vacuum leak? timing issue?


Asked by Apr 15, 2012 at 08:35 PM about the 1991 Nissan 240SX 2 Dr SE Hatchback

Question type: Maintenance & Repair

so im pretty sure its a vacuum leak somewhere or timing somehow fucked up for no reason, cause my 240 idles when the maf is
unplugged but when i plug the maf in it freaks out drops its idles till it dies and when you put the pedal to the floor (maf plugged in
or not) it acts like it has shitty launch control and has the rpms go to 3gs and drop to 1500 then back and fourth... need to figure
this shit out.. it still shoots flames btw to anyone who cares but yeh if anyone has any ideas that would be fab

5 Answers


Check the maf voltage, and ground your ECU and maf to the frame. make sure to get all the ground wires on the ecu togeather and then run one 10-8 gauge wire from them to the frame/body. The maf unpluged will go into safe mode 2400rpm limter but it will get you home I guess is what they thought. What engine do you run and any mods or work done to it?

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Best Answer

i have a ka24de header exhaust intake and egr delete. I thought that maybe the limp mode could be from just really dirty maf. could hotter then normal air do it too cause i have a shortened line cause i cut the other one up that was on it before stupid me. thanks for the help dude


is your intake air temp hooked up?

1 out of 1 people think this is helpful.

Did you try what I said? If it is just the MAF you can unplug it and see if the engine runs any better or worse. (it will have 100% the 2400rpm limiter when its unpluged or the wire are crossed somewhere)

I am having the same issue. I cleaned out my MAF sensor and it didn't help at all. I thought it was the MAF sensor but it must be something else. I bought the car no running had to replace the fuel pump then it would run but was having an issue with the engine not wanting to shut off when I pulled the key out of the ignition... I replaced the ECU and that fixed it and now I have this problem. Were you able to figure it out?

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