So i have this weird problem, i have a 87 gl wagon ea82 with weber carb. I took off the stock Hitachi and all the emissions stuff: pcv, egr, etc and capped them off. I was getting an intake backfire but ended up fixing this(replaced distributer and fixed ignition timing) After that though, the little rubber caps i have on the extra vacuum spots keep blowing off randomly. No back fires or anything. I'm wondering what’s causing the built up pressure? a couple buddies were thinking cam timing. but everything seems to run great. Any ideas?

backfires in the carb is typical of crossed ign wires.

 

cam theory sounds plausible. you should rotate the engine and check the alignment of the timing belts

You've got your crank case sealed up. That's why pressure is building.

 

There is no reason to cap the PCV system. Hook it back up and you will be fine. It does'nt cause any power loss, and it will make your oil and your engine last longer.

 

At the very least, put filters on the PCV ports on the valve covers so you don't have a sealed case.

cool thanks, ill check wires and cam timing. I think wire's are good though after replacing the distributor(no more intake backfires, well no backfires at all actually)

 

Sorry i didn't explain better, i actually have a breather filter on the pcv port's coming from where the valve covers are. It is only one filter though, i have the two ports connecting into a t connector with a filter(maybe this is causing more pressure then it should?)

 

cam timing was something i wasn't 100% sure i got right when doing timing belts, water pump, head gaskets(i thought maybe i was a tooth off; but it runs so good... lol). I'll double check it and see what i come up with. thanks for the info, ill let you guys know how it goes

Please refer to this diagram for your pcv routing. Since you have 2 cylinder banks, it must flow the right way to be effective.

your one filter probably won't cut it. it needs light vacuum.

Here's some pictures, easier to explain

 

PCV valve hole is plugged with a bolt. vacuum capped here, doesn't pop off though.

 

So far just seems to be these 3 vacuum caps(2 black 1 yellow) that come off. I have the two valve cover PCV ports running to the breather filter.

 

EGR is capped and vacuum advance for distrib isn't hooked up. It seemed to run better with out vacuum advance. I tuned ignition timing after removing the vacuum advance.

 

I haven't checked cam timing yet, I'll probably get a chance by this weekend. I gotta go to the parts store any how can pick up another breather filter. carb hasn't been rebuilt for awhile. :-\

Here's how I setup my PCV system on the EA82 with a Weber. So far it seems to work GREAT. I even put a catch can between the driver's side head and the T to the pcv valve. It keeps some oily and wet stuff from getting into the intake.

 

http://www.ultimatesubaru.org/forum/showpost.php?p=950800&postcount=35

Also, the EGR actually helps extend engine life and keeps emissions down. I'd reinstall it and hook it up to the plugged port on the carb next to the timing advance (it's for EGR).

 

If you do this I'd also hook up the thermo-vacuum switch which screws into the intake next to the thermostat. This switch bleeds air into the egr control vacuums and timing advance, disabling them until the engine is warmed up. I did a little writeup in the same thread the above post is from about that.

 

Oh, it also helps fuel economy when cruising.

Edited April 5, 201114 yr by kanurys

Awesome thanks for the info! gonna try some things this weekend let you know what I figure out

I reworked the PCV and checked cam timing, everything looks good. I am starting to wonder about some leaking valves? i put silicon on caps and so far they havne't blown off. I'm looking into doing the EJ swap now.. so i'm just gonna drive as is for now