Group Captain Smudger

MY97 UK, 58K, recent induction kit
(I removed the "inspection panel" from the small box on the side of the MAF assembly, the one held on by four small screws. It took a bit of force to get this off. Was this a sensible thing to do?)

Symptoms began a few weeks ago with kangarooing when being less than gentle with acceleration. Last w/e tickover at start-up from cold was erratic. It managed to tickover at almost 0rpm, albeit rather lumpily, but as the accelerator was blipped the engine died. It was also a bit smokey at this stage (backbox has gained a nice sooty rim). Refitting the standard airbox & filter seems to have helped (certainly regarding the tickover). Last night unplugged the MAF and the engine immediately stalled. This morning whilst "going for it," the dreaded pogoing returned. PFR6Bs fitted last month. The filament in the MAF assembly looks OK. AFAIK it has its original lambda sensor.

What's going on? Or is it simply a case of the ECU not knowing whether it's coming or going.

GcS

The_Judge

Not quite with you here. Did you remove the whole MAF housing? Why? Did you put it back properly...?

The symptoms you've described certainly sound like they're either MAF or lambda related. You've tried one of the MAF tests. You could try the other 2...

- with a warm engine idling, rev it to somewhere above 3000rpm, then come off the throttle and watch the revs drop. As they approach 1200rpm, they should slow down, and fall smoothly to around 800rpm.

- reset the ECU and see how the car idles and drives immediately afterward.

If your lambda's the original, I'd be amazed if that was still healthy. Without an AFR gauge, there isn't much you can do to test it really...

Group Captain Smudger

Not quite with you here. Did you remove the whole MAF housing? Why? Did you put it back properly...?

Yes whole assembly removed and put back properly I believe.

It's the small "box" on the side of the MAF (it might be where the part number is stuck on). It's got three electrode type thingies (technical term) inside. As to why, good question, I was just being nosey I suppose - but wish I hadn't been.

I await your response with some trepidation, but give it to me anyhow.

Cheers.

The_Judge

You on about the part on the outside that connects to the part on the inside...? Doesn't that simply un-clip (if I'm thinking of the right bit)? Anyway, I think the point I was trying to get at was did you put it all back, or did you try running the car without the MAF sensor...!!!

I'll reiterate the points I made above...

The symptoms you've described certainly sound like they're either MAF or lambda related. You've tried one of the MAF tests. Try the other 2...

- with a warm engine idling, rev it to somewhere above 3000rpm, then come off the throttle and watch the revs drop. As they approach 1200rpm, they should slow down, and fall smoothly to around 800rpm.

- reset the ECU and see how the car idles and drives immediately afterward.

If your lambda's the original, I'd be amazed if that was still healthy. Without an AFR gauge, there isn't much you can do to test it really...

Group Captain Smudger

Thanks for replying. No it's not that bit, "my bit" is screwed in. Car has not been run w/o the MAF sensor.

Symptoms this morning were worse. Big belch of smoke from the bb and engine kept on dying. The misses reports that the "check engine" light was coming on all the time yesterday regardless. I'm worried I may be damaging the engine someway? Will try your option two tonight.

The_Judge

You could also connect the black connectors and find out what the CEL error code was...

vindaloo

Sound like my mate's TT. His coilpacks died! I'd break'n'make all of the connections on the HT side of things. Make sure the plugs are tight whilst you're at it. If it's that lumpy, I wouldn't drive it in case of ££££s bills to fix it.

J.