Dies hitting boost after harness swap(UPDATE) FIXED!!

[alexandermf]

Update on last page, cars been down forever one thing after another, need serious subie guru advice!


So my car just randomly shut off mid drive on the highway, no sputtering no nothing. At first it was cranking just not starting. We weren't getting any spark and we ruled out battery and alternator. Tried a new coilpack, still no spark. We towed it to my mechanics house where we did diagnosing alllll Damn day. So far we have replaced the cam and crank pos sensors and that didn't work.

Next we checked the fuel pump. We ate getting power to the fuel pump but its trickling out of the fuel lines so barely any fuel pressure. We took pump out and hot wired it and it turned on. So that lead us to the fuel pump relay, after digging that pos out and replacing that and the ignition control module still no spark.... Last thing we are trying g today is a new fuel pump and if that doesn't work the only thing left I can think is the ecu which hopefully its the fuel pump just not creating/holding fuel pressure.

Any other suggestions from anyone here? We have been at this for two days now

Sent from your bathroom closet

[alexandermf]

I'm gonna go ahead and throw in a new fuel filter along with pump as well but even if my filter is semi clogged I should still be getting spark and fuel

Oh ya the plugs are all new as well
The car has been running fine previously before, no cel, no harsh idles and no dying

Sent from your bathroom closet

[turbo970]

did you check the timing belt

[alexandermf]

Timing belt looks/feels fine, haven't done one on the car yet since I've had it though(6 months now)

Sent from your bathroom closet

[turbo970]

it doesn't me it didn't jump a tooth and threw off the timing. if i remember right if your timing is off then the crank sensor doesnt know when to let the ecu to fire

[alexandermf]

Hmm well I guess that's what we will check next if the fuel pump/filter don't work

Sent from your bathroom closet

[alexandermf]

Well f*** tits, the new fuel pump didn't solve it! This is seriously sooo frustrating.

So now there is still no power to pump... Gonna have to check with a test light the fuel pump relay that I replaced. Oh ya the timing is fine, we took the covers off and checked

Sent from your bathroom closet

[oldscoobyturbo]

check the ground to the fuel pump wiring and the harness under the back seat. Could also be the fuses sbf2 and #23

[Legacy777]

Does the CEL come on when the key is in the ON position (engine not running)?

If not, you've got an ECU or power supply issue. Even if the light comes on....I don't know if I'd say you can totally rule out the ECU, but the fact it comes on means the ECU is getting power.

[alexandermf]

No CEL in on position... Or do u mean does it light up in general with all the other dash lights like abs, etc?

I'll check grounding wires and those fuses tomorrow, what do those fuses pertain to exactly?

Sent from your bathroom closet

[Legacy777]

Yes, I mean does it light up with the other dash lights. It should be lit up solid when the key in the ON position and engine not running.

[oldscoobyturbo]

the ground and fuses might not be working or blown. i've redone a few bad grounds with my cars also had to replace a bad relay and fuse at the same time i put in a new walbro pump to be sure

[alexandermf]

Yes the cel light comes up solid like all the other lights. My buddy has a scanner he's bringing in the morning which should hopefully read something.... If not ill check the fuses

Sent from your bathroom closet

[MConte05]

Timing belt.

My timing belt skipped in the middle of January in northern MI the night before the Sno*Drift rally. I was cruising back to our hotel after unloading the car off the trailer and the car just shutdown randomly. No amount of pop starting while it was slowing down was getting it going. I thought it might have been our alternator because I was running the heat on full blast, all the lights on high-beams and my huge light pod as well. Swapped that on the side of the road with no avail, no jump starting helped. Flat towed back to the hotel and reset the timing belt at 1am. Fired right up after that.

So yea.... timing belt probably skipped. Pretty easy to reset though if you know what you are doing. Just remember the push the tensioner allllll the way to the left (use a long Phillips head screwdriver to help) before tightening it and releasing the pin.

BTW, it is going to be incredibly hard to check that the timing is fine via visual inspection. Unless you can verify that both sprockets are at TDC when the crank is at TDC. Taking off only one side of the sprocket covers won't help. If anything I'd just take it all off and reset it just to completely 100% rule that out. Just remember to reset to the mark on the back of the sprocket, not the arrow on the front of it.

[alexandermf]

Update... The cel light IS not turning on with rest of dash lights and our scanner can't even connect to the cars computer. Do I need a new ecu? Sorry for late replies and updates but I'm just relaying info to my buddy who's working on the car while I'm at school/work

Sent from your bathroom closet

[alexandermf]

So looks like ill be needing an ecu asap

Sent from your bathroom closet

[alexandermf]

Bought a used ecu for a 5sp but should work with my auto. Hopefully this is the fix cuz we've done everything else!

Sent from your bathroom closet

[Legacy777]

Refresh my memory, but is your Legacy a turbo or non-turbo?

[alexandermf]

Turbo

Sent from your bathroom closet

[Legacy777]

Yeah it shouldn't matter then whether the ECU is out of manual or auto.

[alexandermf]

That's what I thought, thanks for help and confirmation! Been researching similar threads all day and seen your posts and advice in them all lol

Sent from your bathroom closet

[alexandermf]

well i HOPE someone can chime in,... its still been weeks and my subie still wont start! my mechanic and other friend are completely stumped and have never seen anything like this

parts replaced:
ecu
crank/cam sensors
timing belt
ignition control module
ignition and fuel pump relay
fuel pump

checked:
engine grounds
fuses
wire shorts

if anyone has any idea what else it could be plz feel free to post! im going crazy and broke

[turbo970]

did they check compression?

[alexandermf]

Not that I know of but its cranking with compression... Just no spark

Sent from your bathroom closet

[Legacy777]

I would suggest checking for ignition signal/pulse at the ECU before the igniter, then after the igniter, and then from the coil pack. If you do that, you should be able to narrow down where your problem is.