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faulty MAF issue?
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Old 24 May 2014, 06:21 PM   #1 (permalink)
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Unhappy faulty MAF issue?

Do I have a faulty MAF?

I recently had the car remapped by Andy Forrest and he told me to replace the MAF as it was showing early signs of failing as it was just within tolerance.

Car is a MY99 Turbo 2000, It has the standard air box with a Green cotton panel filter installed.

Just installed brand new MAF, reset ECU and noticed that when using clutch control in 1st it nearly stalls and I have to blip the throttle. Also when engine is warm and idling around 700-800rpm every so often there is a sound that is like a misfire or popping noise.

When I disconnect the MAF (engine turned off) then restart the engine it idles perfectly no misfire or popping noises.

When parked up and reving the engine both MAFs make no noises.
When driving and on the move both MAFs cause no issues its only at junctions the new MAF seems to make the revs drop below 800rpm when pulling away.

I have logged the voltages of both MAFs:
Old MAF
1.04v when engine is cold and ignition on.
1.22v - 1.42v when engine warm and idling at 800rpm
1.04v when engine is warm and ignition on.
3.64v - 3.9v under load (18psi boost pressure)


New MAF
1.02v when engine is cold and ignition on.
1.18v - 2.22v when engine warm and idling at 800rpm
1.02v - 1.04v when engine is warm and ignition on.
3.96v - 4.04v under load (18psi boost pressure)

thanks in advance.
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Old 26 May 2014, 08:24 PM   #2 (permalink)
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Re: faulty MAF issue?

Not sure if this is caused by the MAF, when I started the car the revs struggled and stayed around 300rpm for about 1 or 2 seconds then shot up to the normal 1500rpm.
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Old 29 May 2014, 02:07 PM   #3 (permalink)
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Re: faulty MAF issue?

easy test with engine running unplug maf,car should stall...= maf working...

if irractic tickover,normally down to a failed or failing 02 sensor..
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Old 29 May 2014, 07:02 PM   #4 (permalink)
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Re: faulty MAF issue?

Quote:
Originally Posted by The Pilot View Post
easy test with engine running unplug maf,car should stall...= maf working...
I have heard of this test before and used it in the past and it didn't prove anything.

Quote:
Originally Posted by The Pilot View Post
if irractic tickover,normally down to a failed or failing 02 sensor..
The problem with the revs sticking for a few seconds has only happened once.

I have mentioned the voltages from both MAF's to Andy Forrest and he has confirmed that the new MAF is faulty because it should not be reading anywhere near 2.22v with a engine up to temp and idling at 800rpm it should only be no more than 1.22v. Its getting replaced.

Thanks for the reply.
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Old 05 Jun 2014, 05:47 PM   #5 (permalink)
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Re: faulty MAF issue?

Fixed, fitted replacement MAF, the idle and clutch control is spot on.
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