P0102 Fault Code

[Robert63]

I have a 04 plate 2.2 Zed which has developed a P0102 Fault Code. The engine rev counter fluctuates from 500 rpm to 1000rpm on idling regularly every second or so and its impossible to drive. I have replaced the Mass Air Flow Boot, which had a tear on it . I have cleaned the air filter, and cleaned the MAF sensor with MAF sensor cleaner. I am able to reset, and clear the code but when I start the engine the code comes back. I have tried running the engine with the MAF Sensor unplugged and the engine runs the same as with the sensor plugged in. Is there anything else I can check or am I looking at a new MAF sensor. Many thanks for all your advice as always.

[Smartbear]

If it doesn’t run better with the maf unplugged then the maf isn’t the issue.
Rob

[Chippie]

I would have thought if it runs the same with the MAF unplugged then the uneven idle would be caused by something else, although that doesn’t necessarily mean there isn’t a fault with the MAF, I’m sure there will be others that can offer better advice

[ph001]

It doesn’t sound like the MAF is the problem if it’s just the same with it unplugged but a P0102 code is nearly always the split concertina hose or the MAF. If you are sure the hoses are all good I think I would be buying a new Hella or Bosch MAF from ebay.

Do the revs change when you press the brake when idling by any chance?

[colb]

Have you checked the condition of the air filter, clogged airfilter can restrict the airflow to the Maf.
Good guide to diagnosing here https://www.autoblog.com/2016/03/12/p01 ... Q__miU2lGC

Just noticed you say you cleaned the air filter, is it a standard filter or have you a K&N oiled filter on it, if its a K&N and too much oil has been put on it will kill the Maf. Having said that double check you have no further air leaks if you replaced the intake bellows with a new one because of a tear in the old one. Also clean out the Idle Control valve with carb cleaner, they can gum up and stick causing bad idling.

Air leaks are sometimes difficult to trace, best option is a smoke test, traced an air leak on another members 2.2 to a crack in the plastic cam cover around No4 plug well. If you have dfiagnostics capable of looking at the fuel trims have a look and see what they are doing, high fuel trims will indicate an air leak either due to leaks or misreporting Maf.

[Robert63]

Excuse my ignorance but how do you do a smoke test ???? although I have got a small oil leak which drips on to the exhaust manifold just noticed it recently could this be where the air is getting in ???

[colb]

Yes that leak could also let air in, best renew the gasket as soon as you can to button it up.
a smoke test is carried out by generating smoke and pumping it into the vehicles intake from the engine side of the Maf to avoid introducing any contaminate onto the Maf sensor. I made my own smoke tester using a large new paint can and wired a 12v resistance wire coil around a wick. The wick gets soaked with baby oil and when power is applied to the coil it heats the wick enough to burn the oil, the resulting smoke is pumped via a small hose into the air intake on the engine. Smoke will make its way under pressure all the way through to the exhaust. The pressure I apply to mine is from a cycle air pump which produces enough pressure to do the job. If you have air leaks you will see the smoke appear from where they are.
Some videos on youtube if you search smoke test here is one much the same as my kit.
https://www.youtube.com/watch?v=Np_duzsaZxI

Just changed my cam cover gaskets, thread here viewtopic.php?f=3&t=120778
When you change the gasket also change the rubber seal washers for the cover securing bolts, they go hard with age and need to be soft to compress when you tighten the cover bolts.