Hi , i'm new here so be gentle......just bought a 1996 wrx import
50,000k , standard , specialist dealer supplied, no probs when i test drove the car but since filling up with 97 ron from my local asda the engine knocks on start up , the knock disappears after 2-3 minuets of idle or gentle running i was wondering if the asda petrol was the possible cause ? anyone got any thoughts?
thanks , pop

I think that could be part of your problems, i dont trust supermarket fuel in any performance car, stick to somthing like Optimax or SUL from BP and possibly and bit of octane booster!

ok Ian thanks i'll give it a try

Is there any hard evidence that supermarket fuel is any different to any other ? If so that would be a scandal to be exposed rather than meekly accepted. Since ASDA does not make petrol any more than it makes 'own brand' baked beans, I've always understood they simply buy wholesale from BP and the rest.

Supermarket is no different from other petrol. Do you really think that Sainsburys, Asda, Tescos etc have their own refineries etc.? No of course not they buy their petrol from Esso, Shell, BP etc.

Honest John in the Telegraph motoring section always recommends that people having engine problems should stop using supermarket petrol in the first instance. Something to do with the levels of additives such as detergents I think.....

Yes but is he simply recycling old myths ? I seem to remember 'Honest John' has been caught out before... Hard evidence anyone ?

Knocks when on tick over or on throttle.

If it does this on tickover its probably oil related.

Some oils make the car sound noisy untill upto temp, Castrol RS 10 60 makes it rattle abit goes after about 5 mins when warm.

Regards
Nic

I own a MY98 UK Turbo. I was worried about the whole piston slap thing. But I think you're right about the oil...purr's like a kitten when up to op. temp.

pop

indeed supermarket fuel is the same as shell/bp/esso etc its just the additives that are put into thel fuel when the petrol tanker gets filled up which is the differance,although optimax isnt a super unleaded fuel with add in's,its refined specificly to be optimax hence why some parts of the uk dont have it yet,due to piping/shipping/transpotation problems.

mike

Ok thanks one and all, tried the shell super unleaded ( can't get optimax) and it's a lot quieter......i can hear the tappets properly now!!!!!

Hi

I you feel it was the fuel then do an ECU reset, there is loads of info in the SIDC FAQ section here Also if you don't know what oil is in the engine then get it replaced with a good quality one ASAP, 15w50 is a good choice for the current UK weather :)

Justin

Isnt there a problem with early Impreza;s that they all have the piston-knock syndrome for around 2-3 mins on cold start-up. I think this mya be the case.

Have a look on a few car guides web-sites. If there is any relavance, I have a 1996 impreza on 50k and I do occasionally on cold mornigs get the piston knocking. After the engine is warm there is no problem.

Quote from honestjohn.co.uk on the UK Impreza 1993 - 2000

What's Good
Came top of Top Gear/J.D. Power 'N' and 'P' reg Customer Satisfaction surveys, and 2nd to Legacy in 'R' reg survey. Excellent reports from owners. Engines are 88 bhp 16v 1.6 flat four, 101 bhp 1.8 litre 16v flat four and 113 bhp 2.0 litre. Auto optional on 1.8 and 2.0. 2.0 obviously the best engine, but 1.6 much cheaper. Recommended.

What's Bad
There was a 1.6 litre two-wheel-drive version from 1994-96. Change of piston skirt design in 1997 led to knocking noise on start up - usually cured under warranty by replacing just one piston. Clutch wear is common because drivers do not adjust their driving technique to the requirements of a four wheel drive car.

What to Watch Out For
Don't bother with two-wheel-drive versions. All Subarus are prone to scoring of the rear discs. Try and feel them through the wheel when cold. Check underside with torch for rocky lane accidents. Check for uneven tyre wear. Make sure clutch not slipping

Hope this helps

James :D

[Edited by Subaru_Impreza_UK - 3/4/2002 12:46:00 PM]