Andy Gough

Thanks greasemonkey for your reply.

I don't think its 'knock' either cos it would do it more when hot rather than be evident mostly when the engine is coolish.
I phoned my dealer, and the earliest they could fit me in was in 10 days time.
It has to go in again anyway to cure the knock from the transmission area that appeared after swapping the clutch( which they have tried to fix before) and the other knocking from both rear struts which they have also tried to fix before which I have has from new.

It's getting a bit beyond a joke. £25,000 for a car that depreciates at nearly £50 a day, comes out of the workshop worse than it went an and knocks like a 1972 Marina.
At least they give me a bloody Micra as a loan car!

[Edited by Andy Gough - 11/4/2003 5:24:04 PM]

Andy Gough

My sti 8 has developed a weird noise. I can potter around in the car and let it warm up, but for the first 2 or 3 times after that when I accelerate, I get a strange tinny rattling noise from the drivers side of the engine. It's always between 4000 -4500 rpm and is rev related. After two or three times of going thru' that rev range it stops and doesn't repeat until the engine has either been left standing for a few minutes or i've been driving like a wuss in traffic for a few miles. It's very hard to pinpoint, but sounds turbo related, as it is just at the same time as the turbo kicks in. On the other hand, it might be piston slap accentuated by the turbo giving the engine some work to do.

I'm not impressed, I haved to say.

Any ideas folks?

[Edited by Andy Gough - 11/4/2003 5:23:20 PM]

philgr

Are you sure a heat shield has not come loose, these tend to rattle at a given RPM and are sometimes heat releated, there are planty of heat sheilds around the turbo / exhaust area

Phil G
STI8 PPP

greasemonkey

Piston slap is about the least likely of all the possible explanations at this stage. Phil's probably on the money with the heatshields, but these can be hard to isolate.

Either way, if you have a warranty, the main dealers are the people who should be spending their time figuring it out.

The Fixer

Piston slap is very unlikely with your car as it has tighter piston to bore clearances than "classics". Get it into the main dealer asap. I have just had a major problem with standard fuel rails, 1/2 bar difference on fuel pressure between 1 pair of cylinders and the other. i.e. the pair supplied by the back of the fuel rail were running lean!

Bob Rawle

Does it sound like pins in a tin can ?

bob

Andy Gough

Pins in a tin can would be a good description actually.

Andy Gough

Any ideas anyone, in particular Bob?

greasemonkey

The "pins in a tin can" sound is what knock commonly gets described like. However, before you get too alarmed it's still likely to be something else.

The problem with describing any such noise is that there are plenty of potential causes and we're really not in any position to diagnose without actually being able to get our heads under the bonnet.

If this is a worst case scenario, and what you're hearing is knock, something's gone seriously awry to cause it. Either way, you want to get it down to a main dealer/specialist for some proper diagnosis ASAP.

Bob Rawle

Reason for the "pins" question is that quite often an engine will "spit" at you when barely warmed up, the ecu "should" react to knock BUT might not if your boost level takes the engine outside its knock learning/ign learning load range, therefore it "could" be det.

Suggest finding someone who has Deltadash and det cans pdq as dealer may not have enough knowledge to check/realise this.

Is the noise a constant or fragmented? Do you know what the boost is doing and what level it's reaching ? 4-4.5k is the rev range when high engine load would be reached if accellerating from say 3500 rpm for example.

bob

Catalunya 051

The only other possible cause depends on whether there is an injector solenoid fixed to the drivers side suspension strut mounting on your car (there is one on the classics) this clicks quite loadly and you can hear it in the cabin. Does your noise happen when stationary in neutral and you apply throttle?

Andy Gough

If i drive gently through that rev range, there is no noise. If i drive thru' at medium or hard throttle it is there. If I left foot brake and hold the engine under load at 4,000 rpm it is constant.

But once it has occurred 2 or 3 times and presumably the turbo has warmed up, the rattle stops until the engine/turbo/my rag(!) has cooled down a bit when I can replicate the symptoms again.

still, it's a bit difficult to hear sometimes, what with the rear struts banging away and the bloody gearbox wandering around the transmission tunnel! LOL (Not)

dhorwich

Try starting the car getting it to the temp it normally occurs at, then open the bonnet, find the accelerator on the throttle body and rev the engine up slowly to the 4000-4500rpm and try and listen from where the noise may be coming from. If it still makes the noise then i would say its prob heat shield e.t.c and not det as i dont think you would get audiable det without load i.e in neutral.

Dan

Andy Gough

I don't get the noise at all if i drive gently thru the rev range on light throttle opening. It sounds too 'hard' to be a tinny heatshield though.

nom

I'd very much follow Bob's advice here - 4-4k5 is the 'peak efficiency' point & very prone to knocking, & all the conditions that you can make the noise occur at are exactly the conditions that would promote knock.]
Failing getting your hands on DeltaDash, I'd try adding a bottle of NF (or other high-quality octane booster), then have another go at 'making the noise'. If it has gone away, or is much harder to promote, it's very likely to have been det... if it's still there, it the heatshield or something like that Not exactly a technical test, but should be a good guide...

Andy Gough

Sounds like a good idea Nom. Thanks.

Bob Rawle

From curiosity what fuel grade do you use and from what source (ie brand)?

bob

Andy Gough

I had my ECU reset at 1st service and have ALWAYS used Optimax.
Since the onset of this problem I have used Optimax from 3 different sauces.

Bob Rawle

Why a reset, there is certainly no need to do that, re the fuel it just reinforces the "get it checked with DD" comment. Noms idea is a good one, put booster in with your next fill up (say 2 rons worth) and see if that stops it. I bottle Millers is about that or 100 mls of NF.

bob

Andy Gough

I had the ECU reset at the first service as the dealer had put ordinary unleaded in. I understood the ecu needed to reset to take advantage of Optimax and as it cost nothing to have done thought I might as well.

Bob Rawle

Ecu is always adjusting itself real time and would very quickly have sorted itself out, given that it takes three tanks of fuel to flush a change over out then resetting is not the best thing to do as the 95 ron would still be lingering. However it would have adjusted if it saw an issue.

cheers

bob