R32 running lean ???replaced fuel pump still running lean

[turbohectics]

Fellow Skyline owners,

The car in question is a r32 GTS-T.Car is misfiring above 4000rpm.Changed cracked coils still doing it .

So paid $80 for dyno run....

OUTCOME!!Running dangerously lean when on boost 11psi 4000rpm which is causing the feel of misfiring.

connected pressure gauge up to to fuel line still on dyno ,sure enough fuel pressure drops at 4000rpm when the car runs lean!!

Okay drive with no boost till the walbro 500hp fuel pump comes in !

Mission accomplished fuel pump put in (2 days waiting)........But wait still missing !!

What do i check next .......Dyno guy closed till Monday

I'm thinking fuel lines under the car ??Testing to see if pump recieving 12V Note:fuel filter and fuel hoses in engine bay replaced last week!

Anything else i should inspect?????

Thanx in advance

[CerealKiller]

reset your ECU. It could be in the tuning.

[RB30-POWER]

Fuel pressure regulator is ok?

[RB30-POWER]

Also had another thought, i forgot to post earlier.

Is the pump getting full battery voltage under load.

Could be a faulty FPCM. (Fuel pump control module)

The ECU gets the FPCM to drop voltage to the pump under idle for quiter operation, maybe it isn't switching off idle to the higher voltage.

Check the voltage at the pump.

Also does the aftermarket pump require bigger guage cable for the higher current that most larger than stock pumps can draw?

Give some more details of your setup and testing results, im sure someone can help.

[turbohectics]

Could be a faulty FPCM. (Fuel pump control module)

The ECU gets the FPCM to drop voltage to the pump under idle for quiter operation, maybe it isn't switching off idle to the higher voltage.

.

Maybe .......where is the FPCM located?

I will organise a volt meter to check it out ...though it will fluctuate any way wouldn't it.

Done some research some ppl wire their pump so its on max all the time ,means wear out quicker but there is always plenty of fuel,the unused fuel just goes back to the tank.

How would i know if my fuel reg is dead?

[Trust33]

Ask your tuner.Or if you dont have 1 ask a tuner.

[TommO]

What about your injectors? Tried changing your fuel filter?

What are your AFRs running at above 4000rpm.. ie how lean?

[turbohectics]

What about your injectors?  Tried changing your fuel filter?

What are your AFRs running at above 4000rpm.. ie how lean?

Fuel Filter changed aweek ago! the pressure gauge was connected just b4 the fuel reg.so don't think anything to do with injectors.

Not sure but the line on the dyno graph for afr shot up when the car was missing ,leaning out!my tuner said it's leaning out pretty bad!!!

gonna hassle him tomorrow to work out the prob after all he wasted my $250 on a fuel pump :wassup:

[turbohectics]

Hey dudes problem solved,

replaced fuel pump reset ecu car is running sweet just misfiring now and running rich now ,Put on dyno again

Put my tuners coil loom and coils in and the car ran fine didn't miss a heart beat.

So i am chasing the coil loom $45 from jap wrecker and gonna splurge on the splitfire coils for just under $600(import places want $75to $100 each.Iscored 6 for $50 off a mate but for standard ones which will keep playin up and can't run more than 0.8m gap on the plugs

Now running rich so gonna check out o2 sensor and save for apexi fc!

Thanks fellas