32]

When my r33 gts25t was doing this is was leaking at the charge pipe connects to the "over the top" plenum(intake throttle body) the clamps were lose and i was running -10.0-12.0 a/f
thats what i can say .. Boost leak under pressure.. Just a thought... Whenever ive heard a problem with turbo cars it is 90% boost leaks

[Skym]

I agree, pressure test intercooler, etc via compressed air -

http://www.youtube.com/watch?v=atretf9u-Mc

Coolant temp sensor for ECU can cause what you are describing (check via multimeter or oscillioscope, depending on sensor you are checking at sensor, as sometimes is not out by enough to trigger error code on ECU and same with any sensor on engine), so can switching to knock maps (if tuned that rich at idle on knock fuelmap). MAF can playup with airleak just behind it (missing sound, similar to coilpacks), but if dirty the hotwire is cooled less by incoming air which should result in lower voltage to reheat hotwire, so should run leaner (select lower load cells on fuel, ignition maps). But be aware that there are fake Z32 MAF's floating around and they cause problems.

Also check for wiring that might be grounded to chassis or loose in the plugs to and from sensor plug, ECU plug (it does happen with TPS if you accidentally knock wiring and engine can stall or stumble).

Another thing is check that ECU is in run mode (screw on side of ECU), not diagnostic mode.

Also the Nistune board could have dislodged itself from socket which result's in ECU switching to limp mode, running engine rich. But shouldn't be able to access consult when that happens.

Correct sensor voltages should be mentioned in manual -

http://www.jpnz.co.nz/afawcs0131170/CATID=24/SUBID=273/page=1/products.html

[blackdeath]

tkx for the replies guys , i am licensed tech and own my own shop, so these checks all have made .so its not like i flying blind ,.. skym ur comment about the maf fakeness is where i have been thinking but more like faulty or off ,but voltage at idle is still the same as it was when on dyno and was running at 15 on idle . coolant sensor is reading exactly the same as my temp gun, its not a vac leak or exhaust leak unplugging o2 doesnt make a diff

[Skym]

A way to eliminate MAF as a cause, is to unplug MAF when engine is off and start engine (stock ECU can run without MAF, but engages a revlimiter at around 2500-3000rpm and uses a preset load value. Same can be done with o2 sensor) and see if the problem stops. You'll need to clear MAF error code afterwards via Nistune. Also it's a stock ECU only feature, so doesn't work on aftermarket ECU's.

Fake Z32 MAF's usually don't have a Nissan logo on MAF housing.

[blackdeath]

cool ill check it out tkx

[ToroGTS]

I had a similar issue that was the result of small vac leak at the injector o-rings. I did notice a slight fuel smell and some wetness around the o-rings after going for a boost.