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2002 Forester
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4 Posts
Discussion Starter #1
Hi All,

New to the forums. Have a 2002 Forester, base model, that in the recent heat wave in Australia (NSW/VIC border region) has started showing odd behaviour when under stress (i.e. up hills, accelerating, etc). I'll try summarise the issue

On a recent trip from Melbourne up the hume highway, the outside temperature was ~45 degrees C. Just got out of the city and popped on cruise control. The first decent hill we came to, the car attempts to down change gear to provide more power and suddenly I'm losing speed and the revs drop quickly. It gets to ~80 kph regains and then tries to accelerate again before repeating the drop in revs and power.

Limped the car into a servo nearby, let it cool and got RACV out. Nothing apparent. Huge outside temp change happened (from 45 deg to 25 deg in 5 minutes). Continued the drive, got over the hills and the outside temp climbed again. About an hour into the drive, up another hill it started again. Limped to another servo, waited there till dark and managed the last 1.5 hrs drive with no further issue.

Had it at the mechanics twice now, replaced fuel pump, still happening. Taking it back to the mechanics again in a few days (country town, not many mechanics...). Wondering if anyone on here might have any ideas. The video in the link was from yesterday, again high outside temp, started this when I tried to accelerate from 80 kph to 100 kph and then continued at low speed. This morning, no issues. No engine lights/dash warnings, no codes.

I'll try pop in a video it happening shortly.

Thanks for any help
 

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Registered
2010 Forester Diesel 6MT
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859 Posts
In the old days that would have probably been 'vapour lock' and is caused by fuel evaporating in the fuel system due to heat.

It may help to clean/replace the fuel filter and check other fuel system components and the actual fuel pressure. Check also that the evaporation control system is working properly and not blocked. Might be worth popping the fuel tank cap next time it happens and see how bad the pressure difference is, whether it is positive (blocked fuel evap system) or negative (blocked breather system, vacuum preventing fuel being drawn after a while) and whether it makes the problem go away.

It does sound like a fuel starvation issue if it's cutting out at higher revs under load. That said, it's possible that could still be something else, e.g. an ignition issue or perhaps a faulty sensor (MAP/MAF), maybe even TPS.

I haven't seen a video link?
 

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Registered
2002 Forester
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4 Posts
Discussion Starter #3
Thanks for the feedback. Unfortunately I can't post the video, haven't made enough posts to put links in 😞

Got the car heading into the shop in a few days. Will give your suggestions re fuel cap if/when it happens again.
 

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2005 Forester EJ251
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122 Posts
I have an MX5 to compliment my Forester. In heat, the MX5 can give stop start hesitation and completely stall. When cool - no problems. This happens when the car has travelled 100 to 120 thousand km. The fault is the cam position sensor. A quick fix is to pour water on it. The mechanics can say the sensor shouldn't cause the fault but everyone who replaces the sensor fixes the problem. I now carry a spare sensor. I don't think any fault codes are stored for this fault. Perhaps you have a similar sensor problem.
 

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Registered
2002 Forester
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4 Posts
Discussion Starter #7
Looks like it was a fuel pressure situation. Pressure gauge on the fuel line showed some behaviour. New fuel pump and some cleaning, worked out under an hours driving in 40+ heat.

Fingers crossed that's got it. Thanks for the advice!
 

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Registered
2010 Forester Diesel 6MT
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859 Posts
Great news Talismutt. Wishing you many klms of happy and trouble-free driving! :smile:
 
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