2000 Pontiac Grand Prix GT Mass Airflow Sensor
So today I was cleaning my car and cleaned
my mass airflow sensor. Ever since I got
the car the engine rpms pulse and I get
around 15mpg.I used the mass airflow
sensor cleaner, and then unplugged the
Manifold air pressure sensor hoping that
could help me figure out if either the MAF
or MAP were bad. After I unplugged the
MAP and i was reparking the car, it just
died. I know that it can run on just one or
the other so it would mean that the MAF is
bad. Right? I plugged it back in and its fine
now so my question is what does this
mean? Does it mean my MAF or MAP are
bad? Or are neither of them bad and its
something else? Thanks everyone
plug them both in and run the car. scan the computer for codes. there are test procedures for both sensors. check out you tube, or easyautodiagnostics .com
Mike is right. Autozone can scan your car for free. Plug everything back like its supposed to be, unhook the battery for 10-15 minutes. Hook it back up, go drive it around for a while until the codes come back on. Then go get it scanned.
The check engine light isn't on
How can it not be on if your unplugging the MAP and MAF sensors while its running.
I would still do the procedure trans am outlined and then scan for codes. There can be codes stored.
Thanks Mike. Bbaattllee when you turn your car to the run position, not crank, does the check engine light come on in the instrument cluster?
Just from memory Im pretty sure it does but I cant check right now. Are you suggesting that the light may not be working?
And when it died earlier it started with just the MAF plugged in and the MAP unplugged,then died less than a minute later. I didnt unplug the MAF
Plugging and unplugging sensors only rarely diagnoses a sensor problem. When you take something out of the equation then the computer tries to compensate and strange things happen. Best to follow the procedure above.
Yes there is a possibly its blown or more likely been removed if you don't see it on every start up.
Could I just unplug the maf and only use the map?
No the ECM needs input from ALL the engine sensors. That's why they're on the engine.
But I thought most cars only had either the maf or the map so why does my car need to use both?
Nope. One is mass air flow. The other is manifold absolute pressure. Maf is before the engine and map is in the intake.
Ok so i unplugged the maf this morning and the rpms are still bouncing... should i unplug the map as well?
No! Plug everything back together, unhook the battery for 10-15 minutes, hook the battery back up n go drive the car. Go to Autozone have them read the codes. Did you check and see if your check engine light is working?
I didnt get a chance to check if the check engine light was on but its been sitting with the terminal unhooked for 15 mins. Im about to reconnect it. Should I drive it right after I reconnect it?
I drove it around for around 10 mins while the engine was warm and the bouncing is 95 percent gone. Oh and I didnt see a service engine soon light come on at all
That's good. Did the check engine light come on when you first started it up? Its supposed to come on for a few seconds every time you start it.
And still not getting better mpg... does it just need more time since i just reset it?
No I didnt see it come on at all
Ok the gas milage readout can be reset. In town the car should be getting about 19ish mpg. As far as the service engine light it should come on every time you start the car. If its not get it fixed and I would still get the car scanned to see if it does have any codes.
Ok when it was bought it was getting around 20 mpg from the previous owner but im only getting around 13- 15. I do drive about 2 miles to school and 2 back every day though and those are most of my miles and my engine is cold most of the drive. I know that the engine cold gives less efficiency but would it effect it that much?
Also on the way home im sitting in traffic for about 5 minutes just to go around 1/10th of a mile but after that its straight home.
In the winter it can effect it that much. When was the last time you gave it a good tune up? Plugs, wires, fuel filter, pcv valve. Did you checkin see if you have a check engine light on start up?
No the light does not work. How do I fix it?
Take the cluster apart and put a bulb back in it.
No clue how to do that... and is there a chance that it could be something else besides the bulb?
If you are handy with a soldering iron, its not hard. There are some good YouTube videos on it. Also, did you ever scan the computer for codes?? Even if the light in the dash is out, the computer should still store a code. And btw Trans AM is right you can lose a lot of mileage in the winter especially on short hop driving.
Yes a broken wire. If you can't do it yourself find a mechanic who can.
Hey mike thanks. You don't even need a soldering iron. His gp has the bulbs with the plastic ears on them. Just need a small flat blade screwdriver once the cluster is out
Ok thanks guys
http://www.grandprixforums.net/thr eads/90349-97-03-Cluster-Gauge- LED-Install so i didnt find any videos but i did find this. If i follow what they do i will reach the ses bulb on the same cluster right?
Where can i buy a bulb at?
GM dealership, NAPA, electronic store(radio shack)
http://www.rockauto.com/m/mobile catalog.php? carcode=2002540&parttype=2812&a =Ad%2BCode%2Bwildaboutcarshow norcal&ck[ID]=0&ck[idlist]=0&ck[view currency]=USD&ck[PHP_SESSION_I D]=cp12g6kaqu4rrgbormn3de64k1 If you scroll down to 3.8v6>electrical bulb and socket>instrument panel bulb, do all of the bulbs fit and work for the ses light?
Ok... I got the bulb which was burnt out and now the ses light turns on when i start it, but its not on when running.... so that kinda sucks. Could it be possible that it has a code but the light isnt turning on for it?
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