Idle issues, :(

[JDMicra]

Hi all.

My Super S is idling really low. When I start from cold, the idle is just below the first mark above 0 on the rev-counter (300ish rpm I'd guess) When she's warmed up, idle goes up to the second line and a bit higher. Its annoying as I have to rev the car quite a bit to get out of my garage as its on a slope, then she dies on me (still cold) and won't start for a couple of turns.

Any ideas? Can I just increase/reduce the air from the throttle body, or is it something more serious?

 

[pollyp]

I'd say from experience its its a common problem caused by series of events:
1. old seized coldstart waxstat mechanism stuck in fast idle mode when warmed up so...
2. idle speed bleed screw is usually tightened too much to compensate, which makes it cold idle or coasting down in neutral rev too low/stall if...
3. IAVs sticking/misadjusted so the ecu can't electronically control the idle airflow enough hence the idle's too low or irratic

so solution is to remove the faulty waxstat mechanism, clean & align the IAV, adjust the idle screw till it warm idles at 750rpm and cold idles at 1300rpm

wrote a guide
http://micra.org.uk/threads/how-to-configure-the-iav-idle-speed-with-nissan-datascan.43069/

 

[JDMicra]

THanks again pollyp, I keep getting message that I dont have the permission to view thread for some reason though, even though I'm logged on :/

 

[pollyp]

Need to be a member to view the diy guides section

 

[pollyp]

I've updated it to my blog page 19 post 908

http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-19

 

[Revmau5]

Hmmm, i had a similar disaster this morning.
Started Micra, had very low petrol...was a bit dodgy to the petrol station. < Lol
Started cutting out, thought it was that low so i coasted in and filled it. Drove out, still cutting out though. Pulled over, checked the obvious input sensors... MAF, TPS... Nothing severely loose that i've noticed different over night.

I'm hazarding it's the MAF moreso that my IAV. Reason being i've throttle bodies and the IAV plays no part in my life except occupying a cable tie over near where the carbon canister was.

So my questions...
- Since i have no airfilter due to thottle body plenum, has my MAF got covered in road grime and stopped working? What are the voltage checks for this, and will it register on OBD?
- Or is it my IAV, which i don't use and is cable tied in my rather disgusting engine bay...possibly seized, probably broken?

Text A or B to 0800 LOW-RPM-IDLE

[EDIT] I should mention when i floor it, it cuts out at low RPM, if that helps?

 

[JDMicra]

::UPDATE::

Had a go at removing the waxstat but annoyingly all the screws are shedding their thread when I try to remove them, even with penetrating fluid. I've also tried taking the thing to 3 different mechanics, all giving different (yet expensive) reasons as to why its not idling normally. I should point out that a number of mechanics in Malta adopt a have-a-go attitude which is NOT what you want with your car. Anyway, as this is turning into a bit of a faf and the little micra is my daily driver, would I be ok if I just replaced the entire throttle body? The one I have looks a bit past it anyway.

 

[cts_k11]

Hmmm, i had a similar disaster this morning.
Started Micra, had very low petrol...was a bit dodgy to the petrol station. < Lol
Started cutting out, thought it was that low so i coasted in and filled it. Drove out, still cutting out though. Pulled over, checked the obvious input sensors... MAF, TPS... Nothing severely loose that i've noticed different over night.

I'm hazarding it's the MAF moreso that my IAV. Reason being i've throttle bodies and the IAV plays no part in my life except occupying a cable tie over near where the carbon canister was.

So my questions...
- Since i have no airfilter due to thottle body plenum, has my MAF got covered in road grime and stopped working? What are the voltage checks for this, and will it register on OBD?
- Or is it my IAV, which i don't use and is cable tied in my rather disgusting engine bay...possibly seized, probably broken?

Text A or B to 0800 LOW-RPM-IDLE

[EDIT] I should mention when i floor it, it cuts out at low RPM, if that helps?

Any updates on resolving this issue i seem to have a similar issue with my 1.0 standard lump tried driving with my MAF unplugged didnt help cleaned up my IAV still no luck. Equally this problem started when nearly in the red bit of fuel guage hehe also it revs up ok(lumpy on idle) till you start driving then dies once you hit the pedal
cheers

 

[karlj]

::UPDATE::

Had a go at removing the waxstat but annoyingly all the screws are shedding their thread when I try to remove them, even with penetrating fluid. I've also tried taking the thing to 3 different mechanics, all giving different (yet expensive) reasons as to why its not idling normally. I should point out that a number of mechanics in Malta adopt a have-a-go attitude which is NOT what you want with your car. Anyway, as this is turning into a bit of a faf and the little micra is my daily driver, would I be ok if I just replaced the entire throttle body? The one I have looks a bit past it anyway.

replacing the complete throttle body won't do any harm, any preface lift tb will do the job

 

[Revmau5]

It was my MAF. I've mounted it on the throttle body plenum and one of the small wires came lose after i resoldered it in place. Soldered it back up again and it was sweet!

 

[jacob_ts]

idle air control valves often get a lot of carbon deposits on them causing them not to operate, remove the iacv and clean with carb cleaner this will most likely solve problem, or if it runs rough all the time try the maf the earlier ones suffer from broken solder joints internally