NickSchmaus
Observer
Your millimeter probably has a fuse in it you can replace, I've done this before
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MAF Sensor voltage issue 2004 Montero Limited
- Thread starter jasonsuperb
- Start date
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haolepinoy
Incomplete Idiot
Regarding these three:
1) 13-14 mpg is what i see with mine currently, unfortunately. According to my fuel trims I have an unresolved issue somewhere that is causing the car to run very rich (trims pegged at +25%, no up or down). Some have reported 16 mpg as an average, some have even claimed 19+ mpg...but people also claim to have seen bigfoot, so there's that. The 16 mpg number is probably where a healthy Gen3 will be. Your fuel trims are probably just as jacked up with this unresolved issue floating around. If you're skilled with the scanner you can check your bank 1 and 2 trims to see any hints to where your stoichio'mixup is.
2) The condenser fan, check this out, particularly the part about reconnecting the battery. If it goes off after the initial system recheck, you're good. It's only supposed to run when the A/C switch is on (or defrost) or if your coolant is hotter than it's supposed to be. You can read more about the normal operating parameters in the FSM 55A-3 thru 5.
3) Like Nick said, check for a fuse in your multimeter before chucking it in the bin. Hopefully that's all it is.
haolepinoy
Incomplete Idiot
According to FSM 13AC-9 thru 17, here are the things to test when receiving a P0102 Volume Airflow Circuit Low Input code:
1) Check the VAF sensor using a scanner. Test is performed with engine running and warmed up. Frequency should be around 10 Hz at idle, and increase with engine speed.
2) Check the B-48 connector with a multimeter. Tests performed with connector disconnected and ignition on. Power supply voltage (terminal #4 to ground) should be same as battery voltage. Sensor signal voltage (terminal #3 to ground) should be between 4.8 - 5.2v. Sensor continuity (terminal #5 to ground) should read less than 2 ohms.
3) Check the B-48 wiring harness for any issues (cracks in insulation, loose connections, etc.). Beyone a mere visual inspection, a good way to do this is to run the vehicle and have someone wiggle the connector and wiring harness, watching for any idle changes or frequency inputs on the scanner.
4) Check the PCM wiring harness for any issues...
5) Another thing to check is for air leaks between the VAF sensor and the Throttle body, like maybe a loose clamp or a split in the rubber or resonator thingy somewhere.
1) Check the VAF sensor using a scanner. Test is performed with engine running and warmed up. Frequency should be around 10 Hz at idle, and increase with engine speed.
2) Check the B-48 connector with a multimeter. Tests performed with connector disconnected and ignition on. Power supply voltage (terminal #4 to ground) should be same as battery voltage. Sensor signal voltage (terminal #3 to ground) should be between 4.8 - 5.2v. Sensor continuity (terminal #5 to ground) should read less than 2 ohms.
3) Check the B-48 wiring harness for any issues (cracks in insulation, loose connections, etc.). Beyone a mere visual inspection, a good way to do this is to run the vehicle and have someone wiggle the connector and wiring harness, watching for any idle changes or frequency inputs on the scanner.
4) Check the PCM wiring harness for any issues...
5) Another thing to check is for air leaks between the VAF sensor and the Throttle body, like maybe a loose clamp or a split in the rubber or resonator thingy somewhere.
haolepinoy
Incomplete Idiot
1) Regarding cleaning the MAF, be careful to read the label on whatever MAF Cleaner you are using...
For some reason not specified on the label our Karmen Vortex style MAFs do not respond well to chemical cleaners. I have no idea why, but it's written there in #10 on the second picture in case you missed it. Hopefully this did not damage your sensor.
2) Regarding the hunting idle, if your battery was low and needed to be recharged the PCM can view that as a similar state to being disconnected requiring the computer to relearn its idle parameters based on sensor inputs. The first thing that the FSM tells us to do if we have a hunting idle (up and down, erratic, unstable) is to determine if the battery has been recently disconnected (FSM 13Ad-36). If so, start the engine, let it warm up to normal operating temp, and then let it idle for 10 minutes before shutting it back off. This should clear up the idle inconsistencies if there are no other problems.
3) Regarding the MAF acting like it was disconnected (not the same as malfunctioning), in such an event the vehicle will actually revert to a fail-safe mode. The idle should stop hunting if the sensor is disconnected, running now on predetermined fuel maps. These won't be the most fuel-efficient maps for sure, and will likely be very rich.
4) Regarding your battery drawing down to 12.3v after a few days of driving. It seems odd that your battery is only showing 12.3v, even after regular drive cycles (and it being charged twice). A healthy battery should have no trouble holding at 12.7v even after a few days of sitting. Hopefully this is due to your parasitic draw issue and not a charging system or battery problem. Fingers crossed it is in your dome light and not somewhere behind the dash. Start with the simple, pull the bulb the same way you'd pull the fuse and see if the draw goes away. How old is your battery? How clean and tight are the terminal connections? How clean are the engine bay chassis grounds?
