Need help with wierd MAF issue
#1
Mauja He Mauja
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Need help with wierd MAF issue
I replaced the MAF for the 3rd time about 8K ago. She has almost 130K on her. 3 days back the SES came on. Limp mode kicked-in. Next day took her for a ride. SES was still on, but limp mode was gone. Took her to autozone and got the dreaded p100 code. Had an extra maf laying around and switched it. Cleared the SES, car drove fine for 30 minutes, and limp mode kicked-in again. Left work 10 hours later. SES gone, and she was driving fine. Redlined her twice, and about 30 minutes later SES came back along with limp mode.
Any ideas???
Seems like limp mode and ses come after driving for about 30 minutes. Let her sit for a few minutes and limp mode is gone. But then it comes back..
Any ideas???
Seems like limp mode and ses come after driving for about 30 minutes. Let her sit for a few minutes and limp mode is gone. But then it comes back..
#2
tonight, i think i had the same issue. i dunno what exactly limp mode means, but my car felt like it wasn't drivable! surging/pinging/hesitation put together, but overall it felt like a wheel bearing issue gone bad to it's extent. i put it past 3k and BAM! SES LIGHT BLINKS (it was on prior due to o2 sensor)... i'm thinking WTF... i can barely drive because the car just feels like i'm going over lump after lumps in the road. finally i get a mile from my home and then no more bouncy ride. i'm gonna clean my MAF tomorrow and let you know how that goes.
can we share this thread lol... we are on the same page
can we share this thread lol... we are on the same page
#5
Inspect the wireing going into the MAF- the connector itself. Jiggle the wireing while the car is OUT of limp mode and see what it does. Its a common problem on the G50 series Q45 that the wireing to the MAF crapz out, might be similar to the A33.
#6
Originally Posted by OOmaxSE
i put it past 3k and BAM! SES LIGHT BLINKS (it was on prior due to o2 sensor)... i'm thinking WTF... i can barely drive because the car just feels like i'm going over lump after lumps in the road. finally i get a mile from my home and then no more bouncy ride. i'm gonna clean my MAF tomorrow and let you know how that goes.
#7
Originally Posted by Stardust
That's a coil issue not the MAF.
#8
Mauja He Mauja
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Originally Posted by BlackBIRDVQ
Inspect the wireing going into the MAF- the connector itself. Jiggle the wireing while the car is OUT of limp mode and see what it does. Its a common problem on the G50 series Q45 that the wireing to the MAF crapz out, might be similar to the A33.
I was actually thinking that there is a vacum leak?? I will check the wires tomorrow..
#11
Vacuum leak isn't going to set off a MAF circuit code. That code only comes up when the MAF or the wireing to it is bad. You could test the wires by ohming out the connector at the MAF and the ECU to see if there is too much resistance in the wires- too much means its eighter deterriorated wireing or broken wire somewhere.
Per FSM, pinch the PCV hose and see if the RPMs climb up or stay even, if they climb up then you have a vacuum leak- which will not be an issue with your problem.
Check the wireing, and MAF connector for corrossion, possibly spray the connector down with some electronic parts cleaner, and then put in some dielectric grease in the connector to seal it from any type of corrosion forming on the contact points inside the MAF connector and the MAF itself.
Per FSM, pinch the PCV hose and see if the RPMs climb up or stay even, if they climb up then you have a vacuum leak- which will not be an issue with your problem.
Check the wireing, and MAF connector for corrossion, possibly spray the connector down with some electronic parts cleaner, and then put in some dielectric grease in the connector to seal it from any type of corrosion forming on the contact points inside the MAF connector and the MAF itself.
#12
Originally Posted by BlackBIRDVQ
Vacuum leak isn't going to set off a MAF circuit code.
CONSULT-II Reference Value in Data Monitor Mode
Specification data are reference values.
On Board Diagnosis Logic
Malfunction is detected when (Malfunction A) an excessively high voltage from the sensor is sent to ECM when engine is not running, (Malfunction B) an excessively low voltage from the sensor is sent to ECM when engine is running, (Malfunction C) a high voltage from the sensor is sent to ECM under light load driving condition, (Malfunction D) a low voltage from the sensor is sent to ECM under heavy load driving condition, (Malfunction E) a voltage from the sensor is constantly approx. 1.0 V when engine is running.
