ive searched for hours and cant find much, so here goes.

its a 92 j spec tt, has boost jets and chip, runs well under normal driving or if i build the revs up to 3-4k and then floor it, but if i floor it from under 3k its holding back alot! both boost gauges stay constant (0.9 bar) plus ive done a leak test, all filters and plugs changed, cleaned elec conectors afew times, decated it and by passed the carbon canister, i cant think of anythin else to try to stop it holding back under full throttle, but even when i let the revs build it still doesnt go as well as it should. any sugestions???

Happened on my skyline turned out to be afm, BUT Same thing happened on me 300 zx 92 j spec boost jets etc And it was a faulty coil. If your in my area come over as i have spare we could try. Muffin.

You'd need 6 spare coils then Lol? Very doubtful one coil would cause this on its own??

You'd need 6 spare coils then Lol? Very doubtful one coil would cause this on its own??

 

 

Actually, I wouldn't rule that out entirely. If one coil is starting to break down then that symptom will most likely show under max load, so foot flat down at max rev's it's a possiblity.

already ruled that one out, with 6 good ones i have

already ruled that one out, with 6 good ones i have

Oh well you know it's not that then!? What's next? Did you try another AFM?

but, it had an engine swop at some point for a series 1, and it still has the egr attached the it. i disconected the hoses from it and made them air tight, but could this have somethin to do with it? again this replacement was done by zedworld

 

Not sure its the MAF if you can get the car to rev over 2,500rpm or the EGR, as the EGR works by redirecting some of the exhaust gasses back into the combustion chamber to reduce the combustion temperature to control emissions, and only works when the engine is cruising but is off when on idle and full throttle. If EGR is on when idleing the engine will idle rough or stall. Same as if the EGR is on with hard acceleration, resulting in a lack of power. So without the EGR connected it shouldnt make any difference to accelaration, only when cruising will the engine suffer as it runs lean for economy, and without the EGR you wont get the benifit of it cooling the combustion chamber down so can cause the engine to det.

 

Try cleaning the ECU temp sender, the green shite causes havock with these engines, sending the wrong signal to the ECU, so thinking its cold when it is hot and altering the timing as if the engine was cold.

 

I had this same problem with my car, it would hold back over 3,000rpm turned out to be a cracked injector tip covering half the jet, might be worth considering?

Ok What about the Crank Angle Sensor?? Has this been checked? Could be Failing at high rpm?

If the MAF has failed completely then in theory the car won't rev above 2400rpm, which is the safety get-you-home mode.

 

Doubt whether the CAS could fail in a way which would cause this - it's a simple device with a couple of LEDs and a rotating disc with slots cut in it (much like the old trigger systems on a Piranah ignition system).

i did try one a while ago, and made no difference then, im startin to think it cud be a restriction in sum pipe or even exhaust. does anyone know wot tests can be done on an amf, voltage etc??

If the MAF has failed completely then in theory the car won't rev above 2400rpm, which is the safety get-you-home mode.

 

Doubt whether the CAS could fail in a way which would cause this - it's a simple device with a couple of LEDs and a rotating disc with slots cut in it (much like the old trigger systems on a Piranah ignition system).

Possible his could be ok! Mind you i had one that failed at anything over 1200 rpm and that showed up on the Consult too!

I still have it here somewhere as i stripped it down to see what was inside that could be faulty ;)

i did try one a while ago, and made no difference then, im startin to think it cud be a restriction in sum pipe or even exhaust. does anyone know wot tests can be done on an amf, voltage etc??

Is there no one near you with working parts you can try so you can at least eliminate what is not faulty?

wudt the cas show up on a diagnostic?? not tried the injectors, i'll whip em out over the weekend. the temp sensor connections are cleand regularly! had one go and melted my heads!

i did try one a while ago, and made no difference then, im startin to think it cud be a restriction in sum pipe or even exhaust. does anyone know wot tests can be done on an amf, voltage etc??

 

you would get code 12 come up on an ECU check if you had a fault with the MAF (AFM) Did you read my post above explaining it could be the ECU temp sender? or have you tried cleaning it?

 

EDIT.. beat me to it :rofl:

yeah, read it and re cleaned it!

Again try MAF

CAS would give you code 11, but as AndyP says doubt its the CAS as the usually fail when they get hot and the gap gets larger causing the engine to stop running, and the engine will only start again when it cools down and the air gap gets smaller

When my maf got wet, ohhuur!

 

my car would rev to about 3.5k rpm then totally loose all power, it would go above that but it juddered badly. JWT ecu and JD chip, so maybe would be different on a stock car.

 

Swap tested the maf with one from an NA and it completly sorted it

Rite, sorted!!! turned out to be the springs in my bailey dump valves! the 5psi i used to presure test for leaks wasnt enough for them to leak, but driving at full throttle was! did have another problem a few days later, car was a biatch to start when cold, as if it was only runing 4 cylinders, then seemed to be running hot, although the gauge stayed where it should, turned out to be the temp sender to ecu!