I am looking to understand my car failure, is related to the MAF SENSOR : iF I START THE ENGINE WITH OUT THE MAF SENSOR CONNECTED, THE ENGINE RUN PERFECTLY, with an average of 30 mpg, the down side , the cooling fans are constantly turned on ,even after turn off the engine, When i plug the maf, the engine is unstable, rpm vary and can smell the unburn fuel
i bought a new sensor, and ran fine just 1 start cycle, if you had this experience,please help me as i spend on tecnicians and dealer mechanics and even replace the harness, same result.
Without the MAF sensor plugged in, the computer uses a default value in place of the MAF sensor signal so the engine will still run.
The MAF sensor is basically a hot wire anemometer. This means a current is applied to the wire to heat it up and the amount current that’s applied to keep the wire at a constant temperature allows the computer to determine how much air is entering the engine.
Since a current is being applied to the MAF sensor, there’s a fuse and a relay in the circuit.
The fuse for the MAF sensor also supplies current to the O2 sensor heaters, Intake Air Temperature sensor, and fuel compensation sensor. So, if that were the problem the Check Engine light would be on with codes for those systems.
I would then look if there’s a bad relay for the MAF sensor circuit.
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will look for it, as the maf sensor flow appear as good on the scan tool, will look again for the fuses, this is notorious on the cooling fan speed, this may solve a 1 year problem, in my car maf must be connected to use the cruise control, i turn on the engine with the maf unpluged,waith till the fan start and reconnect.
Your cars PCM (computer) needs to relearn the new MAF sensor and during the relearn, the engine can run rough at times. You can shorten the relearn by disconnecting the negative (ground) lead from the battery for about ten minutes. This will clear all the old data and force the computer to go into the relearn procedure.
It can take up to twenty minutes or more after the vehicle is up to operating temperature for the relearn to take place. If you have access to the factory service manual, there is a procedure to make this relearn happen quicker, but for most of us, the best way is to go for a drive at between 40 to 60 miles per hour (68-100 kph) for about 20 minutes or so.
Did the dealer not provide a parts and labor warranty on the MAF?
knucklhead diy’er here, no buick experience. there might be a problem with the coolant temp sensor. the coolant temp is an important input to the powertrain computer’s air/fuel calculations. that could confuse the computer, make it inject too much or too little gasoline, and this could cause the engine to misbehave even if the maf is actually good. ask your shop to verify the coolant temp is being sensed accurately.
With the maf unplugged the computer may not use the coolant temp data as an input.
If it turns out this is indeed the problem be aware the catalytic converter may have already been damaged & need replacement.
Hi, i use hand held scan tool, maf is good, on this 3.6 VVT, the computer handle and adjust ( i even can read the timing changes ) the rpm maintain at 2000 and then gradually self adjust, my first indication of a problem was the cooling fan speed control, if the engine is used with the maf not connected, the fan will keep on after the engine is turned on, i read the last recommendation and remove the fuse, was corroded, fuse box has moisture, not too bad to be replaced, after reinstall all the fuses the car turn on and drive correct, now the low rpm is changing , but no engine stall or unburnt fuel smell, after a long drive rpm is steady on idle ,
Is this the engine bay fuse box that has moisture?
If so, is the cover in good shape?
Yes, i bought this car and had engine fire, i rewire all the damaged wires, on the engine area fuse and relay box i found ,in the fuses terminals a white powder , i remove and clean all the fuses and apply wd40 , now car looks like learning, before of this fuse revision, engine if was used with maf sensor connected at the first start, the idle never was stable and even stall.