94 ej in Vanagon dies w/o notice

[blurat1]

  Hi Subaru guys. I have had a 94 Legacy engine in my van for 4 years now with no problems. Recently as I was driving down the rod it just quit like I turned thje key off.

    It restarted after about 3 tries and I drove home. This started to happen whenever and wherever. I changed the ignition switch as suggested by yahoo van subaru group.

 My battery was at the end of usefulness so I bought a new battery. The van ran fine for about 3 weeks and same thing. I checked all the VW problem areas but all the +P points are good all the way to the ecu, same year as engine.

 

   I notice that when I crank the motor, then let the key rest to the on position nothing happens and when I crank the motor, turn the key to the off position, just as I am twisting the key off the engine gives a slight rumble as if wanting to start.

  It seems as thogh when I remove +P from the system while turning the key off something fires the ignition just once and burns one or two cylinders.

 

 This happens every time. If I crank for several seconds and turn the key off I get a much more agressive rumble than if I crank for just a second or two.

 

Yesterday when it wouldnt start in the driveway I was prepared with a test light and body and engine ground were good and all the +P points at the ecu were hot.

 

 At this point I am a bit lost and dont want to just start changing parts.

 

 It seems I had an old vw 40 years ago that would not start when I cranked it and gave the same engine firing as I turned the key to off position. It turned out to be the coil.

 

 However the Subaru motor seems to have more components to the firing system than the old 6 volt vw.

 

 Any thoughts?  I have visually checked, pulled , shaken the engine wiring and had no luck. Just sit for a few minutes and everything is working again.

 

   Thanks

[GeneralDisorder]

Have you read the computer for codes? 

 

GD

[blurat1]

Yes....never any codes. Acts just like I turned the engine off with the key.

[Numbchux]

I'm latching a little onto the symptom that it acts differently when you turn the key all the way off. I'd be testing very carefully your power supply wires. Make sure it's getting powered correctly when on and while cranking. Make sure the relays are working correctly. Make sure the fuel pump is getting good power when it should be.

 

 

I can't quite picture exactly what part or what circuit is your problem. But it seems to me like it's power supply related. Relay, switch, or wiring....very likely where it was integrated into the VW harness.

[Fairtax4me]

Does it have a MAF sensor? Square top with a greenish label on the side?

[GeneralDisorder]

Could be a faulty MAF sensor. They act like that when the get faulty. 

 

You need to check for spark, fuel, etc when it dies and won't restart. 

 

GD

[blurat1]

When it wouldnt start in the driveway I was able to check all the positive connections at the terminal strip I put by the ecu. All required terms had positive juice. I was using the body ground for testing.

 

I have run it with the MAF unplugged, tho accidentally, and got the 31 code. Also a 23 code when I forgot to plug that one in while testing.

 Just cleared the 2 codes a couple hours ago and went on a bit of a trip to Modesto and back. 74 miles round trip. No problems, just fear at every stop light.

 

I do believe it has something to do with the spark. I cant check when I am by myself but I tested , when it wouldnt start, the power with key on and all looked good.

 

I have a fresh engine in the garage I am going to install starting tomorrow. Complete with sensors and everything from air cleaner to exhaust ports. I guess I will put it in and see if something on the motor is at fault. It could be somewhere in the wiring by the ecu as this morning I pulled up the rear seat and gave all the wires a tug. Then it started but it has started on the second or third try several times. Once I had it towed.

 

Thanks for the input. Giving it more thought as I type I think when I have the engine out I will remount all the wires under the seat.

 

Chris

[Fairtax4me]

If the ECU loses MAF signal momentarily it will cut fuel, but will NOT set a code, especially on OBD1 computers.

When the old square top MAF sensors fail, they drop the signal momentarily due to a cracked solder joint. This causes the engine to stall immediately and with no warning.

The MAF can be repaired, but if you have a spare MAF just replace it and see if that fixes the problem.

Edited April 18, 2018 by Fairtax4me

[blurat1]

Thank you, I did not know that. I do have another MAF on the new motor. 

[el_freddo]

Also check/replace the main power relay (brown unit). The can do funny things to the ECU.

 

Other thing that comes to mind is ensuring your cam and crank angle sensors are bolted in properly. I once had my cam angle sensor wiggle out and it cut all running ability of the engine. A bit different to your problem but worth crossing off the list

 

Cheers

 

Bennie

[lmdew]

Check out LoadPro and load the circuit when checking voltage.

You may be reading 13vdc - Battery voltage with no load but if you have poor contacts or green stuff in the wiring it will not carry the load.

[Bushwick]

If it was acting differently with key position, maybe the signal to cut the engine is wonky? i.e. when you normally shut the engine off with the key, maybe it's doing that when it's not supposed to? I suppose it's still factory VW on that end of the wiring/switch?

Edited April 19, 2018 by Bushwick

[blurat1]

Thanks for the replies. All are welcome as I have been working on VW for over 50 years. Put the Sub in the van 5 years ago and nothing ever went wrong, unlike the rest of the unit.

 

Fairtax, I mis spoke. I do not have a spare MAF. I was thinking of the throttlebody. What years interchange on 94 2.2? Or better yet how do I identify a crack to fix if there is one?

 

Bushwick. My first thought was the ignition switch so I replaced it last month along with the battery. The only wiring interface with VW is a positive pole in a box in the engine comp I use for always on requirements. The one black wire from the ignition provides the switched power needed at the ECU. All others in the box are lights etc.

