geckoz

Two weeks ago, two warning lights came on: check engine and Vehicle Dynamics. Mechanic pulled the plugs and said they were subjected to some kind of fuel additive and suggested to use 98 fuel to clean the system.

This is a second hand car so I had no idea what the previous owner did to the car. I did as suggested. Plugs were changed and I used only 98 fuel for two weeks, when suddenly the same warning lights came on. Check spark plugs. Same story! What the ....!

I refuelled three times at Caltex and twice at Shell. 98 premium only ( no E10!)

And here are the two week old spark plugs :



These have now been replaced and am now refuelling 98 at BP. But what on earth are they putting into the premium fuel? The petrol stations I used are large with high traffic volume. What could be going on?

This is costing me a lot of money and I am still not sure why this is happening. BTW, before the first incident I only used 91 petrol ( no E10 at all). Maybe the previous owner used 98? I am at a loss...

__________________
Yearning for tough driving terrain

guzzla

I'd almost put my money on the fact that it is not the brand of petrol or the octane rating. You are running a non-turbo Forester so anything more than 91 is a waste of money.That still doesn't solve the problem you are facing though. Have you tried different spark plugs?

__________________
07 Forester XT 5 speed 233,000km

Superacerc

Looks like it's burning rich a bit. I've never heard of fuel additives put into normal gasoline causing these kind of issues. Which Codes were you getting? Misfire codes? That's what will help us solve the problem. Gives us a direction to go in.

__________________
e85 on a TD05-20g, suspension and brake upgrades.

crewzer

Were those the correct plugs? The carbon deposits suggest the plugs might be too cold (heat range too high).

The U.S. MY09 OEM non-turbo plugs are NGK Laser Platinum p/n FR5AP-11 (stock # 5463).

HTH,
Jim / crewzer

__________________
12 Forester 2.5X FB25 5MT Premium AWP PZEV
09 Forester 2.5X EJ25 5MT Premium AWP PZEV (sold 7/2011)

adc

High octane fuel allows a slower flame front which (IMHO) can lead to more carbon buildup. But it seems like your plugs might be the wrong heat range.

__________________
Be careful what you wish for.

geckoz

Thread Starter

The only reason I was using 98 was due to first incident when mechanic said it might be some fuel additive. Since I was not using any additive, I thought maybe the previous owner was using some additive. In order to 'clean' injectors etc he suggested to use 98 for few tank fulls. I did.

The spark plugs that were put in are NGK Laser Platinum Premium PFR5B-11 Stock No 2300. BTW, the first set of plugs taken out were exactly the same type, and the Subaru specialist mechanic made no mention of these being the wrong type, but replace with the same types of plugs. So that can't be the problem.

The codes generated were misfiring and 02 code. I will see if I can get the actual codes off my auto electrician today.

Going by the VIN this is a MY09 car although on the rego sticker it states to be MY08. Not sure now which it is LOL, if it makes any difference to the plugs used....

__________________
Yearning for tough driving terrain

Easy Fixer

What you see here is a case of Octane booster residue. Sometimes its just cheaper to take low octane fuel and add a booster to it if the fuel company doesn't sell a lot of high octane gas. No need to use it. Plugs look very new. You can tell because the electros are perfectly square. Make sure the gaps are correct. Ignition problems are best checked with an Oscilloscope. A good shop, and I really mean good, can check it for you. Or you can replace all the parts and hope you get lucky.

geckoz

Thread Starter

Decided to empty the petrol tank and take a look inside. There must be gunk in there still. Will then see how it goes.

If our petrol suppliers were to add octane booster to their low octane fuel and then sell it as 98, then there would be far more cars affected the same way. It appears that so far I'm the lucky one.

I spoke with RACQ and they said they had no other reports, so far, of similar problems like mine.

Shell and Caltex reps phoned me and said that they do not add octane booster to their fuel and they will check on the service stations that I have used. I suspect nothing will come out of it, even if they did discover some additive in their fuel. After all, they would not want to pay all those mechanical repair bills.

