Yet another 00553 fault code

[gmac78]

Alright gents,

A few weeks back my car started intermittently running rubbish, wanting to stall all the time. A quick scan showed 00553 and 00537. Cleared these and away I'd go until it started playing up again. More often than not it's just 00553 that's logged, 00537 comes in every now and again.

Carried out a boost leak, all good.

MAF is a reburbished unit from ECP, a few years old now, possibly around 8, however not done that much miles maybe 10-15k.
Lambda is about 3-4 years old with even less miles, maybe 2-4k.

I was having a read through this for MAF testing-

http://www.s2central.com/ds_G70.html

Basically from a quick check today between pins 1 and 5 I'm getting good battery voltage, around 11.75 with ignition off, with engine running around 12.5 volts.

I then turned my attention to pins 1&3. When the car is running fine with no issues I'm getting correct voltage at these pins between 2.5-2.6v, however when the car is wanting to stall etc there is no reading to be had across the same pins, just showing 0v. Also when engine is off and just ignition feed with no fault codes logged it's showing the correct 1.3v.

Does this sound like my MAF is goosed or should I be paying attention to the supply and ground wiring for these pins?

Cheers chaps.

[K Simmonds]

That sounds like an issue with either the MAF or the plug, I take it you've cleaned the connections and made sure they're making good contact?

[gmac78]

That sounds like an issue with either the MAF or the plug, I take it you've cleaned the connections and made sure they're making good contact?

Yeh MAF pins were replaced a few years back with the correct gold plated ones. Gave both male and female pins a clean anyway but didn't make any difference. Also one thing I've noticed it doesn't seem to do this from a cold start, once I've been driving for a while and got it up to temp, when I switch off for 10 mins or so and restart that's when it comes on, I've noticed this pattern quite a few times now. Strange!!

[K Simmonds]

Now that is strange. I'd have to check the circuit diagrams, but as it seems to be temperature related could it be the MFTS or it's connection playing up? I'll have to have a good think about this one as electrics really aren't my area of expertise, nuts and bolts are more my thing.

One thing you could try is when the cars running badly, unplug the MAF and if doesn't make any difference then I'd put money on it being that at fault.