Erratic Idle

[dutchgold92]

On my (rather wet) drive to work this morning, idle was very rough and the engine cut out a few times in traffic.

 

My first concern is the MAF... Since fitting a pair of K&N panel filters (together with exhaust, but I doubt it's that), the idle speed has been less stable - but not this severe up to now. Could they be letting water or oil into the MAF? I also noticed at the time that there's a pencil-sized hole through the mesh on the MAF :huh:

 

I have driven in wetter weather up to now and hadn't noticed idle being any more erratic in the wet.

[jimmer]

damp weather and performance filters can often be a problem for maf sensors,unplug the maf and see how it idles after,its a very easy well to tell if it is the issue.

[dutchgold92]

damp weather and performance filters can often be a problem for maf sensors,unplug the maf and see how it idles after,its a very easy well to tell if it is the issue.

 

Will try that, thanks. If that's the case is the MAF likely to be knackered or could I clean it off and revert to OEM filters?

[jimmer]

Will try that, thanks. If that's the case is the MAF likely to be knackered or could I clean it off and revert to OEM filters?

maf can be left to dry and a shield of some sort can help the issue if it is that,They came with a shield behind the bumper from new but many have been removed over the years.

[Gaz 300]

Hate driving my Z in the wet with my HKS filter as it can start to fart about. Need to shield it better or might remove it for one that sits higher up.

[dutchgold92]

Hate driving my Z in the wet with my HKS filter as it can start to fart about. Need to shield it better or might remove it for one that sits higher up.

 

I'll definitely be going back to OEM filters if this is the issue. Not worth it for a stock NA engine I think.

 

It has had slightly erratic idle even in the dry though since fitting these filters.

[Gaz 300]

I'll definitely be going back to OEM filters if this is the issue. Not worth it for a stock NA engine I think.

 

It has had slightly erratic idle even in the dry though since fitting these filters.

 

I was in Richard's Z on the way home from the Coventry show when we had the worst torrential rain I have ever seen and he had an apexi filter fitted and had no problems driving through heavy floods. So its all down to the installation of them Jay.

[dutchgold92]

I was in Richard's Z on the way home from the Coventry show when we had the worst torrential rain I have ever seen and he had an apexi filter fitted and had no problems driving through heavy floods. So its all down to the installation of them Jay.

 

May be oil more so than water - this thread sounds very familiar. I wonder if he kept the K&Ns in the end?

[dutchgold92]

Idle was still a bit off on my dry drive home yesterday, but nothing so extreme. Pulled out the air box when I got in and there was no sign of water, but there was about as much oil as DJ_Party_Favor found:

 

 

Cleaned out the box and MAF - to be fair the MAF wasn't cleaned when I changed the filters before, and by now it was fairly dirty. Put the K&Ns back in but will be keeping an eye on them.

Very wet again this morning but no issues. Idle was steady the whole way, starting at around 950RPM once up to temperature, then dropping to 900 and 850 as the journey went on.