I noticed a week ago, they my car is struggling at top end.

 

I floored it in 3rd and the revs struggled to get over 5000rpm. At the rate it was going up, I think it would have ran out of power before 6000rpm.

 

Any ideas what it could be?

 

 

Stuart

with my massive lack of knowledge of these cars, it sounds to me like maybe a restriction of some kind. Maybe a lack of fuel, ie blocked filter, maybe blocked air filter, maybe even, although unlikeley blocked exhaust? youre cat/baffles havent collapsed have they?

I have had it decatted.

 

I actually think it is since I have had the proper exhaust Gaskets put on. Since then my car is silent. Its very smooth up to 3000 rpm then you notice it struggling.

 

I was thinking air flow too.

 

It could be injectors but I would have thought that woudl cause detonation.

 

Stuart

Hmmm, you need to check air, spark and fuel.

 

Any restriction the breathing? intake a bit clogged? air filter choked? Intercooler not operating properly?

 

Ignition timing out?

 

Det sensor doesn't function above 3,500 rpm.

 

Now check fuel supply.

Some one on 300zxclub said that cylinder 6 could not be working as cylinder 6 is only used when you floor it?

 

Am I missing something or he is talking rubbish?

 

Stuart

Some one on 300zxclub said that cylinder 6 could not be working as cylinder 6 is only used when you floor it?

 

*****X!!:D :D :D

 

LOL.

 

Have you got a fuel pressure guage?

 

Paul.

Originally posted by SRRAE

Some one on 300zxclub said that cylinder 6 could not be working as cylinder 6 is only used when you floor it?

 

Am I missing something or he is talking rubbish?

 

Stuart

 

OMG that has to be.... deep breath.... [just image the biggest pile of severed testicals here] - you get the idea.

 

Bwhahahaha - how obsurd :D

Sounds like AFM :confused:

Originally posted by smw1

Sounds like AFM :confused:

 

 

That was my thought.

What's it like at high rpm without the throttle floored? If you accelerate gently is it smooth?

I think it is the same. I have noticed it a few times even if I put my foot down a long way but not all the way I still feel sluggish.

 

I am thinking AMF like Stuart said but I am also thinking turbo leak as I can hear them an awful lot.

 

 

Stuart

Mine wasn't pulling at the top end of the revs and it turned out to be a plug(s) going down under load.

But on my short list was AFM, fuel pump, fuel pump control unit, bad connection on injector and/or coilpack.

Ive had exactly the same problem for ages now and have tried everything but replacing engine/turbos. Here's a post of mine a while ago giving a few ideas:- http://www.300zx.co.uk/forums/showthread.php?s=&threadid=18979

 

I would say top of list would have to be:-

Boost leak

Fuel pressure

Timing belt slipped a tooth on one of the sprockets.

The reason I ask is that I replaced my AFM recently. Don't forget, the AFM is independent of engine RPM, just the quantity of air flowing through it. So a medium throttle pressure at high RPM should have a similar air flow to a heavy throttle at low RPM.

 

Ignition problems that manifest themselves in this way also tend to ease with a lighter throttle. Now I'm not 100% sure about the following but AFAIK... It's not so much the distance the spark has to travel but what it has to travel through. A large amount of compressed air is more difficult to traverse.

 

When I've had this problem in the past, it's turned out to be a boost leak. With the engine wanting large volumes of air at high RPM, it exagerates leaks under full throttle and also leaks under closed throttle. You get an awful mixture with each. If you balance the boost at the middle of the guage, the boost leak effects should go away if this is the cause.

 

All IMHO as always but I hope something may help.