__________________
Yearning for tough driving terrain

geckoz

Thread Starter

It will be very interesting to see what the fuel tank reveals on Monday ( can't do it any earlier) and what the spark plugs look like after less than a week inside.

Mostly, I just want my car back running beautifully, strongly, confidently, athletically.... at the moment it still stumbles when coming out of low gear and up to the next..reckon it must be misfiring again...

All will be revealed next week. Stand by, for another thrilling episode of "The Mystery of the Red Collared Spark Plugs!"

__________________
Yearning for tough driving terrain

link1896

The red deposits look like the octane booster Methylcyclopentadienyl manganese tricarbonyl is present. I recall a product, that did not work, was solid mmt tablets designed to be dropped into the fuel tank. Added 0.7ish octane points. Worth looking in the tank as you have planed to do.

On a separate note, I've noticed fuel retailer A's 98 ron only allows a timing advance of +35 degrees, whilst retailer B's 98 ron allows +47degrees and a decent drop in consumption. Anyone else seen this? The lower performing product has a marine nature to its brand.

geckoz

Thread Starter

My question is: why would anyone want to add an octane booster to the tank for a boost of 0.7??? And why would this affect the spark plugs so quickly in the last case just two weeks?

I drove the car for three weeks from the time of purchase and no dramas, then hit the roo and it was away for three weeks, then two days after collection from repairer, it has a hissy fit and the spark plugs are extracted looking red, just like the above.

I just don't understand where the octane booster could have come from and why all good for 3 weeks and then it starts causing trouble after just two weeks?

Is it possible that the previous owner used octane tablets over a longer period of time with no ill effects but it started to accumulate in the tank as some kind of deposit? Does this stuff leave some kind of residue in the tank?

It's just a mystery to me.

__________________
Yearning for tough driving terrain

breedy

i don't s'pose that something was damaged in the accident like oxygen sensor making it run to rich?

geckoz

Thread Starter

Well, one of the more recent codes thrown were related to the O2 sensor, according to my mechanic. But he said before going that way, he'd want to clean out the fuel tank.

Where is the oxygen sensor located? All damage due to collision was in the front area: radiator, Air con, cam pulleys and timing belt. And of course the external body. What is the likelihood, given the location of the oxygen sensor, that it could have been damaged?

Would it be wiser to first replace the O2 sensor and if that doesn't fix it, then go for the tank cleaning?

Whether to clean tank or not is the question. To help answering this is partly dependent on effect of octane booster. Does it leave a residue in the tank and for how long? I haven't used any booster and yet, there is evidence of it having been used, so it must linger somewhere?

I just had a thought that maybe the smash repairer's employees put some in and took it for a spin. I am just guessing.

__________________
Yearning for tough driving terrain

Bassmaker

The front O2 sensor is located in the drivers side down pipe along with an air/fuel ratio sensor as well, roughly behind the front wheel, and is often a cause of the symptoms you have as well as others related to fuelling. You say you hit a roo? If the body was dragged under the car on the drivers side then either or both sensors could very well have been damaged but not broken. Unless the cable is cut/broken, none of the sensors will show a CEL. Over here, these are not too expensive but I know you guys can get hammered for such things.

Check out the link below for location and part number. I'm not sure whether yours is a 2 liter or a 2.5 so I've put both links up, 2L first and then 2.5L. You can back tack these for any other part numbers/locations and maybe order them from Europe or the US if the local price is prohibitive?

http://opposedforces.com/parts/fores...llustration_3/
http://opposedforces.com/parts/fores...llustration_3/

__________________
Scruffy 99 S Turbo. TD04-19T hybrid. DeCat. JGM.

geckoz

Thread Starter

Thanks for the links. It might be worth checking the condition of the 02 sensor. Fortunately, I have learned to find the parts online and buy them there rather than pay a 500% markup from the dealership parts shop.

__________________
Yearning for tough driving terrain