Strange Rpm Spike On Throttle.

[mikymouse]

Hi. I am experiencing a strange spike when I step on the throttle. The revs spike up approximately 500rpm at around the 3000-4000rpm mark, then back down. This has only been a recent thing.

The car in question is a manual R33 RB25DET Skyline.

I don't think it is a boost spike, as the stock boost needle doesn't jump like the tacho needle does, subsequently this also occurs when the boost needle is reading in vacuum.

Any advise is appreciated.

[mad082]

is it just the needle jumping up, or does the engine rev up higher?

[Rolls]

Are you pushing it when it happens? Possibly the clutch slipping. Good way to test it is in top gear at around 60 rev it up and dump it, if it shudders around and really doesnt like it then you are probably fine, if it keeps revving and slipping then its on the way out.

[FATGTS-R]

Are you also noticing it doesnt happen as much when cold but is more frequent after you have been driving a while?

As above my bet is on clutch slip as well.

[mikymouse]

Hmm, yeh I think the clutch might be on its way out.

I had a good drive yesterday, seems to be more pronounced between 2500 rpm 3500rpm. Will have to try what you said Rolls.

It's not just the needle jumping mad082, engine actually revs up higher.

Seems to happen when both cold and hot FATGTS-R.

I also noticed on the freeway yesterday,when I was in 5th gear and gave it a good rev then back off, up to around 5-6k rpm, a smell appeared.

It was hard to explain, similar to burning rubber. Seemed to have been coming from bottom of the car, definately not engine bay.

Thanks for all your help.

[Rolls]

6k in top gear would be very high load and make the clutch slip if it was worn. The smell is probably the clutch burning. Im 99% sure it is your clutch

[mad082]

smell would've been burnt clutch.

would be advisable to take it easy and get the clutch fixed as soon as possible, as it may not be that the clutch is worn out, there may be something broken.

i had a clutch plate break around where it goes onto the drive shaft. the mechanic said i was lucky to make it to the workshop. yours could just be that the pressure plate is stuffed, but either way its something in the clutch.

Edited July 24, 2006 by mad082