Help w engine stalling - fuel pressure fine, no EFI codes

[etj]

I have a 92 legacy, 2.2L - the engine dies instantly and suddenly, when driving down the road, idling, whatever. It runs strong prior to dying. Problem seems worse when warmed up or on hot days. I'm stumped.

I've replaced plugs, air and fuel filters with no improvement.

I'm getting no EFI codes, which, unless computer itself is bad, ought to rule out most of the sensors. Fuel pressure is fine (i've reproduced problem with pressue gauge attached) and there's no drop in pressure prior to stalling, so that rules out regulator and fuel pump. I've replaced fuel filter, plugs, air filter. Where to look next - ignition? Coil primaries are a little high - about 1.2 ohms when book says around .5-.8 is normal. Secondaries are in spec. Perhaps the ignitor? I don't want to just throw parts at this, but I might raid a boneyard today anyways.

I'd appreciate any ideas. Thanks!

[free5ty1e]

Do you have a 92 Legacy L? SS? (n/a or turbo?)

Does the exhaust smell like fuel after a stall like this? That might indicate an ignition failure of some sort...

I'd also be interested to know what you find at the 'yard, if they have some Subarus, as I'm looking for some parts myself. Where ya located?

[Legacy777]

If I had to guess.....I'd say MAF sensor.

I had similar issues. Tracked the problem for about a year....and was worse during the summer.

[etj]

new plug wires didn't help, but wow, when it runs, it runs real strong.

I'm re-thinking the fuel pressure thing. I cracked open the fuel filler cap and it ran (in the driveway) for over an hour without stalling out. So maybe the cap isn't venting and/or the charcoal canister is clogged. Still, I never noticed a drop in fuel pressure when it stalled. I'm going to drive it a while today with a loose filler cap and see how she does.


I still way open to suggestions I still need to see if i can find an ignitor and coil in the boneyard.

This really has been the best car I've ever owned, honest

[vrg3]

I don't see how failure of the cap to vent or a clogged canister could cause this problem.

After it dies, does it start back up easily?

[etj]

well a failure of the cap to vent could cause vaccuum in the tank as fuel is consumed, making it gradually harder and harder for the engine to pull in fuel. I've seen this a lot in motorcycles and boats (like when i forget to open the vent on my boat motor.)

I know I'm kinda grasping at straws, but the fact that the engine ran for an hour (which it hasn't done in a long time) after I cracked open the cap does support this. Though I wouldhave expected to see a drop in measured fuel pressure which I did not, so who knows?

[etj]

to answer your other question.

[vrg3]

Hmm, I guess I could imagine that, though it's not clear to me why sitting for a moment would resolve the problem enough for the motor to start again.

So you'll start by buying a new cap with a functional relief valve, and then at some point also resolve the clog in the hose going to the canister?

Or maybe it's your fuel pump going. There's actually supposed to be a little bit of vacuum in the tank anyway. Maybe your pump's not strong enough anymore? Hmm, but then you'd expect performance to suffer.

How sudden is the stalling exactly? Is it as if you just turned the key counterclockwise, or do the revs bounce a little before it dies?

[etj]

it usually just dies immediately, like the key was turned off. it really feels like a loss of fuel, but i'm stumped that the fuel pressure doesn't drop prior to it dying.

My wife drove with the cap loose and she said it died immediately once, then was fine for several trips, so that is inconclusive. we haven't gone several trips in a while though.

The primaries on the coil are testing a little high-about 1.2 ohms - so thats a possibility, and my understanding is a failing coil has more problems when warm.

any idea what the symptoms are of an ignitor going bad?

I've kinda run out of the cheap sub-$100 fixes (filters, plugs, etc) and now i wanna be right when i change the expensive bits!

Strange that I'm getting no EFI codes.

[vrg3]

I guess an ignitor going bad might be kind of like this. Like maybe it gets hot enough to fail and then cools off rapidly once relieved of the duty of sparking the coil. I dunno.

1.2 ohms seems a lot high for the primaries... They ought to be like half that. Weird.

Unless a sensor is giving abnormal signals, you usually don't get trouble codes.

[free5ty1e]

Maybe your ignitor isn't transferring it's heat to the chassis. Has the ignitor been removed and re-installed?

[etj]

is there any need for heat sink paste or anything like that? Most of my wrenching is on BMW motorcycles and thats something that happens there.

[vrg3]

I've never seen any official recommendation to use heat sink compound, but I do.

[Bheinen74]

run some fuel injector cleaner through a tank of gas, could be that one injector is a little clogged?????

[Blackbart]

I can send you an ignitor and coil pack if you want to borrow them for troubleshooting, just pay shipping both ways. Got some other parts, too........gas cap, MAF....