 

El Freddo...Good to hear from my favorite R/R spot. I will check the sensors when I pull the motor.

 

Imdew, never heard of load pro but Ill look it up. 

 

How does the ignition fire the coil? One sensor? Two? Signals the ignitor then fires the coil? I cant seem to find definitive info on this. My thought is when I shut the key off I get one lonely spark when POS is removed.

 

Thanks again' 

  Chris

[Numbchux]

When it wouldnt start in the driveway I was able to check all the positive connections at the terminal strip I put by the ecu. All required terms had positive juice. I was using the body ground for testing.

 

I'm not sure how you have it wired, but I'd be testing right at the relays (ASSuming you're using factory relays, brown 6-pin main, and green-connector 4-pin fuel). Both input and output side of the relays. I might even semi-permanently install a test light on those (after the relay) so I could watch them during operation.

 

How does the ignition fire the coil? One sensor? Two? Signals the ignitor then fires the coil? I cant seem to find definitive info on this. My thought is when I shut the key off I get one lonely spark when POS is removed.

 

ECU signals the igniter/module, which powers the coil. It's wasted spark, so there's 2 signals, one for #1&2, and one for #3&4. Igniter failures on these are VERY rare. Coils happen, but typically you loose one or 2 cylinders, not everything.

 

Factory power supply for the coil is right off the ignition switch, no relay. Might want to check that.

 

 

 

I'm not 100% convinced it's power-supply related. But if you find those test points, and be ready to test them quick when the symptoms arrive, it's probably the easiest and free test you can make.

[blurat1]

Thanks Numbchucks, good info. I got the seat up and the test light handy but not connected. I just raised the back end and drained the water and oil. Pull the motor tomorrow and put the other in. Ill get a good look at the engine wiring when I take this one out. Hopefully I can see evidence of something. 

 

So you are saying that the coil has a hot wire comming from the ignition switch? I dont remember that wire, I will doublecheck.

 

 Thanks

 

Chris

[Numbchux]

Yep. The coil assembly has 3 wires. Power, 1/2 signal and 3/4 signal from the igniter. It's a yellow wire, IIRC the center of the 3 wires, but I could be wrong there.

 

It's a fairly easy wire to miss when initially prepping the harness, obviously you've had it running before, so you must have connected it. The early harnesses I did (including my own), I ran it to the main relay. But before long I left the circuit in tact as it was set up in the Legacy, and powered it right off the switch in the new vehicle.

[blurat1]

I reviewed my wiring last night and compared it to a diagram I found that is quite precise. I mounted the ECU on a piece of plywood along with a terminal strip. My IG on goes to the tem strip and I have jumpers that connect 4 terms to feed all required connections at the ECU. All were hot the last time it failed. I used the original Subaru setup for relays.

  

  After I rummaged around the wires under the seat at the terminal strip the van started up the next try. I figured it was just fluke like always but now am thinking maybe something at that strip since thats the last thing I touched.

[blurat1]

Took the motor out Friday, marking all the wires and taking note of any inconsistencies. There were only two things my brain took special note of,

 

  1: The light grey connector for the cam angle sensor was a bear to disconnect as the little release tang was hard to push down with one hand and pull with the other while balancing on the tube bumper. The dark grey to the crank position sensor was apart as soon as I touched it making me think that it might be loosing connection from time to time. Maybe the engine stops and I crank it a bit and it rattles around and finally connects? I dont know.

 

2: Im too old for this. I spent a few gazing moments into space wondering how I put this all together in the first place.

 

Got the new motor in today, all day job swapping parts from identical motors because they dont fit right , bizaaar.

 

coolant lines and engine mgmt tomorrow. Should run much better. Burned another cat in 2 years. Hopefully the new motor wont eat the next up so soon.

 

Chris

[blurat]

Got the van on the road again with the newer motor, harness etc. Drove a few places on Sunday, 50 miles or so. No problem. On the road this morn got 3 miles and dead. Fired righrt back up went 2 blocks and dead again. Key in on position I can hear the fuel pump for 2 seconds. Cranking and no starting with the same little burp when I turn the key to off. 

  Picked up some aligator clips to make the test lights at the relays and various points.

[Subaru Scott]

Well, at least you've narrowed down several components that aren't the problem.

 

Did you change the ignitor?

 

If you were close, I'd come by with my test light. I love these kinds of mysteries!

 

No really.

[blurat]

I havent changed the ignitor tho I do have another in my box of stuff. My test light is in the back but when I poke around all the hot spots are hot and it starts again.

[Numbchux]

Subaru ignitor is pretty rare, but that sounds like the symptoms I've seen on other vehicles when the ignition module begins to fail. If you have another, I'd swap it in.

 

 

Is yours still bolted to the factory bracket? It uses that bracket as a heat-sync, so that could be the problem.

Edited May 3, 2018 by Numbchux

[el_freddo]

I had a similar issue. Thought it was the igniter so added a heat sink to it (EJ conversion in an L series).

 

Shortly after this with all going well the fuel pump packed it in good and proper. I had suspected the pump was getting too hot/something not working well when the drivetrain temp "got hot" in slow low range sand work.

 

Heat sink on igniter and a new fuel pump sorted my running issues.

 

The fuel pump did give a slow death/stall symptom, not a dead straight cut out as we were only going slow. But when pump gave up on the open road the engine died pretty quickly.

 

Cheers

 

Bennie