Best timing on Forester

[DDi]

I have a 03 Forester MT with 170k. Replaced timing belt at 145k by my mechanic.

I noticed that sometime the car, when idling, was about 600-700 rpm. I drove cars with stick
before and was told it should be around 900rpm. So I talked to my mechanic. He said the the
best setting is low enough and not to get the engine stall. This way it saves gas when idling
before red light etc..

However I also heard that incorrect timing could cause air/gas mixture problem and might cause
unburn hot gas damage the catalytic converter. Right now I have a check engine light with a
code indicating that the Cat is no good.

I'm wondering, with the computerized control air/gas mixture in the car, does the timing
actually matter?

Would like to have the professional opinion about that.

Thanks in advance.

 

[AS]

Timing in these newer cars can only be adjusted by changing what are
known as the engineering codes in the ECU by means of reprograming or
adjustment with the appropiate tools. I was told by a Subaru tech rep
that they can get fined up to 10 grand if they change those values.

Timing is important, but with a working system, the ECU will take good
care of proper timing.

With respect to the cat converter, it seems that newer subarus dont have
too long lasting cats. There is another thread about this in this ng.

If the idle is stable at the low rpms i see no problem. 900 rpm seems a
lil high to me, 750 for manuals and 850 for autos would be acceptable.
In any case the ECU will drop the rpms as low as possible, as long as
the engine is stable.

For your code, check the O2 sensors first.

Good luck

 

[DDi]

Thanks for the input. That makes me feel better that the timing has nothing to do with the cat
problem. Dealer said the code indicates the cat problem and a different code will get for the
sensor problem.

 

[Nick Lamendola]

Dan,
I just replaced the front O2 sensor on the '99 Legacy Outback w/ 122kmiles.
The check engine light would come on for a while and then shut off. I think
I remeber the code being P420, said catalyic efficiency was low or something
like that. Replacing the front O2 sensor is a lot cheaper than replacing the
catlytic convertor. Light hasn't come back on yet.
-Nick