Thread: MAF FAULT POSSIBLE

Originally Posted by nigelbuilding1984

ok now this is wierd i got the car running sweet now i disconected vacum advance as when i sucked on it and it advanced the spark would cut out randomly on the timing light now disconected running really well so might be a faulty dizzy after all i suppose i did fill it with muddy water if this sounds like i could be on a winner any advice cheers so far

Try a GB864 rotor button off an XF Falcon as they have a wider contact arm which remains near the cap terminal for longer. Your standard button may be firing off one corner of the contact, I have seen this quite often.

ok now this is wierd i got the car running sweet now i disconected vacum advance as when i sucked on it and it advanced the spark would cut out randomly on the timing light now disconected running really well so might be a faulty dizzy after all i suppose i did fill it with muddy water if this sounds like i could be on a winner any advice cheers so far

Is the vacuum line blocked off when it's "running sweet"?

I thought the ignition came up good on the Sun machine. I would trust it more than a timing light.
A misfire here may cause a running rich fault. The O2 see's Oxygen in the exhaust and injects more fuel.

Just because you replaced the temps sensor does not mean anything to the PCM. If you have a broken, chaffed, dirty connection anywhere on that circuit, it will affect it.

Did you do any of these tests I asked?
Fuel regulator diaphram leaking. Not pressure. Unmetered fuelling.
O2 sensor output at hot idle and 2000rpm/hot. (scope, analogue multimeter). They should be cycling between 0.1V to 0.8V when operating correctly. This will tell us weather the PCM knows it's running rich or thinks it's lean and weather or not the O2s are shot. (although I doubt these are the cause but I suspect they're not helping).
MAF voltage. The MAF is a primary controller of fuel delivery. A little voltage makes a big differance.
Purge solonoid. Leaking? Unmetered fuelling.
Pin out voltages from PCM. What does it see. For example if the coolant temp sensor circuit has a poor connection the PCM will see a high voltage indicating it's cold. It will then throw in buckets of fuel. The only way you will know is measuring the voltage at the PCM or using a scan tool and looking at live data.
What test equipment do you have access too?

You saying it has come good a couple of times makes me suspect wiring. But that's just my stab in the dark.

I Dont know why the sum machine didnt show it up after speaking to mymate that did it he said it couls be possible as the machine was showing some strange readings but he thought it would be ok also the reg isnt leaking and im not chugging black smoke either the injectors are pulsing normaly again but as soon as i reconect the vac advance it must be trying to recover its self and the oxy senser conversion hasnt been done yet just got all the parts for it and when the temp sensor is disconected at operating temp it loads up with fuel reconect back to normal again so im guessing that is working my mates scan tool wont talk to landrover computer so we cant see the fault codes thanks very much for every ones help.

yay finally all fixed replaced dizzy and now every thing is back to normal and is running sweet yay

So what was wrong with it?