Problems with MAF? or not...
#1
Problems with MAF? or not...
Alright so my ws6 was having idling problems, it would start up just fine but after a minute or so it would drop down to like 400 rpm and almost stall out. Also when i drove it, the rpms would be fine until i would come to a complete stop in neutral where again it would dip down to 3-400 rpm and struggle staying on so I would have to sit there with the gas pedal down.
Looked it up on the forums so I decided to unplug my MAF sensor to see if that was the problem. Surely enough it was and I had no problems whatsoever. This brings me to yesterday where i bought a new MAF, it was used but still working from a member on this site. Changed out the MAFs, plug it back in, and start it up fine. This time the rpms didnt drop in idle so I figured the problem was all gone.
But as I was driving it once again tried to stall out when i would come to a complete stop. Same exact thing as last time, I had to keep my foot on the gas to keep it from stalling and if I let go, it would drop right back on down to like 400rpm. I really dont want to take it to a mechanic so I figured I would ask here and hopefully get some more ideas as to what it could be. I assume this means my maf isnt bad but then it doesnt make sense that if I unplug it, it runs fine...
Looked it up on the forums so I decided to unplug my MAF sensor to see if that was the problem. Surely enough it was and I had no problems whatsoever. This brings me to yesterday where i bought a new MAF, it was used but still working from a member on this site. Changed out the MAFs, plug it back in, and start it up fine. This time the rpms didnt drop in idle so I figured the problem was all gone.
But as I was driving it once again tried to stall out when i would come to a complete stop. Same exact thing as last time, I had to keep my foot on the gas to keep it from stalling and if I let go, it would drop right back on down to like 400rpm. I really dont want to take it to a mechanic so I figured I would ask here and hopefully get some more ideas as to what it could be. I assume this means my maf isnt bad but then it doesnt make sense that if I unplug it, it runs fine...
#2
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Its a long shot but you could have a bad ground to the maf and it is causing it to short out. hence when you unplug it, it runs fine. Check your ground wires and sadly you might have to get a new maf. I wouldnt buy one unless you rule out everything else or you can return after installing if that wasnt the issue. i hope it helps.
::::EDIT:::: Okay so forget what i said previously. I done some looking around and called a mechanic that i know and the Maf shouldnt affect idle. It should only cause loss of power on take off and when you try to accelerate hard or under a load. If that is true then the maf is good. To be sure take it off and inspect the the probes on it and make sure both hot wires are A still attached and B that they are clean. If both are true then re install the maf and you can probably rule that out. Also check to make sure your plug wires are not arcing across the motor. I did happen to have that happen once in my olds 88 which is also the 3.8. It didnt throw any ses light but when i opened the hood with it running you could see the arc. I had no power going up hills and it ran rough. So make sure the plug wires are good to rule that out. Also is your car getting up to normal operating temperature? Let me know.
::::EDIT:::: Okay so forget what i said previously. I done some looking around and called a mechanic that i know and the Maf shouldnt affect idle. It should only cause loss of power on take off and when you try to accelerate hard or under a load. If that is true then the maf is good. To be sure take it off and inspect the the probes on it and make sure both hot wires are A still attached and B that they are clean. If both are true then re install the maf and you can probably rule that out. Also check to make sure your plug wires are not arcing across the motor. I did happen to have that happen once in my olds 88 which is also the 3.8. It didnt throw any ses light but when i opened the hood with it running you could see the arc. I had no power going up hills and it ran rough. So make sure the plug wires are good to rule that out. Also is your car getting up to normal operating temperature? Let me know.
Last edited by Jrclayton; 03-19-2014 at 10:19 PM. Reason: New Information
#3
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When you unplug the MAF it puts the car in closed loop/limp mode and doesn't take readings from the MAF, 02's, and IAC. It just runs on info from the pcm.
I had the exact same problem, chased ground wires, unplugged ****, pulled my hair out, everything. It turned out to be my O2 sensors, I replaced both of them and it has acted perfectly ever since. I would almost put money on that being the problem.
I had the exact same problem, chased ground wires, unplugged ****, pulled my hair out, everything. It turned out to be my O2 sensors, I replaced both of them and it has acted perfectly ever since. I would almost put money on that being the problem.
#4
When you unplug the MAF it puts the car in closed loop/limp mode and doesn't take readings from the MAF, 02's, and IAC. It just runs on info from the pcm.
I had the exact same problem, chased ground wires, unplugged ****, pulled my hair out, everything. It turned out to be my O2 sensors, I replaced both of them and it has acted perfectly ever since. I would almost put money on that being the problem.
I had the exact same problem, chased ground wires, unplugged ****, pulled my hair out, everything. It turned out to be my O2 sensors, I replaced both of them and it has acted perfectly ever since. I would almost put money on that being the problem.
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It may be different for your car, but generally it will be one of those three things with the symptoms you are describing. You've already narrowed it down with the maf. You don't really hear about IAC's dying much. Plus you said you were already throwing O2 codes right? Maybe they finally died completely.
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#9
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The idle dropping down when you come to a stop is either the IAC valve closing a little too much momentarily or the fueling is being cut down a little bit. But a few different things will cause the IAC to close too much. A bad cam position sensor can cause the fueling to act up.
I would get a scan by someone to see how the 02 sensors are switching while the engine is running and hot. Either they are failing or they are good.
I they are switching good..........you may need a new TPS or possibly a failing IAC. TPSs wear out......and that worn spot causes issues sending bad info to the PCM, which then tells the IAC wrong info so it closes too much at times.....or opens too much also.
Unplugging the MAF doesn't tell you anything. The PCM adjusts for that very quickly and the engine will run normal......and actually damn good. I drove around with an unplugged MAF with my 427ci for like 2 years because it ran so perfect. MAFs are used for two things.....1) Cold engine start up.....and 2) when you go WOT. They also do a little bit of help in fine tuning during part throttle driving....but mainly just the two things......
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