My 300 Z is ill. If I build up the revs in 1st, I can redline it no probs but under any boost, it holds back at 6000 rpm plus and never reaches 7000 rpm! The plugs seem fine and I'm sure it's not a weak spark issue. Has anyone else encountered this tw*tty problem? Could it be fuel delivery problems?

 

Cheers

 

Shaunmac.

Hehe welcome to my world. Had this problem forever, but much more severe, will not rev above about 5500rpm in any gear, just loses go!

I've replaced just about everything but engine and injectors.

 

I suspect though for you it will be one of following;

 

Boost leak.

Fuel pressure a bit low, especially once the revs pick up. Could be cause by weak pump, nackered pump controller, clogged filter or fuel pressure regulator. Might be useful:-

http://www.z32.org/html/fuelpumpdiagnostics.shtml

http://www.z32.org/html/fuelpressure.shtml

http://www.z32.org/html/fuelpumpcontrolunit.shtml

 

Timing belt may have slipped a tooth. Bit of a PITA to check, im about to change it again, 2nd time in about 5months.:mad:

Also might want to check ignition timing is ~15 degrees TDC.

 

Clogged cats. Rotten egg smell at all?

 

Perhaps a dodgy mas?

 

Air filter isnt clogged?

 

All coil pack in good nick? One could be breaking down at high revs,- seen it happen b4.

Im sounding like a broken record now ;)

 

Clean your PTU. This is how my car first started to get ill. But at first I would get to 5000rpm and then it was like my car just died.

 

The revs then came lower to about 4000 and then after that around 3000rpm before completely giving up on me :(

 

Stuart

Thanks guyz, your advice was really appreciated. It was the MAS.

 

Cheers

 

Shaunmac.

How did you diagnose, fix this problem?

 

Did you have a spare or something?

My brother drives one too ;)

Ah you jammy git, where are you going to get a permanent replacement from?

 

I just wonder if that could be the cause of my problems. I've done this test ( http://www.z32.org/html/afmdiagnostics.shtml ) but personally think it means bugger all as it doesn't test at wideopen throttle etc.

Anyone got one, or maybe even a conzult if that checks mas readings, i can borrow for beer mooney?

My mechanic has 2 of them - I put them in the for sale section the other day - £125 plus shipping.

 

Vijay

Thanks, but i'm gunna try and source one to borrow first as i don't want to buy it if it's not the problem. I've bought loads of things recently to try and diagnose but nothing made a difference and im left with all this stuff!

After cleaning the AFM & removing a leaf trapped in the gauze, the thing now works!!

 

Robtor, is there no one near you that is willing to help you out? All you need is to swap bits till it works. If you could get down to Bangor N.Wales, I'd help out.

Thanks for the offer but a touch to far for me to go!!

 

There aren't really any Z's round here, and the nearests ones are owned by people i dont know and i don't have the cheek to just phone someone up and ask if i can take random bits off their car!:D

 

I've ordered a mas now, and im pretty sure it won't fix the problem, so that's another 130pounds down the drain. Mine visually looks fine but it's one of the few things i haven't replaced, so i've got to give it a try.

Hey Rob,

 

If it doesn't sort your problem out, I've got someone who'll have it off you, so no money lost ;)

 

Vijay

Ta very much vijay :)

 

As i say, there's nothing i can do but try it.

Just gets annoying at times as i've replaced practically the whole car now!! Only thing left is the engine :)