One for the guru's!

[the_tonkau]

Have had this problem since I got the car and it was stock as a rock and its still the same after all these mod's !!! The engine misses with any more than 12psi boost. This week all the following gear went in-

t3/t4, FMIC,PFC,Adj Fuel Reg,Big Fuel pump,z32 afm,new plugs(copper-correct gap) and we tested every coil pack with a known good item. STILL MISSING. It runs like a dream until we go over 12psi. I have been told it could be the crank angle sensor(dry solder joints??) but we ran out of dyno time and crank angle sensors. I hope I have given enough details for some of the SA GURU's to offer some idea's.

Cheers

Stevo

[Sydneykid]

Hi Stevo, what heat range plugs? Gap?

[jtech]

is the ecu standard? could be fuel cut, or spark plug gaps... i would check that as i had the same problem... regapped it and it was fine....

see how you go.

[the_tonkau]

SK - AHA!! I HOPED YOU WOULD DROP IN, IT'S GOT 7'S WITH .8MM GAP. PREVIOUS TO THESE COPPERS WE TRIED IRIDIUMS ETC AT MANY GAPS AND HEAT RANGES WITH NO LUCK.

JTECH- ITS GOT A POWER FC SO NO BOOST/FUEL CUT ISSUES

I KNOW THIS SYMPTOM HAS BEEN COVERED TO DEATH BUT I THINK MY PARTICULAR PROB COULD BE AN ODD ONE.......MMMMMMMM

[Sydneykid]

Hi Stevo, mmmm 7's at 0.8, that's what we use. Should be OK.

Leak down test?

[walkoau]

i have exactly the same problem over 12psi!!!!!!!! its very annoying so i just wind the boost down for now! and ive also done the whole experimenting with plugs, but nothing helped.

i have found that it happens alot more before full operating temp.

[51jay]

Have you actually set a boost cut level. Mine is set at 1.46bar If i just touch up to it in 1st or 2nd i get a misfire if i hit it hard under full load in 4th i get complete ignition cut until the revs are back down to zero then ig comes back on and i can restart.

[Jay95R33]

Just a stab in the dark, but a mate had the same thing.

He regapped his plugs from 0.8 to 0.74 and it worked a treat - miss fire totally gone..

It's hard to believe that 0.06 mm made that much of a difference, but in his case it made the world of difference !!

Good luck.

J

[the_tonkau]

No leak down test as yet (maybe don't want to know the results!!) but its an original low KLM's motor so you would hope it has some more legs left. Any other different scenarios to try lads, I am open for idea's. The winner gets a slab!

Cheers

Stevo

[Steve]

One from left field, what sort of bov are you running? Have you checked it is holding boost? correctly adjusted?

[DAMQIK GTS-T]

Check the rubber hose between the turbo and air filter isnt sucking closed.

[Steve]

DAMQIK, if it is the rubber hose, all he would be experiencing is a loss of power.

[DAMQIK GTS-T]

Well I wasn't losing power that I new of but on the dyno @ 6000rpm and @ 14psi the hose sucked closed the mixtures went really lean, (map senced ecu) those rubber hoses to the turbo are ONLY good for stock boost.

I'm not saying it's the problem but at least check it.

[AutoTrust]

Stevo is it a series 1, 1.5 or 2? if its a series 1 have you tried another igniter module? Seems like you've replaced all the normal problem parts. This sounds electrical and it"s boost related so try another MAP sensor. Hope your'e monitoring vitals on the dyno like fuel pressure, new parts can be faulty and you need to know that all your bases are covered. Hope this helps Good luck..

[Sydneykid]

Common Stevo, do the leak down test, it will rule out internal problems. Then you can confidently say its external and swap bits over. We find the best way is to get another car same model and swap them, one by one.

[Steve]

Originally posted by DAMQIK GTS-T

Well I wasn't losing power that I new of but on the dyno @ 6000rpm and @ 14psi the hose sucked closed  the mixtures went really lean, (map senced ecu) those rubber hoses to the turbo are ONLY good for stock boost.

I'm not saying it's the problem but at least check it.

Lucky your car was on the dyno when it happened, you dont get too many chances with lean mixtures at load.

[MegaGTS4]

the_tonkau,

Might be weak spark caused by poor ingnition/motor earth or maybe earth leak on one of your coil packs?

or lean mixture (blocked fuel filter) or faulty injector?

It could very well be the CAS.

MEGA

[the_tonkau]

Thanks boys! Leakdown down test next, then igniter module(its a series one). It has a new fuel filter and monitired fuel pressure on dyno OK. No rubber hose left on turbo inlet to crush. Probably look at the injectors next. Hey SK, when you used this fuel setup as an alternative to getting bigger injectors, could you get a nice smoooth idle? Some times (only first tune) it can be OK then it gets a bit grumpy/rough. Dripping/dirty injectors?.........will keep you updated guys.

Thanks for the input,

Stevo

[the_tonkau]

Thanks boys! Leakdown down test next, then igniter module(its a series one). It has a new fuel filter and monitired fuel pressure on dyno OK. No rubber hose left on turbo inlet to crush. Probably look at the injectors next. Hey SK, when you used this fuel setup as an alternative to getting bigger injectors, could you get a nice smoooth idle? Some times (only first tune) it can be OK then it gets a bit grumpy/rough. Dripping/dirty injectors?.........will keep you updated guys.

Thanks for the input,

Stevo

[Sydneykid]

Hi Stevo, what fuel pressure (above boost) are you runing?