ea81 Hitachi carb vacuum routing again

[TajMan]

I've just gotta get my '83 Brat running right again, I've been swapping lots of carbs and engines, and ever since I got this carb on with this vacuum routing it is not set up ideal and does not run right (mostly when it gets to regular temp. or hotter). I KNOW the issue I'm having is simply vacuum routing.

 

EGR is ELIMINATED completely, other stock emission stuff/vacuum routing has gone from different levels of deleted/returned to stock.

This '83 chassis used to be an automatic, now its manual.

 

can you tell me, do I NEED this vacuum port switch whatever it is?

pic#1

(sits bolted on top of this on the intake manifold)

pic#2

I have these 4 small vacuum lines capped off behind the carb there..

pic #3

What is this one? This vacuum device was only on my '83 car, not two other '84 cars or an '86 that I've had here.

pic#4

that sits right back behind the pass. strut tower from factory

pic #5

and lastly how about this?, factory its located by the fuel filter with the thick hose running behind the drivers' strut tower.

pic #6

 

I'd just as soon keep as much stuff eliminated as I can, I just need to get the carb to run right. And its dieseling now, even though the anti-dieseling solenoid is hooked up! argh

[TajMan]

so looking everywhere, I couldn't find my spare vacuum switch from pic #1. Was ready to go get another from the junk yard..

 

After following routing for a second (I've got this 86 engine on the ground out of the car), I decided two of those small tubes capped off coming from the bottom of those 2 black plastic multi-port things.. needed to be 'T'd together with another vacuum source from the intake manifold

 

boom goes the dynamite

It appears to run correct now testing it in the parking lot! And I kept a slight bit more eliminated, excellent.

 

Going to test more on street now.

Its great to have throttle-response, to have the engine NOT-die if you don't carefully jab the throttle accelerating from stopped/idle, to have powerband pull cleanly without spots where the power misses/stalls.

I was spending all my time thinking why the ea81 needs a simple solution to purchase for common rail fuel injection custom intake manifold to be used with something like megasquirt custom engine management.

THEN response characteristics of engine could be set up ideal, and would be ready for a nice supercharger/turbocharger and 200hp reliably mmmmmm

[a2labs]

In my ea82 wagon, the only vacuum related things I have hooked up are:

 

-vacuum advance on distributor

 

-vacuum line to heater controls

 

-charcoal canister to direct fumes from the tank into the intake

 

Pretty sure that's it. The rest of it is emissions crap. One of the first things I did when I got this car was one-by-one eliminate any vacuum line that wasn't critical. It sure made a hell of a difference in the way it runs.

[TajMan]

Well I still need a proper guide on which lines to cap and which lines to vent!

 

I thought I had it fixed, runs pretty good in most situations, but when it gets hot it has some troubles again, not as bad as before.

I feel like that's what that vacuum switch in #1 pic might have been helping?

 

I know you can run with very little if set up properly, I'd rather just eliminate that all..

[a2labs]

I'll try to take some pics/notes of my setup when I weld my new manifolds on tomorrow. I don't think you need any vacuum/vents at all tho.

 

Go back far enough engine wise and there's none. Not talking about Subaru's specifically just engines in general. Points distributor has centrifugal advance, mechanical linkage to control the heater position, usually on/off if there was heat, tank vented thru the cap or not at all. I don't know maybe I'm dreaming all this up. I've been around plenty of old engines and I swear there are no vacuum lines that are critical.

[TajMan]

Well my last post might have spoken too soon, I suppose vacuum T worked,

my engine does seem to run awesome 95% of the time or more now, EVEN in the very hot heat! Pretty great for a stock Hitachi carb, smells like it probably runs rich sometimes at least, obviously not jetted perfect with my much different than stock exhaust.

I do recommend the Weber 32/36 for improvement over stock carb.

I do not know why it diesels for a sec when killed sometimes now when hot, even though the anti-dieseling solenoid should be hooked up, worked before.