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Old 04-29-2013, 01:22 AM   #1
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MAF Sensor?

Ok this not a focus but I'm sure the MAF work the same. My moms car is a 96 chevy luminia w/ 3100 v6.

The car runs like shit, I did a full tune up nothing changed, cleaned then changed the egr valve no change.

While I was messing with egr valve I was thinking I know if the MAF sensor is bad or dirty it can also cause the car to run like crap so with the car running I dissconnected the sensor sure enough the car started running amazing right after. Plug it back it starts running like shit again.

So... I have her go buy maf cleaner and a new maf sensor just in case cleaning it don't work. I cleaned it no change, I put the sensor in and guess what still no change..... still runs like shit. But... if I unplug it, it still starts running perfectly fine.

Well she need the car to get back and forth to work in so I like shit ill just have her leave it unpluged until I can figure something else out. Drove it around the block runs perfectly fine so un-pluged it is.

My question what kind of damage will it cause leaving it unpluged, and second what else could be bad, that when disconnecting the maf sensor it would run fine.

I plan on this only being temporary till I can figure out the cause.

Sent from 34.0764 N, 118.4296 W


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Old 04-29-2013, 05:05 AM   #2
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Well after doing some research. I found this ignore the numbers but it gives me the info i'm looking for.

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No. Sorta.

The MAF tells the computer what the air density is. The computer then adjusts the fuel delivery schedule (injector timing) to attain a mixture of 14.7:1 parts of air and fuel. Without the MAF, the car might alternate between rich and lean, which won't hurt anything, but might trip the Check Engine (SERVICE ENGINE SOON) light and give codes of P0170 & P0173, and P1188 & P1189.

The car won't be harmed, but the codes will probably come up. All you need to do is fix/replace the MAF and reset the codes -- ignoring the ones I told you about.
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It runs off only the 02 sensors instead. Just wont control the combustion as effectively.
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technically your car can run without the MAF but instead of relying on the sensor input for the fuel trim (most optimum) it will rely on a set of pre-defined fuel trim. therefore, your car can still run but you are not getting the most performance due to your specific driving conditions.

I hope this helps. good luck


From another forum.

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Umm... no

your car probably ran kinda funny and has been getting less than par gas mileage (suprised you didn't notice this, but the mileage won't be too far off) without the MAF, but it is only one sensor your ECU uses to determine fueling. Your plugs are more than likely fouled, and your cat is probably completely hosed, but as for actual mechanical damage, as long as you have been timely with your oil changes, you should have 0 mechanical issues. In the future, get friendly with a shop/person in your area that doesn't charge to hook up to a scan tool and anytime a code pops up, have it checked out, I drive around with my CEL on all the time, but still have it scanned once a month or so... better safe than sorry. But I wouldn't worry in your position, just order a new set of plugs and cat (or catless pipe and 02 sensor simulator) and enjoy the car.
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Old 04-29-2013, 05:08 AM   #3
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I saw another another forums but I can' find it again. In the thread someone mentions to try and do a hard reset for the ECU by unplugging the battery for 30 mins.

The engine has been running so long bad it may have picked up some bad habits and needs to be reset so it can relearn the how to run properly again.

I'm going to try this tomorrow, any thoughts?
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Old 04-29-2013, 05:25 AM   #4
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I dont need to see your google searches lol. (no offense anyway)

have you actually tried replacing the sensor? there's tons of them in junkyards. It could be completely trashed.

If you have a multimeter you can test it.
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Old 04-29-2013, 05:29 AM   #5
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You always hate when I post up stuff don't you mike?

Yes, I tried cleaning the old one, then I replaced with new one. Still runs like shit unless I unplug it.
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Old 04-29-2013, 05:32 AM   #6
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not at all.
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