Bit of a weird one. At constant revs & partial throttle ( eg motorway cruise ) at around 3.5k there is a *very* mild surge/slow/surge effect. The passenger doesn't notice it - it's that slight. Doesn't happen as far as I can tell at higher or lower revs.

No issues on accelleration, idles fine both warm and cold.

It's a 2001 JDM Forester S/tb with 13k on the clock ~ so more or less a MY00 scoob. Not modded. Run on optimax only.

Any clues ?


Steve

 

Surging happened with the MY99 UK ECU (AE801) but only slightly. It's a bit of an issue with the AE802 ECU that was fitted to the MY00 UK cars.

It improved with the PPP ECU in my old MY99, but every now and again you noticed it!

I'm hoping that an Ecutek remap will clear it completely!!

 

Thanks, no big issue then..

I'll pull up the carpet and check the ECU version when I get a moment.

I did suggest it might need a remap

Steve

 

My MY00 still surges a little but only when cold. I have a TEK2.5 and it still does it.

 

thx 7Foot

 

When cold they all do it because they go closed loop asap for emissions and this is a bit lean for a cold engine.

 

Is it a mapping issue if it occurs when warm then ?

new map > no surge ?


Cheers

Steve

 

It will always be present, its the ecu using closed loop fuel control to maintain stoich, what you feel is the ecu sending the fueling rich to lean to rich etc.

No remap will eliminate for as long as the closed loop control is working.

bob