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Misfiring At High Rpm

samismyhero

By samismyhero,
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samismyhero Apprentice

samismyhero

Posted
Posted

Hey guys.

I bought the car with this condition and havn't been able to get it fixed yet.

At high RPM, i can hear ALOT of misfiring from the exhaust, and I'm losing a whole lot of power, and it's obviously not good for the car.

I've asked all my friends and they're saying that because my R33 GTS-T didn't come stock with a turbo, when the previous owner threw in a turbo he should have upgraded the fuel pump aswell, I'm still running the stock fuel pump.

So I'm buying a new one in the next few days but they're not 100% sure that it will fix it, any ideas?

Thanks.

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samismyhero Apprentice

samismyhero

Posted
  • Author
Posted

Thanks guys I'm going to check the coilpacks today, but i read a different thread about a guy with stuffed coilpacks to fix his misfiring, and by the sounds of it, he was just getting the odd miss, a single pop. Mine sounds more like a machine gun when i get to about 5500.

lcy Rising Star

lcy

Posted
Posted

was wondering what happens if i have already done all the above and i still have misfiring?

COilpack n AFM changed all service done, spark plugs change 6 sets.... all brand new.... tune check.

mechanics reckon COIL PACK LOOM!!!!

shed some light?

Bennett Mentor

Bennett

Posted
Posted

Coilpack loom? Coilpack loom is just wiring, it will either work or it wont. Are you sure all of your coilpacks are actually firing. When the car is running, unplug each coilpack one by one and if the cars idle drops a bit then that cylinder is firing. It the revs stay exactly the same then somethings wrong and that cylinder isnt firing. Swap that coilpack with another cylinder and if it still doesnt fire in the same one then the coilpacks are fine but something else is still wrong. Just work through everything untill you find the problem. Igniter, Sparkplugs, AAC valve, AFM. Lots of things that it could be.

samismyhero Apprentice

samismyhero

Posted
  • Author
Posted

today i checked all the coilpacks, all were in good condition.

During the test drive right after at around .75bar the car jolts and continues to rev but the boost drop to .25 bar.... (it did NOT do this before)

it did not misfire though which indicated to me that it was the fuel pump to start with as the DE fuel pump can handle .25bar but not .75bar if that makes sense.

  • 2 months later...
WOO32 Apprentice

WOO32

Posted
Posted

hopefully it works but for me it only helped clean up the rev range but still not running 100% change ur cas. i changed: coils,plugs, fuel pump,afm, coilpack loom,ecu, and still nothing, but as i changed each item she started feeling more and more like a real car, then i changed the cas and she was fairly clean through the rev rang but i still have the odd cut out here and there + a wierd slight surge feeling while under boost. Any other ideas??

Messiah Mentor

Messiah

Posted
Posted

ok.... sounds like this is fairly stock. have you wound the boost up at all.

Few things to check...

1. fuel pump, when i bought my gtst it wast almost dead... not enough fuel under high load is bad... theres a test where you disconnect the fuel return pipe (i think) and see if its flowing fuel under load. if it doesnt then the pump might have had it (check this procedure with the others i cant remember it properly/safely)

2. As mentioned above coil packs. Mine looked ok but werent working reliably... bought splitfires and it fixed exactly the same symptoms.

Sheriff Wan Proficient

Sheriff Wan

Posted
Posted

Given your car was an NA it doesnt have alot of things that the turbos came with...

Id be starting with spark plug gaps - try 0.8mm and you should upgrade the fuel pump - consider it cheap insurance.

if that still doesnt work look to the ECU - 33's are notorious for not liking increased boost level when close to stock.

Let us know how you get on with that.

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