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same problem

cav

By cav,
in Engines & Forced Induction

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cav Enthusiast

cav

Posted
Posted

still have a miss in my r33 under load at 5000rpm at 10psi.

have changed the spark plugs.

had it on the dyno with a fuel pressure guage( pressure good flow low)

replaced the fuel pump(nippon denso high pressure 400hp pump)

im going to clean the coil contacts where they go onto the spark plugs and ill check the little springs in the end of the coils.

want to know if anyones heard of boost cuts being as low as 10psi?

or maybe a boost sensor on the motor thinking it is over boosting?

the knock sensor might be sensing pinging at this certain rev? (havent heard any pinging)

any ideas let me know.

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rs73 Grand Master

rs73

Posted
Posted

when u changed ur plugs did u set a correct gap? .8mm is the general consensus here. what plug heat range did u use?

also do you have aftermarket ecu? stock ecu will sense boost increase and kicks in boost cut, can be as low as 10psi especially on cold nights. pfc will definitely fix that, otherwise a cheaper safc can do the job well if tuned properly.

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rs73 Grand Master

rs73

Posted
Posted

hm.. hard to tell. cutting boost wire may not bring u anywhere as the ecu will need afm input, otherwise it'll go to limp-home mode and stutters at 2000rpm (found out abt this when my one of my afm wire was accidentally snagged).

i think could be something else causing it to miss. hopefully not a serious issue. can be quite a bitch to track down. i had similar issue in my car for over a year when it turned out to be fuel pump dying. had it replaced and all is sweet.

oh i just remember, what boost controller u use to run 10psi? dun trust any simple cheap bleed valve, it may spike, especially on higher gear. ask ur tuner to check it on dyno. best boost controller are always the electronic ones.

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