New MAF installed, motor wont rev above 2500rpm


Old 08-04-14, 12:22 AM
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New MAF installed, motor wont rev above 2500rpm

I have a Ford Windstar 3.0.-00.(enginecode U) It ran very rough on idle and there vere black smoke from exhaust. Got ODB-codes from maf, circuit to high and to low, stored codes. Replaced the MAF and that problem went away. Cleared the codes also.
Now it runs fine up to apx 2500rpm, after that it wont go any higher.
No new odb-codes, but i get "fuelsystem 1 OL_FAULT" on my reader.
Will change fuelfilter as a first step, what else can it be? Before I replaced the MAF it was no problem to rev the engine to higher RPM's.

After replacing the MAF, the onboard computer says the van uses apx 7l/10km fuel! Very wierd, Tried disconnecting the MAF and the fuelconsumtion drops and the engine will rev again, but it runs horrible and misfires without the maf connected.

The new MAF is reading apx 5g/sec, and I believe thats normal on idle?

I prob. have forgotten something of importance, so don't hesitate to ask!

Really need your help guys!
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Old 08-04-14, 06:25 PM
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Misfires and rough idle - Ford F150 Forum - Community of Ford Truck Fans

Both are Fords, so it's close enough to your car. OL is open loop fuel fault. It simply runs out of fuel at higher RPMs.
Old 08-04-14, 08:28 PM
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new does not always mean good. try another maf.
Old 08-30-14, 11:52 AM
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I agree with iceman, especially if "new" actually means "reman"... VERY likely the MAF could be defective. Also there the @ idle grams per second is not a good indication of much, to properly test a MAF sensors function you need to be wide open throttle... you need RPM, elevation, barometric pressure, maf reading in g/sec off the top of my head and there are free calculators online you can find to plug that data in and it will tell you approx. what the vehicle should be reading and what it is reading and many will give you a red or green if it is good or bad. If your scanner cannot graph data and go back and pull the same point from all data plots then don't waste your time with this.

Another common indicator of a faulty ford maf is if the Hz reading is below about 155Hz or so. Again, a cheap scanner may not show this information but it is a data pid on a decent scanner.

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