...sorry for the over-dump of info. It's probably not as helpful as I think it is.
jasonsuperb
Observer
1) Regarding cleaning the MAF, be careful to read the label on whatever MAF Cleaner you are using...
For some reason not specified on the label our Karmen Vortex style MAFs do not respond well to chemical cleaners. I have no idea why, but it's written there in #10 on the second picture in case you missed it. Hopefully this did not damage your sensor.
2) Regarding the hunting idle, if your battery was low and needed to be recharged the PCM can view that as a similar state to being disconnected requiring the computer to relearn its idle parameters based on sensor inputs. The first thing that the FSM tells us to do if we have a hunting idle (up and down, erratic, unstable) is to determine if the battery has been recently disconnected (FSM 13Ad-36). If so, start the engine, let it warm up to normal operating temp, and then let it idle for 10 minutes before shutting it back off. This should clear up the idle inconsistencies if there are no other problems.
3) Regarding the MAF acting like it was disconnected (not the same as malfunctioning), in such an event the vehicle will actually revert to a fail-safe mode. The idle should stop hunting if the sensor is disconnected, running now on predetermined fuel maps. These won't be the most fuel-efficient maps for sure, and will likely be very rich.
View attachment 447759
4) Regarding your battery drawing down to 12.3v after a few days of driving. It seems odd that your battery is only showing 12.3v, even after regular drive cycles (and it being charged twice). A healthy battery should have no trouble holding at 12.7v even after a few days of sitting. Hopefully this is due to your parasitic draw issue and not a charging system or battery problem. Fingers crossed it is in your dome light and not somewhere behind the dash. Start with the simple, pull the bulb the same way you'd pull the fuse and see if the draw goes away. How old is your battery? How clean and tight are the terminal connections? How clean are the engine bay chassis grounds?
...sorry for the over-dump of info. It's probably not as helpful as I think it is.
No way to give too much info!
I just installed a brand new battery and new terminals a few days ago to eliminate that as the cause. As I was charging the old battery it was making a bubbling noise and was told that means it is shot.
Someone else also mentioned it should still run even if the maf is disconnected. But it won’t run for me if its disconnected or when the battery volts get too low. It will rev then almost stall then rev again. If I give it gas it will stall.
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haolepinoy
Incomplete Idiot
I would try the 10 minute idle procedure talked about earlier. Let the system relearn, uninterrupted. Then see if it stops hunting.
If the problem persists, test the MAF and its connector again. Rule out whether or not the problem is there.
Have you found out what that rogue connector goes to in your engine bay (I looked into your build thread)? May be important.
If the problem persists, test the MAF and its connector again. Rule out whether or not the problem is there.
Have you found out what that rogue connector goes to in your engine bay (I looked into your build thread)? May be important.
coffeegoat
Adventurer
When you cleaned your MAF, did you also clean the throttle body? Haolepinoy is right on the money with the idle re-learn process it fixed my low idle but I found part of my issues was I needed to clean the throttle body to clean up its response before it learned the idle quickly. I think it was a couple of days before everything smoothed out. You can clean out the throttle body with whatever your preferred solvent cleaner is, lots of folks around here use seafoam.
I have a feeling that if the throttle body is dirty/sticky, the input/response variables don't sync up well so when the computer tries a set point and the throttle body doesn't actually achieve it and when it doesn't idle correctly it assumes it needs to change more, and it oscillates around until it gets it worked out (eventually) whereas if you had a clean throttle things would resolve more quickly.
I have a feeling that if the throttle body is dirty/sticky, the input/response variables don't sync up well so when the computer tries a set point and the throttle body doesn't actually achieve it and when it doesn't idle correctly it assumes it needs to change more, and it oscillates around until it gets it worked out (eventually) whereas if you had a clean throttle things would resolve more quickly.
I’ll second the importance of cleaning throttle body. I’ve had it be an issue on my Montero but also on another vehicle. I had an idle hunting issue with it and I inspected the throttle body but it didn’t look very bad, I’ve seen much worse. I cleaned it anyway and it solved the problem immediately. I was surprised. I consider it routine annual maintenance.....
jasonsuperb
Observer
Not a lot to update yet. With the new battery it is running fine just still low mpgs. The scanner was draining the battery so I removed that when the car isn’t running. Still not sure what was specifically causing the idle issue and codes.
Another forum member in my build thread found that my truck might have part of the harness from a 2001-2002 montero due to the extra connector and it could be to blame.
It’s currently at Mitsubishi for a tranny flush and timing belt job. Told them about the other issues and hopefully they might be able to shine some light on the subject.
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