FAIL-SAFE MODE
When the malfunction B is detected, the ECM enters fail-safe mode and the MIL lights up.
Detected items Engine operating condition in fail-safe mode
Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
Possible Cause
MALFUNCTION A OR C
Harness or connectors (The sensor circuit is open or shorted. )
Mass air flow sensor
MALFUNCTION B, D OR E
Harness or connectors (The sensor circuit is open or shorted. )
Intake air leaks
Mass air flow sensor
Specification data are reference values.
On Board Diagnosis Logic
Malfunction is detected when (Malfunction A) an excessively high voltage from the sensor is sent to ECM when engine is not running, (Malfunction B) an excessively low voltage from the sensor is sent to ECM when engine is running, (Malfunction C) a high voltage from the sensor is sent to ECM under light load driving condition, (Malfunction D) a low voltage from the sensor is sent to ECM under heavy load driving condition, (Malfunction E) a voltage from the sensor is constantly approx. 1.0 V when engine is running.
FAIL-SAFE MODE
When the malfunction B is detected, the ECM enters fail-safe mode and the MIL lights up.
Detected items Engine operating condition in fail-safe mode
Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
Possible Cause
MALFUNCTION A OR C
Harness or connectors (The sensor circuit is open or shorted. )
Mass air flow sensor
MALFUNCTION B, D OR E
Harness or connectors (The sensor circuit is open or shorted. )
Intake air leaks
Mass air flow sensor
though it would have to be a pretty big leak.
how do you know the used MAF is good? id ck it installed in another maxima and see what you find
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#13
Mauja He Mauja
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thanks for the replies. i have ordered a new maf just to make sure. ses is still on. i have not tested the wires by ohming out the connector to the maf and ecu. frankly i don't know how to do that..we'll see after the new maf..
#16
Originally Posted by BewstAdd1ct
per FSM
though it would have to be a pretty big leak.
how do you know the used MAF is good? id ck it installed in another maxima and see what you find![Smilie](https://maxima.org/forums/images/smilies/smile.gif)
though it would have to be a pretty big leak.
how do you know the used MAF is good? id ck it installed in another maxima and see what you find
![Smilie](https://maxima.org/forums/images/smilies/smile.gif)
Zippn- what did you end up doing ? clean up the MAF connector ?
#17
Mauja He Mauja
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I cleaned the connector like 5 times with the electronic parts cleaner. I am getting ready to go run some errands. I will probably drive like a 100 miles. With that many miles, I am sure I will find out if cleaning the connector fixed the problem. Will post results after the drive..
#18
Originally Posted by BlackBIRDVQ
If you had a large enough vacuum leak it would set off a system to lean code 1st before MAF code. Looking at the consult Alpha would be way off.
not quite... the STFT would run lean first, and then then LTFT. if the LTFT isnt out of threshold it wont throw the fault, but if theres insuficient flow across the sensor, the ECM will call it dead in the water with a p0100, and mixture diagnosis gets thrown out the window at that point, going into FMEM.
meh... either way, its not likely, hed have other symptoms and with the way MAFs go on these cars, i doubt its a vacuum leak, but i wouldnt discount it without taking a good look...
#19
I'm going off Alpha on the Consult, which will tell you alot more than normal STFT and LTFT. Its read in % and gives you a better idea of how the car is runing. I hardly use fuel trims on Nissan or Honda, since on a Honda you can see the actual A/F reading, and how much more or less fuel is dumped into the engine via injector duty cycle. Most newer Japanesse cars have wideband lambda sensors which display true A/F ratio using a manufacturer supplied scan tool. They call nolonger call oxygen sensor an oxygen sensor, but A/F sensor. Its able to fine-tune the engine to specific gasoline used in the engine, diff ambient, engine load and intake air charge better than old school O2 sensors.
