Backfires Help

[aridyne]

I have an issue with my R33 S1, I am running a Highflowed turbo with FMIC and standalone Haltech ECU, I have done some other minor mods like custom cold air and 740cc NISMO injectors yet I keep finding that on the dyno at 14psi I am backfiring around the 4000-5000rpm range? now this happening in any gear and well the system is showing that the engine is getting enough fuel and air. Does anyone know what else it could be? could the valve springs be a bit soft?

I want to run up to 18psi yet I am unable to with the current predicament?

HELP!

Aridyne

[BigDatto]

tried shortening the plug gaps ? 4-5k RPM is about where they usually blow out unless gapped down.

[aridyne]

tried shortening the plug gaps ? 4-5k RPM is about where they usually blow out unless gapped down.

I'll give that a go. I am heading down to see my baby today so I should have a looksie at these and work it out.. could it be anything else? As it does idle a little rough and doesnt normally start first up in the morn and needs some tlc to get going

[HIPSI]

tried shortening the plug gaps ? 4-5k RPM is about where they usually blow out unless gapped down.

Yeah same thing happened on my mates gtst. Try gapping down your plugs i think it is around 0.6 or 0.7.

[aridyne]

Well we've tried that and still its happening, so we are going to use a 3bar Map sensor for the Haltech and see if that helps as the haltech 3 bar map sensor is actually meant to be used when going over 15psi.

I am still at a loss as what it could be.. I am going to downsize the injectors to help with the idle to 550cc Sards.

Will sell the 740cc's ones.. as I have only had them in the car for 1 month and well they are just to big for my applications at the moment..

[LANFOH]

Have you still got the standard coilpacks in? This might be the problem, they might be on their way out??

[aridyne]

They are new coils, we tried that already

this is what is stumping us.. new coils and modules, new injectors, reg and pump, new high flowed turbo and so on..

[LANFOH]

I read in a previous thread somewhere, it may have to do with your crank angle sensor but I read it while ago and I might be completely wrong, but another avenue that you can explore/check.

[aridyne]

I read in a previous thread somewhere, it may have to do with your crank angle sensor but I read it while ago and I might be completely wrong, but another avenue that you can explore/check.

Well that could be a option, I will have to check and see.. I thought it might be the valve springs myself at one stage but who knows.. its a tricky subject for me.