WICruiser

Any chance that the mouse nest was made with wiring insulation from your MAF wiring harness?

Bill Ball

Nobody going to second my O2 sensor suggestion?

John Speake

Hi Bill,
As the car only ran for 10-20 seconds before going rich after a cold start, then I think that is too short a time from the O2 loop to take over. The temp 2 water temp has to be at least 60deg C.

Some Bosch MAFs had a fault where they will suffer thermal runaway. This can happen as quickly as 20 secs.

I suugest to kgrimshaw that he removes the engine airfilter to observe the MAF hot wire assembly. Then switch on the ignition - no need to start the engine.

If he sees the wire starting to glow orange/red after 20 seconds or so, that confirms the diagnosis.

This is much easier than removing the MAF to get at the connector, although that is still a possible cause of the problem.

Jim bailey - 928 International

Generally the oxygen sensor input is a relatively minor adjustment of the mixture not such a profound over rich condition as described .

John Speake

That's true the O2 loop has an adjustment range of +/- 20%.

MAF sounds more likely, but maybe a good idea to check out the temp2 sensor as well.

SteveG

+1. I'm also wondering where you found the mouse. Are you using "Galley" to describe valley?? You can't have seen the valley w/o removing air box, cant' really see much then. Ignor following if you have. IIRC you have Temp I connected to air box, so remove two nuts holding air box, loosen connecting boot from box to MAF, gently remove box. then you will see MAF and elec connector. Are screens in place at ends of MAF? Don't touch the platinum wire. That is what should glow after 4 seconds of ignition on. HTH

Bill Ball

OK, fair enough. As to the delay being too short....if the sensor were already partially warm, it could be short. I see variable times before my A/F meter starts cycling depending on how long that car has sat. If cold, a minute or more; if warm, right away.

PorKen

Is this the same for 2.2 and 2.3?

John Speake

That last statement might cause some misunderstanding. Only when the engine has run above 2000rpm and the water temp is at normal operating temp will the hot wire glow briefly about 4 secs after igntion switch of.

The test I recommended for thermal runaway would show (if MAF faulty) the wire continuously glowing as long as the igntion is on, with engine stopped, temperature not relevent.

John Speake

Yes

kgrimshaw

Thanks to all.

Have not completed the diagnosis. Just got home from work. The mouse made a mess of the valley and yes I had the MAF out before I posted on the list. While my wires and connectors are not in real good shape (old and brittle) i cannot see any teeth marks. With the MAF back in, ignition on, engine cold...no glow. I waited 2 minutes...no glow. Started the car, it died. I then turned the ignition back on, checked the MAF... no glow. Do we have a sign?

John Speake

You won't get the 1 second glow unless water temp has reached normal running values (80degC or so).

Try disconnecting the MAF to force the LH into limp home mode. The car should idle reasonably when it warms up a little. At least then you can check for black smoke.

To determine whether the O2 sensor is a problem, disconnect the battery gound strap, unplug the sensor, reconnect the battery and start the car. This will force the LH to recognise the O2 sensor is disconnected, and it will then set itself to mid range fuelling.

Let us know how you get on.

AO

Kirk-

If you need a spare MAF to test, let me know. I;ve got an extra you can use to trouble shoot. Just let me know where to send it. BTW, are you coming to Hell?

kgrimshaw

You are the man...

Yes, Please.. i would like to try your MAF. If it is the problem and i can get a replacement in time, i will see you in Hell!

Thanks Big Time

Kirk Grimshaw
4315 Pulte Drive
Marne, MI 49435

616-460-0519

AO

OK Kirk,

I'll try to send it tomorrow.

Cheers,
Andrew