Nissan Primera C.O Problem

[brad6271]

I have a 1999 2.0 Ltr i Nissan Primer Estate.

At its last MOT it failed on very high C.O levels at idle speed (6.8 compared to 0.3 which it should be).
At 3000 revs the C.O is exactley what it should be and the car runs like a dream.

At idle the engine revs fall to almost stalling point about every 30 secs and then the C.O readings go up to 9.5. This to me shows that the engine is getting a burst of fuel for some reason.

It has been taken to a very good Nissan main dealer (who I trust) who as of yet have not been able to trace the cause.
They have checked the ECU and run diagnostics on all related sensors, several sensors have been replaced even though the diagnostic equipment showed them to be working, injectors have been tested, spark plugs have been changed and fuel pressures checked, the list goes on and on.

The technicians have contacted Nissan technical support, they could only go over what the Nissan dealer had already done and agreed that the problem should be down to a sensor like the oxygen sensor.

I now have the car back with the problem still not fixed. I am losing the will to live and have thought about trading it in, but lets face it what dealer is going to give me good money without an MOT.

I am hoping that there might be somebody out there who has seen a simular problem or can think of what might be the cause. Theres no harm in trying.

If you think you can help please respond to this.

Thanks

Brad

 

[MANDATE]

I can't help you but, I suggest you try the forum on www.carmachanicsmag.co.uk, I'm sure you'll get some response there.

 

[jonnyfishing]

Brad

Sounds like a tricky one if nissans can't solve it.Whenever I have problems with idle speed, I turn to the "idle speed control valve" also known as "idle air control valve".If this has not been looked at,try cleaning or replacing it.This will not always generate a fault in the E.C.U.but if faulty or dirty(sticking)it will give you erratic idling and high C O readings,Hope this helps

John

 

[steve_s46]

As you say it sounds like its running rich - but i would have thought something as bad as that would throw some kind of fault code. Have you tried looking at the igniton side of things - plugs/leads/coil/dizzy etc etc? Could be that youre getting a weak spark/no spark which would explain lumpy idle and partially burnt fuel in the exhaust. Sometimes ignition faults arent noticed by the ecu because it sees current is flowing so assumes all is ok, but it could be arcing to earth somewhere and not reaching the plug. Can you seen any black smoke or smell fuel from the exhaust?

 

[philiphales]

I hope by now your fault is cured, but you should have joined the Nissan Primera Owners Club - just enter NPOC into Google.

 

[adammills]

Did you manage to solve it and if so how?

 

[breezer]

Did you manage to solve it and if so how?

adammills, please read the forum rules.

brad6271, who started this thread asked nearly 3 years ago and only made the one post (give away is the post count) it is most unlikely you will get a reply from the OP