Intermittent loss of power Subaru 2.2.

[darbykidd]

Just an update here.

I have yet to replace the starter as I mentioned in my last post, but I did just take the van on a 500 mile trip. The van started and ran just fine. The only code I am now getting is #33 (VSS-Vehicle Speed Sensor)...to be expected with the subaru conversion. I have ordered a VSS to be installed in the speedometer...I'm not exactly sure how to hook it up. I posted another question in a separate thread awhile back and will get to installing it in time. Having the MLI..(Old OXS) light on all the time is kind of annoying, in addition to not knowing when an issue pops up.
Thanks again for all the expert's help. The van is running well but I'm still only getting about 16 mpg.

[Howesight]

Did you repair the exhaust system leak? If not, then that explains the poor fuel mileage. With a leak, the oxygen sensor is exposed to ambient oxygen and adds fuel to trim the (falsely read) "lean" condition.
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'86 Syncro Westy SVX

[darbykidd]

Yes, I did and put a new muffler on as well.

[[email protected]]

Vss should come with instructions. I put the $3 one in. You could temporary disconect light if it bothers you. Once codes get resolved you should be good for a bit

[JeffRobenolt]

ECM's don't like to be outside the vehicle.

Most D Pilar mounted harnesses.sent to me have issues from exposure to the elements.
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[darbykidd]

I’m resurrecting this post of mine as my engine issue has returned.

‘85 Vanagon w/automatic transmission 244k miles
1993 (I think) EJ22 engine. mileage unknown.
VSS installed
I thought I had the van’s engine issues all worked out but the intermittent loss of power is back. It is not throwing any codes during this event. The van seems to run well until I get going over a mountain pass combined with hot 80-85 ambient temps and high throttle. The first symptom is a random hiccup...then a minute or two later another...they progressively get closer together and they last longer until it’s on for a second and then total loss of power for a second, then back on...so on and so forth. It gets very rhythmic. If I let off the gas a little, the pauses become a little less dramatic but still very noticeable. Once I give it more throttle, they become more severe as far as time and depth of loss before power returns. During this time, my water temp raises from about 190-210/220 as expected. Also, interestingly, I noticed my oil pressure drops way down from about 50 to 20....usually I am at idle if it is that low. My RPMs settles around 3000-3500 during these events obviously depending on the hill grade and speed I can hold.

No codes are thrown during these events. Occasionally upon startup I will get a code 35...canister purge solenoid valve...it usually goes away on the next start. I have yet to take care of that. Also, recently once it did stall out on me after extended idling and was difficult to restart. It smelled very rich. Again, no MLI/CEL.
I have replaced the coil. And I recently replaced both of the fuel filters. The pre-filter already appears to have some gunk in it. Could it be that at high throttle setting it is getting fuel starvation from the already clogged new filter? It seems to accelerate fine other times however.
I also suspect the TPS as it passed one test but I got incorrect readings from the second resistor reading from idle to WOT test. 9.9k ohms at idle (normal 12k and at WOT (normal 5k). No change in resistance from idle to WOT. That is what I suspect now, but my ECU is not helping me out with any codes. Any help is appreciated. Thanks.

[slomoracing]

What O2 sensor are you running? My van did totally whacky things when I ran a cheap non Subaru OEM O2 sensor. Also make sure your fuel pressure regulator vacuum line is correctly hooked up.

[Franklinstower]

Something quick and easy to eliminate - get a can of CRC maf cleaner and give your maf a good cleaning. I had a random stumble up hills. Cleaned the maf and the problem went away.

I've suggested this to others with success too!

Paul
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'89 Westy - EJ25/22 Frank 4.44 5mt
'75 Miami Blue Sunroof FI Standard Bug

[Mikesarge]

[[email protected]]

Probably get rid of small square pre filter. Gas tank condition? Fuel pump condition? Could be fuel pump relay. You can get used one on eBay for around $5 or switch out from known good one for a bit.

[darbykidd]

Thanks for the replies...I’m not sure what brand the O2 sensor is but I will see if I can find out.
As far as the fuel filter and pump theory, wouldn’t I get symptoms anytime I have it full throttle?
As far as a fuel relay theory, does another fuel pump relay get opened when at full throttle? I do suspect the tank is cruddy as my new pre-filter (it’s clear) shows gunk already building up. But, if that was the issue I would be having fuel starvation issues anytime I went full throttle correct? I do plan on changing it again soon and cleaning the tank.
I recently cleaned the MAF sensor as suggested but had been driving in dusty conditions recently. I have a new Donaldson air filter as well as a pre-filter on the air intake hose so I should be getting very clean air.

[wesitarz]

Check fuel pressure?

[Howesight]

Reading the described symptoms concerning loss of power at high loads and ambient temperatures, my initial thought was that one of the coils was failing. The symptoms are identical to what happens on my Audi S6 under high boost when an ignition coil is weak. That car is a Coil-On-Plug system.

Since you replaced the coils, then it might be worth checking the coil driver(s). They are also sensitive to heat.

Another thought is that you are possibly experiencing a lot of knock and the knock control system is pulling back ignition advance. Try running a half tank of 94 octane (if you get it in your part of the world) and add a gallon of toluene ($15 at the paint section in Home Depot) to that half tank of gasoline. This will not damage any fuel system component, but it will give you 98 octane fuel. If this solves the problem, then you can start looking for the reason for the increased tendency to knock.

Many Subaru engines are oil drinkers. (I seem to be the lucky one whose EG33 uses no oil.) Under load, the probaility of knock is already increased, and when you add oil-vapour-rich blowby gases into the intake tract, as happens under load, you can get a significantly increased amount of knock. Of course, you don't hear the knock. At the first minor (and therefore quiet) knock event, the knock control circuitry retards spark timing.

You might consider trying a Mann Pro-Vent crankcase ventilation system (or similar from another vendor) to see if that assists. It is worth installing one regardless.
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'86 Syncro Westy SVX

[slomoracing]

Just FYI these are the exact symptoms I had when I had the wrong O2 sensor in. We drove five hours from Denver to Moab, no issues, then the van started dying backfiring and all kinds of random issues. I replaced half of the electrical components before putting a new Denso O2 sensor as recommended to me by Superrupair in Boulder.

[darbykidd]

Sounds like a lot of agreement for an O2 sensor issue so I will be getting a new one soon.

Also, thanks for the suggestion regarding the engine possibly knocking from excessive oil vapor blowby. I’ll try that suggestion for super high octane as well. I came across this thread recently and I’ve been meaning to reroute my pcv valve hose as suggested to minimize oil consumption through it.

https://www.thesamba.com/vw/forum/viewtopic.php?t=564698&highlight=subaru+oil+consumption

I put new plugs in yesterday and decided I’d do a compression test for curiosity. Never done one before, but I think I did it all correct. My numbers seem low though. 142/150/150/155. I don’t think that has anything to do with my stalling issue but thought I’d pass it along.

The van is currently not driveable due to 3 of 4 of my pretty new Rockford CV boots ripping or pulling off during my last trip. For now the van is sitting and it’ll be awhile before I can test it again. One thing after another.