My 1998 MY UK standard Turbo is pinking a little under hard acceleration, noticed a slight hesitation accelerating hard in third. A recent rolling road test said it was running rich. Any one any ideas what the problem could be and is it simple to fix ? (I am running it on 95 RON, which shouldnt be a problem for a UK car).

Also, it smells of hot oil at the top right hand corner of the bonnet, does this indicate somethings amiss, or do they all do this when they get old and are driven hard!

 

Run it on 98 or 99 ron as indicated in the mfrs owners manual unless it has been specifically mapped for 95 ron and the problem will go away.

 

That is incorrect information for UK cars of 1998 vintage.

MY98 UK cars are made to run on 95RON (UK and EU cars only, not JDM imports, if in doubt, look at the back cover of the owners manual, it lists 95RON). If it is pinking there is something wrong with the car.

So the root cause needs to be identified, as it will probably will still detonate on 98Ron (or if it disappears it will probably still have inaudible det, which you won't hear but will kill the engine over a prolonged period).

Possibly a MAF sensor issue, or it has been modified and remapped for higher octane fuel.

Until the problem is fixed run octane booster, SUL fuel, and DO NOT drive the car hard or use high revs or full boost. As doing so over a prolonged period will cause engine damage (melted pistons and overloaded big end bearings).

 

Pinking is normally a by-product (amongst other things) of running lean!
As mentioned, you should get the mass air flow sensor (MAF) checked out and also the lambda sensor. As the knock sensor is unable to pull back the ignition timing enough to control the det. maybe this should be investigated as well?
It could be something as simple as a hot spot (carbon build-up) in a combustion chamber although with modern fuels, this is fairly rare, these days.
I would certainly use super unleaded in that car.


Check out the breather pipes on the cam covers and crankcase. Not only would you smell oil vapour, you may also allow unmetered air into the induction system.

JohnD

 

Thanks, ive only had the car a month and only just started to open it up fully, having given myself a few weeks to get used to the performance and have a cambelt change done. The car hasnt ever been modified. Also, it had a rolling road test only two weeks ago, they did a health check and it made 200.1HP, which they said was good for a car if its age..shouldnt they have picked something like this up?

 

200 at the wheels? or at the fly?

the cam belt could be out. causing timing issues?

Dave

 

200 at the flywheel, its a 208BHP car with 89000 miles so I was told by Triton (the local subaru specialists in Dorset) that this was quite good as they expect 20-30 BHP less than this for a car of that age. They actually changed the cambelt for me at the same time, so i'd be surprised if it was out

 

My UK MY98 Turbo says on the fuel filler cap SUPER UNLEADED ONLY

 

A good RR operator should have picked up any det that was heard during that session. If the ECU heard det and pulled the ignition advance, you probably lost quite a few bhp. It's amazing how well modern engines maintain their performance as they get older.
Stick a bottle of fuel system cleaner in a tank of V-power. May or may not do anything but won't do any harm, but certainly get those sensors checked out, especially if they're originals.

JohnD

 

They all say that, like the made in Japan sticker. All EU, US, AU and JDM cars use the same filler flap when made at the factory, therefore have the same sticker. But the ECU and engine spec used in them is different.

The manual still states 95RON. Go and have a look.

To further back that up: If it was homologated for use in the UK/EU for 98Ron, it would be rated at 240BHP like the JDM Imprezas of that time, not 208BHP

Either way, the car in standard form should not pink, or detonate on 95Ron fuel. Ever. Unless there is a problem and in which case, it should be investigated.

 

the JDM had a different turbo, maf, etc etc...

not just fuel..

you should run it onm super unleaded not 95ron

 

Why?

The manual states 95RON.

MY98 UK cars are homolgated to run on that fuel.

It is perfectly ok to do so. With no harm whatsoever.

PROVIDED the engine is running ok.

 

Why buy a performance car and run 95 ron in it?

Have you ever analysed what is going on in a std car when running the different fuels? There is a HUGE difference and that's why the petrol cap says Super.

Oh and homologation has nothing to do with it.

 

they are probably fine running on 95 if you are plodding along to the shops or something like that

 

Many cars run quite happily on NUL. My Elise was a performance car and ran on NUL. I expect any car that was meant to run on NUL to run on it as described. Given the stupidly inflated price of SUL all the more reason to run on NUL. Bog standard Imprezas should run on the normal stuff. Are there any mods at all? Could be something like overboost.

 

do 98 cars have a knock sensor? if so is it ok?

 

an Elise is not turbo'd...

I suggest the OP tried super unleaded and see's if it sorts the problem or not..

Simon

 

Its now making a constant screeching sound as well, coming from the front of the engine! I am taking the car in today and will post the diagnosis. Re 95 RON, I know of several people who ran/are running their UK cars on standard fuel, with no problems. The manual definitely says 95 RON or higher.

 

sounds like cambelt issues

 

i always run my impreza on super unleaded,1 it says to on the fuel cap and 2 if i dont then the cel will come on,seriously,u need to run it on super only mate!

 

The owners manual states 95 ron or higher, you can quite happily run a uk 2000 turbo on 95 ron in standard form, though you do get better gains from running 97+.

The only UK cars that NEED super (97+) to run properly are PPP'd cars, the 22B, P1 and STI type UK's.

Tony

 

I know it's not. I said any car which is supposed to run on nul should run on nul without any issues, like a standard uk turbo. My old Elise was another example of a performance car that didn't need sul as someone wrongly assumed you HAVE to run a performance car on sul.

 

I may be wrong, but I think Simon was eluding to the fact that a NA car isn't likely to suffer serious det (if any) if the 'wrong fuel' (and I don't mean diesel lol) is used... COMPARED to a turbo with at least an additional c. 70% of air going in on WOT/max boost

 

This is the point I was addressing, not whether a car is a turbo or not.

 

I agree with you. If any performance car - whether FI or NA - has been optimally mapped on 95, and so long as its ECU doesn't provide for further ignition advance/fueling/boost etc. (for when a higher RON is used), then there is 'no point' in putting in 97 or above.

 

Mine was run on 95RON for years before I bought it. I had diagnostics done...dyno, and then Andy F mapped it. No problems whatsoever caused by using 95RON. Plus it was running about for years with a full decat, and induction kit with no remap. Running rich, but not damaging the engine.

Now has an Apexi ecu and it's spot on.

 

So, is this car running well on 95 ron ?

Why not try SUL and see whether the pinking/det/knock goes away ?

if you want to waste a chunk of the potential performance of your car thats up to you but dont let it det itself to death because the manual says it should run on 95 ron or above. (note the 'above')

 

Dynamix, I'm not sure if that comment was meant for me?

If so, I have only ever run the car on V power, and it's now mapped solely for V power: I was simply pointing out that it had been run for years with no damage on 95RON, as I know the previous owner.

 

No, sorry. It was meant for the OP. His car is detting 'slightly'. If it is loud enough to hear then that is not 'slightly'. For the sake of a few p per litre why kill an engine? Or at least long enough to get it checked out by an expert.

 

I wholeheartedly agree with you dynamix. So despite me saying the above, I'd still personally use 97+... Not for any necessarily hoped-for performance gains, but to act as a kind of 'second line of defence' against det, should - for whatever reason - fueling, air density/temp etc. go slightly awry. At the end of the day, if you put the highest possible available RON in, then you are doing all you reasonably can to try to keep det at bay ... Whereas with lower RON, it possibly could do harm.

For me, it's a no brainer.