vacuum leak? or bad maf wiring?

[RedSubdivisions]

so my shop manager and I are stumped about my car. I just rebuilt my KA up and down (new rings, seals, HG, the works) and when I put her back together she fires right up! Awesome! But the catch is that the car idles a little off when the MAF is unplugged, but she still seems to keep an idle. However, I plug the MAF in and she stays on, but dies out within seconds. I have blocked off my EGR, made sure there was no vacuum leaks upon assembly of the intake manifold.

Now, I'm thinking it's the MAF wiring issue because of two things:

1) when I boosted my KA (and when it failed miserably, btw), I had a "friend" hack my ECU white wire to be used with the SAFC. well, after returning my car back to stock, he used a crimp to put my MAF wires back together. now because those wires are so temperamental, would that cause my car to stall out when I plug my MAF back in? better yet, would ANY part of the wire exposed make that much of a difference to where my car won't hold an idle? and no, my MAF is not bad. I checked it and it's 100% good to go.

and 2) if it was a vacuum issue, then why is the car still running after I unplugged the MAF? I mean, if it was a vacuum issue, that car would die out with or without the MAF if I'm not mistaken. This is just a guesstimate so I don't expect myself to be even remotely right. lol

any input is appreciated, guys. you've helped me out for the past few years.

[OutToWinPAHC]

The thing I hate about Nissan FSM is the electrical prints can be tricky to read. But I would download the FSM EL section and verify that wiring, then clean up the connection and ditch bad crimps. Then see if it helps.

Have you pulled codes at all?

[RedSubdivisions]

well, the thing is that the MAF white wire coming from the ECU itself was the only one that was cut. my car is at the shop right now, so I can't get to it just yet. as far as pulling codes, I'm gonna try and do that tomorrow (I have a full day to myself for that...such fun. ). if I come across anything, I'll be sure to take care of it then. but until then, I'm almost convinced that my car likes to stay at the shop.

[ZOMG.SR20]

the crimp connec. wreak havoc on ECU signals

[RedSubdivisions]

well, I'm at the shop now and I swapped my ECU as well as my whole harness and the car is still doing the same thing, unfortunately (idles without MAF, but doesn't with it on).

I am completely stumped now. any ideas?

[LoserCard]

Replace MAF? I had the same symptoms on my car, but the only difference was it was my ECU in the MAF circuits. Maybe you have two lemon ECUs. Or maybe something in your wiring is shorting your ECUs.

I would check the continuity of your MAF wiring AND the MAF circuit in the ECU.

[alms24sebring]

hightly doubt 2 bad ecu's. I would replace the wire crimp because it might be shotty and see what happens. I had an old oldsmobile or something that where if you plugged in the MAF, it would idle rough and die. But, with it unplugged, it would run great but still throw the C/E light because its unplugged. I didnt deal with it but it came in for something else (along witha million other things)

Maybe theres a certain vacuum leak in a certain place where it allows too much/not enough air and dies when MAF is plugged. I dont know

[RedSubdivisions]

Well, the good news is that I found the problem! Or at least I think so:

we're doing an SR swap for a kid and I decided to try and swap an SR MAF on there for s***s and giggles and see if it runs.

Well, when I did that, I plugged it in, fired the motor up and she idled. I was nearly stunned at the fact that I had overlooked something so stupid. but I'm gonna order another MAF to see if that's the case. ::crosses fingers:: I sure hope it is!