legacycentral bbs

Ok...here's whats goin' on...

If my Legacy sits overnight, and I go to start it again, it will run, but run like crap (i.e. smoke, rev slow, lope at idle and under acceleration). Now...If I reset the ECU it will run great, just as it did before...My question is why?!?! It is obviously getting fuel when it is running poorly because it smokes, smells waaaaaaaay rich. I was wondering if my coil pack is going out or something?!? Anyways, your educated input is greatly appreciated!

Thanks in advance guys

If you let it warm up, does it run ok?

coolant sensor?

Don't think so guys...because:

1) It will run fine cold after I reset the ECU

and

2) Its not throwing any codes (I.e. Coolant temp sensor)

Unplug your oxygen sensor, reset the ECU, and see how the car runs.

I have kinda done that already...as the car had a faulty O2 until a couple days ago. I replaced it and the problem has not changed, but I am getting better mileage

Hm. Try the same thing with the knock sensor maybe?

Good idea vrg3...per usual

Umm...do you think you could point me in the direction of where the knock sensor is located?

btw...I built the cable for you scantool...but am having probs with the computer acquiring the ROM ID...but we can deal with that later

Thanks man!

knock sensor is on driver side of engine, under the throttle body area. You'll need to do some snakin' and some reachin' to get to it without removing crap, but it is possible. And until you spend a few minutes looking closely for it you won't see it at all

I know somewhere on here there's a photo, in fact I remember finding one that helped me find the sensor a while back. Try searching for "knock sensor" on here and see what comes up.

be carefull around the coolant expansion tank.

i have heard that some people who broke thiers and had coolant drip onto the knock sensor and mess it up.

Oh yeah, the coolant tank - forgot that's usually right over the knock sensor. Mine's been moved for so long that I've forgotten.

Jr.SubaruLvr...please excuse for discounting your post...as I believe you were right!

I wasn't thinking that the coolant sensor could be the culprit because I would reset the ecu and it would be fine...BUT...

Monday night I left the fuse unplugged and I put it back in yesterday morning and the car still ran like crap. After work I went and got a new sensor, and this morning it started great w/o ecu reset.

Anyway...good job for bringing that to my attention, and thanks!

yeah a bad coolant temp sensor can cause utter havoc on how the car runs.