P0100 is a MAF circuit maulfunction, which pretty much eliminates everything but the electrical parts of that system. If I where to remove my brake booster hose for long enough of a time, it will register a code for system lean- not a MAF problem, even thou its a HUGE vacuum leak.
Nissan FI is pretty good stuff, its got alot of fail safe modes, and has REALLY good misfire detection built in, and if you got a Consult to access it makes fixing the car virtually all but impossible. Early 1990s cars had more sensor values shown and more adjustments you can do via Consult, or tests- than todays Honda cars.
P0100 is a MAF circuit maulfunction, which pretty much eliminates everything but the electrical parts of that system. If I where to remove my brake booster hose for long enough of a time, it will register a code for system lean- not a MAF problem, even thou its a HUGE vacuum leak.
Nissan FI is pretty good stuff, its got alot of fail safe modes, and has REALLY good misfire detection built in, and if you got a Consult to access it makes fixing the car virtually all but impossible. Early 1990s cars had more sensor values shown and more adjustments you can do via Consult, or tests- than todays Honda cars.
#20
Mauja He Mauja
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I have driven her about 150 miles. No more SES. Installed back the maf I had when the light first came on. Redlined many times. She is back to purring...$7.00 bucks is all it cost. Thanks Mike
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#21
Originally Posted by BlackBIRDVQ
I'm going off Alpha on the Consult, which will tell you alot more than normal STFT and LTFT. Its read in % and gives you a better idea of how the car is runing. I hardly use fuel trims on Nissan or Honda, since on a Honda you can see the actual A/F reading, and how much more or less fuel is dumped into the engine via injector duty cycle. Most newer Japanesse cars have wideband lambda sensors which display true A/F ratio using a manufacturer supplied scan tool. They call nolonger call oxygen sensor an oxygen sensor, but A/F sensor. Its able to fine-tune the engine to specific gasoline used in the engine, diff ambient, engine load and intake air charge better than old school O2 sensors.
P0100 is a MAF circuit maulfunction, which pretty much eliminates everything but the electrical parts of that system. If I where to remove my brake booster hose for long enough of a time, it will register a code for system lean- not a MAF problem, even thou its a HUGE vacuum leak.
![Wink](https://maxima.org/forums/images/smilies/wink.gif)
Nissan FI is pretty good stuff, its got alot of fail safe modes, and has REALLY good misfire detection built in, and if you got a Consult to access it makes fixing the car virtually all but impossible. Early 1990s cars had more sensor values shown and more adjustments you can do via Consult, or tests- than todays Honda cars.
![Smilie](https://maxima.org/forums/images/smilies/smile.gif)
#23
It comes and goes eh ? I have had good luck with the new updated MAFs from Nissan so far (knock on wood been ok for over 40k), so I would possibly rule out a bad MAF. I would check the wireing from the ECU to the MAF. Get a hold of a FSM and look at the circuit diagram for the MAF wireing from the ECU to the sensor. Possibly run a continuity check (ohm out) on the wireing. Check for short to ground also.
#24
Hey fellas i got a 2000 Max with the same problem, this limp mode you call is what i been dealing with for a lil while. had it checked out said it was a coil problem need to replace all six. Even bigger problem is getting fixed so i can get the car inspected and get her back on the road. any info you guys can help me with i'd be grateful
-Po
-Po
#27
Mauja He Mauja
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Originally Posted by BlackBIRDVQ
It comes and goes eh ? I have had good luck with the new updated MAFs from Nissan so far (knock on wood been ok for over 40k), so I would possibly rule out a bad MAF. I would check the wireing from the ECU to the MAF. Get a hold of a FSM and look at the circuit diagram for the MAF wireing from the ECU to the sensor. Possibly run a continuity check (ohm out) on the wireing. Check for short to ground also.
![Confused](https://maxima.org/forums/images/smilies/confused.gif)
#29
well i got the car back yesterday she was running like she used to. drove for about 60 miles then the SES came back on, had her plugged back to the comp. got a 430? which is a cadalic converter issue. sounds a lil off to me car only has 77K she shouldn't have issues like that. if any1 knows anything about a 430 the help would be sweet. thanx
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