Engine Cutting?

[Toecutter]

I know other people have had similar problems, but here is mine.

I flash tuned my car about 2 weeks ago to the 8psi tune, and have been loving it since.

This week though, the car keeps having problems at around 4000rpms

It backfires and sounds exactly like the traction control holding it back, though it isn't traction control.

I cant even give it a good boot now because it chokes at 4000rpms and sounds like sh*t.

I haven't re gapped my plugs yet, going to do that tomorrow and I hope it fixes it but I thought it was odd that it is doing this all of a sudden and not when I first flashed it.

[RHR]

could be springs but id do the plugs and then see how it goes

[XRPete]

yep I agree do the plugs. should help

[Toecutter]

Thanks, ill give an update tomorrow of how it's running. Should be getting Nizpro valve springs next week so hopefully one way or the other it clears up.

[ROLMDL]

sounds like you have the same problem PERVIE had. might be worth

checking out his thread about it and give him a PM as he has solved the problem.

[LUMO]

your plugs either need regapping or you need new ones..

[PURVIE]

It sounds like your hitting boost cut mate, does it make a wierd burring noise at high rpm? What mods have you done? When I replaced the centre muffler with hotdogs and added a CAI I had a similar problem. A custom tune sorted out my problem, so im guessing your tune is generic?

It wouldnt be valve springs, the car wouldn't splutter or make wierd noises they would just float, meaning it wouldnt hold boost. Other factors that can contribute to boost cut (without a custom tune) is an upgrade cooler, guttered cat, spark plugs (misfiring), could be even fuel pump I.e. running lean. I see your from Melb if you wana take me for a drive I might be able to help you, ill be able to tell you straight away if its hitting boost cut or not...

Edited 20/02/08 09:55 AM by PURVIE

[Toecutter]

Thanks for the reply mate, its doing exactly what you described, that weird noise at high RPM's.

I have a standard BA xr6t. with a high flow cat and 8psi tune.

Have injectors, cai and ic in my bedroom waiting to be fitted.

I think it has only really changed once I had the CAT fitted, desperately needing a tune but I'll wait until I have valve springs fitted so I can get headsex to go to work.

[CJ_AK]

This is a long shot, and dont want to sound dumb.

But have you checked out all your plumbing?? The reason I ask is because this was happening to my mates car when he custom tuned it for 12psi.

I had never heard of it happening before, but when boost was peaking, one of the pipes would 'collapse' causing a choke/cut out in the top end.

Just a thought, may not be related to your issue at all.

[Toecutter]

I will check it all out in the light in the morning, thanks for your help.