*2 problems* redtop #63 ecu MAF sensor ground burnt

[mysharonna]

I am helping a friend fix his s14 hatch. We have been fixing a few problems from a previous owner and I have ran into a problem I haven't seen before. I have tried searching BTW.

This car has ran fine for the last 1500 miles, just a little rich. (sticking injector)

Problem #1

Pin #17 (MAF sensor ground) is burnt and missing.

http://img855.imageshack.us/img855/9495/img000092011061914311.jpg

Anyone have any idea on how to fix this?

The ecu looks fine other than that. I have seen where there are other spots that can burn, but this is a new one. I can only assume that +12v was hooked up there, but checking the wiring, everything checks out. I grounded the maf ground to chassis and it seems to work.... but see problem #2


Problem #2

Cylinder #1 isn't firing. I have checked coil packs, injectors, all wiring from end to end, compression etc. We can't seem to figure it out. It runs no different when lifting off cylinder #1's coil, or pulling the injector clip.

I am going to try my ignitor tomorrow... even though #1 is getting spark.
This isn't a MAF problem btw.

[mysharonna]

So I fixed problem #2..... It was yet another bad injector.. damn sr's!

Still waiting on someone to chime in on problem #1.

[cotbu]

I thought you fixed it, so i didn't post this yesterday
clean the working area. check the continuity on the remaining trace to rule out a burnt trace. then get an old ecu remove same size pin or get a cotter pin or even paper clip solder it in. I've repaired many of ecu's like yours. It's not too serious

p.s. you can hammer the plug end of the paper clip to widen it.
you can even run a wire straight to that point then make the wire extend out of the ecu plug but it's no longer plug and play.

[mysharonna]

Thanks for the info. I was going to use an old ecu to steal a pin out of... just have to find it lol.

Just to update, I grounded the MAF sensor ground wire to the chassis and the car seems to run fine. I have read about regounding the MAF, but I just want to know what the ecu does with the MAF ground.

[codyace]

The Maf grounds on older Nissans typically fail or are weak. There isn'y anythign wrong with grounding the plug to the chassis and call it a day. (B chassis guys know this all to well)

WIth that said though I'm unsure on what grounds may also be connected to that ECU pin. If it's really only the maf ground, then I'd ignore it for now and see if anything becomes an issue. If it's the shielded wire ground there are quite a few and should be repaired for sure.

[mysharonna]

It is the shielded wire ground. There aren't any other grounds using this wire. The MAF signal pin is fine, as is the power (of coarse), its just the ground wire.

I ended up leaving the ground wire as is and splicing in a ground to chassis. It seems to work fine this way until I can solder in a new pin. Ill update when I do that.

[codyace]

It is the shielded wire ground. There aren't any other grounds using this wire. The MAF signal pin is fine, as is the power (of coarse), its just the ground wire.

I ended up leaving the ground wire as is and splicing in a ground to chassis. It seems to work fine this way until I can solder in a new pin. Ill update when I do that.

The shielded ground for the maf is also connected with the CAS and CTS and some other similar circuits. With that said I also recall their being multiple grounds on the ECU for that circuit, but it's been a while since searching it.

Yup that spliced ground on the MAF will be totally fine :D IIRC the new wiring specialities harness are set up that way now too.

[mysharonna]

Cool thanks for the input! I searched a ton and found some threads on other sites about re-grounding the MAF so I went that direction. I mean if you think about it, it makes sense.