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Discussion Starter #1
Hello all,

After yesterday's discovery on the dyno, my R32 is running dangerously lean under full load.

Only mods are:

HKS Racing suction kit, Japspeed downpipes, de-cat and exhaust.

I've reset the ecu via battery disconnect and even changed the AFM's for newer one, even the timing has been set to standard.

Any clues as to why it could be running so lean? Fuel pump? Injectors?

Really don't want to have to go aftermarket ecu, piggyback, as this will be the only mods I will do.

Thanks in advance.
 

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ive had this and the voltage regulator that supplies power to the fuel pump was faulty.

hot wired fuel pump to constant full battery voltage problem solved :)
 

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Discussion Starter #4
Anyone? Come on, surely I can't be the only R32 owner that has had this issue?!
 

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you need to check fuel pressure first and see if its dropping.

what dyno did you use ? they should really have had an idea what to check tbh.
 

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Discussion Starter #8
I used Surrey Rolling Road.

Seeing as he isn't a tuner (he said possible fuel pump issue) I thought I'd ask real experts - you guys!

Many thanks, so if I just stick an up-rated pump in will this cure it or will it still have possible voltage issues?
 

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The pump is probably fine, they are designed run a two speeds, only switching to high speed under load. That mechanism can fail and you get stuck on low speed and it runs lean. The switch is on the earth circuit and just bypasses a resistor when high speed is needed, so the quick test/fixis to directly earth the pump to the chassis so you get high speed at all times.
 

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I have heard about the fuel pump earthing and voltage issue before and is likely the problem. A possible mod is to direct wire the pump from the battery to ensure its getting all the voltage it needs.

Earth issues on these cars are only likely to get worse. When I had mine I also ran an earthing kit in the engine bay for added peace of mind.
 

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Discussion Starter #12
So, the common trend is the pump.

Any of you nice chaps got a diagram/pictures of how to do this?

Also, what wire grade for an earth do I need?
 

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A few things you can try :
Change the fuel filter if it hasn't been changed.
It could be a duff chipped ECU (I've had it before) so try a standard ECU on it.
Check the fuel pressure.
Nissan wiring looms don't seem to age very well on the Skylines so its worth cleaning up all the engine loom earths.
Check voltage at the pump as suggested.
Try another fuel pump.
Get the injectors tested/cleaned

Cheers

Stu
 

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i could be your Mafs my gtr was running very lean when i first got it. due to the mafs not reading the airflow correctly. crap just noticed you have already tried changing the mafs
 
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