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Apparent Fuel Cut Issue

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Ok so a few weeks ago my car started to play up. RB25DET S2, PFC, Bosch 040 fuel pump stock afm..

Every now and then whilst cruising along the car would just seem to lose 100% of its power and start to slow down, as if I had taken my foot completely off the accelerator. When i put my foot down a little it would seem to clear up and go again, but it would happen the whole drive after its done it once. This has gradually gotten worse over the weeks and now any sort of positive air pressure aswell as cruising it does this. When it gets to around 2600-2700rpm the engine seems to shut off, fuel cut (PFC) until the revs drop below and it will go again. I wasn't getting into it doing this but I live on top of a mountain and was trying to baby it home up hill and not hitting 2700rpm or into any sort of boost above 1psi isn't exactly easy up the steep bits with tight turns.

Also the fuel pump is a bosch 040 in tank wired up properly. Sounds normal at 1st.. Not very loud but u can hear it wirring away in the tank, but after I start to drive the pump gets really loud and stays really loud for the drive until I shut it off. This happened again this morning. I had to back the car out of the driveway to let dad out, it started up fine, sounded normal. As soon as I pressed the accelerator and got off the clutch the pump became A LOT louder and continued to sound this way until I turned the car off.

I have a couple of ideas on what it could be but would like to hear your opinions and thoughts.


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  • 2 months later...

Hey guys. This has progressed..

The 040 wasn't doing its job and has been replaced, fixed that particular problem. The fuel pressure reg was fine.

New problem.

Spark issue, cyl 2 not running properly, changed coilpacks between cyl 1 and 2 and the problem changed to cyl 1. Bought Splitfires thinking the coilpacks or at least one them were cactus. Put them in and after no more than 5 mins the coilpack over cyl 2 had melted.

I have searched for over half an hour under maintenance, DIY/facts/tutorials and even used the search function unsuccessfully and didn't find what I need. My mechanic needs a wiring diagram for an RB25DET S2 from an R33. Can anyone link me up with this?

He is suspecting a wiring issue, possible broken wire or earth issue. Causing the coilpack to continually fire and melting it. I do need this fixed rather urgently as I'm without a car and start a new job on Monday. He just needs the wiring diagram.

Thanks in advance, hope someone can help.

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The ignitor is driven by pulsing high I believe, so any sort of short should kill the ignitor not a coil pack.

My car randomly melted a splitfire coil pack on me too, threw in a whole new set. No issues with spark since.

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Are there no links for a wiring diagram? RB25DET S2 from a 33..

hey hey try these sites




not sure if thats what ur after but give it ago. should enter ur car into the show and shine im thinkin about it.


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