R34 Gtr Misfire

[Maxi_z]

Hi

My R34 GTR had an engine change after a conrod bearing damage, the engine fitted was a standard R34 GTR vspec engine with approximately the same mileage of the car.

The GTR is fitted with some GT-SS turbos, nismo 600cc injectors, nismo fuel pump, nismo fuel regulator, hks exhaust and decat pipe, apexi power fc with commander and boost control kit.

With the new engine fitted, the gtr was tested and driven for one week,

the engine is running fine, oil pressure is good, they just had to adjust the idle that was a little too high, adjust the power fc map, and all the knock, wideband and other measures are ok.

Now after driving the car for one day, after one hour driving on the highway,

it started to do some short misfires, similar to a boost fuel cut, sometimes around 4000rpm and not under full load.

When doing this the engine check light was sometimes coming on for less than one second, without flashing at all.

Anyone has some suggestions on what it could be?

It was also raining, I don't know if this could have caused some water to get in the AFM's with the standard airbox, or if it could be something else, injectors, spark plugs, coil packs or just something wrong in the power fc settings but it shouldn't have driven perfectly for some time.

[666DAN]

Try the diagnostic, details attached.

Most likely error 21

diagnostic.doc

[Maxi_z]

I have a power fc ecu I don't think it would work.

BTW what would be the possible cause of the error 21?

[sewid]

Coil packs !? First thing, check your plugs.

What's the peak knock sensor reading on the FC commander when the check engine light comes on?

[Maxi_z]

The Knock is low around 30

If it was the plugs or the coilpacks would it show an engine light?

[666DAN]

I don't know with a PFC, it does with the stock ECU???