R32 Rb26 Misfire

[Deez and Teez]

Hello everybody!

I need a bit of help. I am helping a buddy out with a misfire on his 90 GTR and I hit a wall. He was getting a pretty bad misfire around 3K rpm. All of his spark plugs and coil packs are fine. I swapped his coil loom with mine and that did nothing. I did find one bad injector and changed that out. That did help but it is still misfiring. I also used my igniter chip and AFM's on his car and nothing changed. The next item I am going to check is the CAS. We also checked for air leaks but it is boosting fine. Any suggestions?

[GH05T]

how do you know his coilpacks are fine?

fuel pump?

[Deez and Teez]

I inspected all of the windows on the packs and they are all intact. Just to make sure, I put all of my packs in. I did think about the fuel filter too but it seems to constantly misfire hard right at 3K.

[GH05T]

i had a high rpm fault which was dropping rail pressure from a dodgey bosch pump.
otherwise i have spare rb26 coilpacks which might be useful to che......... just saw your location...

[Deez and Teez]

:DHAHAHA!!! Yeah, parts aren't too hard to find here! Are there any ways to check if the pump is failing?

[GH05T]

they get noisy, well the bosch does anyway. not sure how you check it but yeah the bosch just starts screaming.

probably easier and more accurate to check the fuel rail pressure but i now i think about it i doubt it would cause issues at 3000 especially if you can boost past it

[Deez and Teez]

Gotcha! My buddy is getting a used CAS soon for $50. Hopefully that will fix it. I will do some research on the fuel pump too. Thanks!