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View Full Version : 1991 240sx possibly bad maf ? maybe soemthing else.


SencilloMa70
03-16-2016, 07:38 AM
So heres the story and a video

i literally just registered my car, Drove fine all day till I had to drive to the other side of the.. got on the high way and I'm drive and noticing lost of Power miss fire ETC at full throttle trying to catch up to traffic.. Didn't work.. Got the car to steady speed/rpm at 1/4 maybe even 1/2 throttle would be fine .. Got off the high way trying to drive in traffic the car shut off.. Got it started and running with the MAF unplugged .. So I limped to where I had to go. Had to keep doing the 1/4 or 1/2 throttle shit .. Will keep miss firing and bogging .. Trying to get to my next destination .. Then I left it alone and towed it home with my truck. im really stumped. i checked my check engine light codes.. says its good ..i dont wanna buy parts that i dont need.. most of the stuff was done by previous owner.. in the list of that new parts replacement the MAF is not in there. my buddy is giving me one for free so thats always good. just want to see if anybody else can give me some ideas on what to check out with out spending money on unnecessary stuff. dont have much diagnostic tools but i am going to buy a multi meter tomorrow


https://www.youtube.com/watch?v=fHP5Abe7uJ0

this video is with the MAF unpluged
https://youtu.be/HFUCW5PbbMQ

zenkicpe
03-16-2016, 09:07 AM
Having your buddies MAF around will make it easier to test. Sounds to me like fuel pump is going bad on you, hence no codes. Try the other MAF first, if that doesnt work pull the pump out of the tank and check the sock filter, check pump for proper operation in a bucket, check fuel filter and fuel lines, check fuel pump wiring. Something could have been sucked up into the fuel rail and clogging injectors but doubtful since it runs ok at light throttle.

My vote = fuel pump/wiring

SencilloMa70
03-16-2016, 09:25 AM
Having your buddies MAF around will make it easier to test. Sounds to me like fuel pump is going bad on you, hence no codes. Try the other MAF first, if that doesnt work pull the pump out of the tank and check the sock filter, check pump for proper operation in a bucket, check fuel filter and fuel lines, check fuel pump wiring. Something could have been sucked up into the fuel rail and clogging injectors but doubtful since it runs ok at light throttle.

My vote = fuel pump/wiring

well... the previous owner had the pump to a switch.. i have no idea how to put it back to normal..it was fine for the past few months while sitting (starting it for a while driving it around the block) i will take it out since it has a hole in the truck for access. getting the MAF tomorrow will test that also.

zenkicpe
03-16-2016, 11:35 AM
Annnnnd that makes it even more probable. Get a FSM they are available online, trace out your fuel pump wires from the drivers side kick panel. If you are going to upgrade your pump you should think about upgrading the guage of your wire a bit.

SencilloMa70
03-17-2016, 04:15 PM
Annnnnd that makes it even more probable. Get a FSM they are available online, trace out your fuel pump wires from the drivers side kick panel. If you are going to upgrade your pump you should think about upgrading the guage of your wire a bit.

fuel pump is fine..put a new MAF from a buddy turns on runs for 2 seconds shuts right off. If i disconnect a bunch of hoses from the intake tube it will longer... but shut off after a while

https://www.youtube.com/watch?v=mFMgtUBv8BY