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Pete, Technician
Category: Australia Car
Satisfied Customers: 29116
Experience:  Over 17 years diagnosing and repairing various model vehicles with some certifications and training.
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Subaru Forester S: I have a 2006 subaru forester 2.5 non turbo.

Customer Question

I have a 2006 subaru forester 2.5 non turbo. When car starts initially it runs fine. After a couple of minutes it starts to run rough with low power until it warms up fully. No fault codes coming from ECU. I have collected logs and it is showing the timing retarding to -20 when the problem occurs. MAF sensor, MAP sensor, Coil Pack, O2 sensor have all been swapped. I have run car with knock sensor disconnected and collected more logs as a comparison. What could be causing the timing to retard so much or is this normal and the fault lies elsewhere ? I have removed and inspected Cam and Crank sensors, no apparent issues.
Submitted: 4 years ago.
Category: Australia Car
Expert:  Pete replied 4 years ago.
My name is XXXXX XXXXX I am a professional here at Just Answer. I noticed that your question was not getting a response and thought I would see if you still need help with this.

Usually if timing is an issue here a fault code would set in the computer and it doesnt sound like a code is set here.

This may be due to a lean engine running condition causing this here.On initial start up your vehicle will run on presets your computer has calibrated and then as it runs for a short period the computer will start to read more sensors on the engine for operation.

If you have a vacuum leak it may cause this issue cold and then as it warms up this leak may be sealing up,this is most common for intake gaskets leaking sucking in excess air.

If a vacuum leak has not been checked for visually this should be done to see if there is a vacuum leak.You may also want to have the intake smoke tested to see if a leak is found.If a leak is found it will need repaired to correct this here.I would check and see if this is the case here.

Thanks Pete
Customer: replied 4 years ago.

Hi Pete, thanks for your response. Vacuum leaks have been ruled out. Three mechanics have looked at the issue and given up. How does the computer determine a misfire has occurred and attribute it to a particular cylinder ? The reason I ask is when the problem occurs occasionaly it will have pending misfire codes for all cylinders but will never throw a full code as the problem goes away and the computer determines all is good again.

Expert:  Pete replied 4 years ago.
On some vehicles the misfire is calculated by the crank shaft speed with a crank sensor or even a cam sensor to help determine if a misfire is present as well as which cylinder.Some vehicles will give data on misfiring cylinders with a scan tool plugged into the vehicle that has data display on it to monitor misfire data.

Thanks Pete
Customer: replied 4 years ago.

I've taken some logs while the ECU is in Open Loop. I've pulled the A/F sensor plug to keep it in open loop. From the research I have been doing this issue is potentially caused by the ECU and the fix is to reflash it. Are you familiar with what is required to reflash the ECU and where can I obtain a good flash file to load it with ?

Expert:  Pete replied 4 years ago.

I am following up with you to see if you still needed help with your question you had asked.If my help didn't satisfy your question please let me know so we can continue.

Thanks Pete
Customer: replied 4 years ago.

Hi Pete, I'd like some info on reflashing the ECU as per above. Regards,


Expert:  Pete replied 4 years ago.
On every vehicle I have seen that needs to have the computer flashed this had to be done by a dealer with their computer and scan tool that plugs into your vehicle.The charge for this is usually about an hours labor.

You can check around locally to see if any shop can do this as well but usually this has to be done by a dealer.

Thanks Pete
Customer: replied 4 years ago.
Relist: Inaccurate answer.
I know for a fact that ECU can be reflashed without going to a dealer. Expert hasn't tolm me anything that I don't already know.
Expert:  Pete replied 4 years ago.
I apologize my answer wasn't what you were looking for here.

I will opt out and put this question back on the list to see if others can help more.Don't reply to my last post here unless it is a last resort as it will keep the question locked to me.I hope you can get this resolved with ease.

Thanks Pete