M52 diagnostics code advice - 68

[miles25]

Hi,

After using the INPA diagnostics to try and get to the bottom of a lumpy idle on my E30 M52 I got the following codes:

68 Tank Ventilation Flap
52 Muffler Flap

Any advice as at first glance these seem irrelevant to my issue?

Thanks

[TSM3]

Hi,
I have the tank ventilation code on mine as well and been told it's irrelevant as the e30 doesn't have one. I think it's the same for the muffler flap one as well.

[rich318i]

all is good nothing to worry about

[DanThe]

Hi,
I have the tank ventilation code on mine as well and been told it's irrelevant as the e30 doesn't have one. I think it's the same for the muffler flap one as well.

This is correct, even with the fault codes it wont affect the engine running at all

[miles25]

Thanks all, I'll keep on the hunt for the slightly lumpy idle. It did actually seem better after just clearing all the stored fault codes.

I need to do a proper check for air leaks etc but wanted to see if it threw up any codes as a first port of call.

[Brianmoooore]

If, like me, you like to have an engine that throws no fault codes, a couple of appropriate resistors connected across the relevant wires will fool the ECU. BMW even produce one that plugs straight into the tank vent connector, that was fitted to cars that went to places that didn't require a closed circuit fuel tank.

[miles25]

Thanks Brian, I'll have to look into that as it would be good to get a fault free read out.

Out of interest do you work on E30's as a business or is it just a hobby?

[M1ke30]

Tye checking the earth straps. Does it take a few goes to start? Or hold back under heavy load??

[miles25]

Just to complete the thread, the lumpy idle was a faulty MAF. I had cleaned it but it made no difference, but after trying most other things (air leaks, ICV etc) I bought another genuine second hand MAF and it cured it.

It's interesting that the diagnostics only shows a MAF fault code if the MAF is not connected (or not detected) and not if the sensor is faulty.

I also got codes 202 and 203 Fuel Trim Bank 1 and 2. This turned out to be the Lambda sensors plugged in the wrong way round (thanks Danthe for the suggestion).