You can delete the cyclic valve and run a manual boost controller.

 

Yes, that's the cycling valve. It's hideously ugly. There are plenty of opportunities for leaks to occur here. Just from looking at the limited lengths of hose in the pics, those hoses are toast. Probably hard as plastic. Right behind the cycling valve is the 'rabbit ears'. The hose that goes from the rabbit ears to the fuzzy looking thing in the back is the heater control valve. These are notorious for dumping coolant everywhere when they break from heat over the years. Right above that are the speed & reference sensor connectors. Be sure to check the wires on both sides of the connectors, as well as the connectors themselves; they tend to get hard and brittle, and will crumble in your fingers if disturbed. Right under the where your camera is there should be the vacuum hard lines. They can be chucked out and replaced with the appropriate silicone hoses, if you want. The round black thing at the bottom of the pic in the middle is the air/oil separator (AOS). It does what pcv systems on other cars do. These cars do not have a 'pcv valve'.

They way the engine is tilted on these cars really does make it a good dirt catching bucket. Without removing the engine and tearing it down, you probably won't get it 100% clean, but at least there's a massive intake manifold that sits right above everything to hide any dirt you may have missed.

Going back to the cycling valve; it looks like it needs to be replaced or deleted. If you do decide to delete it and go with an aftermarket boost controller, keep that connector on top of the CV intact. It is a useful source of switched 12V.

 

At the moment I'm thinking I'll just replace the CV with a new one vs a MBC. Now that the true extent of the vacuum issues under the hood has become apparent, I'm feeling mildly overwhelmed and don't want to introduce a new variable into the mix with trying to adjust a MBC. I think I need to focus just on getting her back to normal functionality before I start trying to change things further.

It also helps that I've already bought new silicone LR hoses for everything except the radiator hose set, so I'll at least be able to get the old ones out of there. I pulled the venturi setup out, and the portion of brake booster hose between the manifold and the check valve actually snapped when I tried to bend it, so it's a good thing it's being replaced!

With all that said, should I be looking for the wastegate closer to the driver side, passenger side, up against the firewall, or what?

 

If you stand next to the the passenger wheel, lean towards the middle of the firewall and shine a light behind the engine toward the passenger side. The WG is down by the bellhousing. You can also just go under the car if you still don't see it, and it will be right there. You can't miss it, unless you don't know what a WG looks like haha.

 

Alrighty, I'm back with an update and question. I'm making progress, slowly but surely: I've yanked almost all the old small vacuum lines, as well as cut off the crimped hose clamps on the hoses that go from the metal tree thing to the J-boot. What a PITA that was; thankfully my compact reciprocating saw with a hacksaw blade was able to reach those clamps. Yeesh.

My latest question concerns the lines attached to the blue/black check valve. There's a line that comes from the fuel vapor diaphragm to the check valve, and from there most diagrams seem to say the line needs to go to the vacuum canister by the battery. My car looks to have some sort of T split to two different lines as shown in the photo below (above the accordion-looking hose); where do these connect to?

 

One should go to the vacuum canister by the battery and the other through the firewall to the climate control.

 

I understand the desire to keep the Cycling Valve: it is, after all, part of an "electronic boost control" system (with the KLR). When my CV's time was up, I found the Lindsay MBC was cheaper, and with everyone talking about using one, I went with that.

The MBC did allow me to clean up the vacuum "tree". I kept the metal lines in though; that one rubber end line on my '88 that leads to the top of the AOS is actually part of the metal tree and can't be easily replaced, at least not with the proper piece that has the vent in it. I've seen one guy grind off the small metal branches of the tree, leaving just the big metal AOS line. Very neat. Deleting the CV also allows you to get rid of its bracket--a very obtrusive and hard to access thing--leaving even more open space after. This engine needs all the open space it can get for future work.

BTW.. the MBC is really just a pressure regulator as found on air compressors. It's very easy to install and adjust.

PS: hopefully, you've already ordered replacement intake gaskets. I find cleaning off the old ones and having new ones on hand the most bothersome part of intake r&r

 

Thanks Perry 951, that's what I was looking for.

Yeah, a MBC or EBC may be in the cards down the line once I'm able to start working on the "fun" upgrades. For now I've got a new cycling valve courtesy of Pelican Parts, replacement hoses for all the various branches of the vacuum tree either already here or shipping soon from Lindsey Racing, and I even scored a vacuum line manifold from Laust to help tidy things up. The only hold-up at this point is some new hard pipe hoses from LR that are on backorder since late August; don't want to start installing the tree hoses until the hard pipes that go underneath them are replaced.

The good news is that the venturi delete/vacuum hose kit I bought from LR included intake gaskets, so those are already on my workstation waiting to be installed.

 

The 1988 tree has an integrated rubber hose (ie. can't buy separately) that goes to the AOS with a special vent fitting. Not sure if earlier versions are the same. I mention this as I don't think the LR replacement comes with this vent. I don't know what the vent does, but it's there (on '88 at least).

Great news on the Laust manifold! Those things are awesome.

Frankly, I kinda like the stock CV.. it's a pretty sophisticated boost control system for the day and keeps the knock control fully intact. Of course, it doesn't let you increase boost... but I find the ball-and-spring controls that install on the line off the intercooler and delay the air a bit (aka "Lindsay Boost Enhancer" or cheap Chinese equivalent) does a super job of giving you more fun.. particularly off-the-line or low-rpm situations... while CV keeps your total boost at stock 12psi or whatever--which ain't *that* bad, really.

I have both a ball-and-spring AND an MBC. The MBC is set around 15psi... a ballpark as it changes a bit based on conditions. Fun and safe

 

Well it's been about a month since the last update, so I thought a final update was warranted after all of the assistance from folks on this thread. So before I continue, a massive thank you to all the people who chimed in on this to help me out; your insights were invaluable to me on this.

So in the last month, the LR intercooler hard pipe hoses finally arrived, as well as the boost control hoses for the cycling valve and vacuum tree. Then it was a slow but careful process to trace the hose routes with string, measure the lengths, and then cut as needed. One thing I discovered was that the hose after the check valve teed off to the climate control as expected, but the other side didn't go to the vacuum reservoir; the PO plugged it into the wastegate! What the hell...anyway, a few pictures:

Before:


Delete that venturi BS


AOS hose, probably shouldn't look like that


The holy grail


Just before intake manifold reinstallation


All buttoned up!


Ended up replacing all of the vacuum lines, IC hoses, cycling valve hoses, cycling valve, check valve, thermo valve, fuel vapor diaphragm, and venturi delete. Now to see if she runs how she's supposed to.

 

Well done! I'm planning to do a similar project to my car this winter while it's up on stands.

 

Nice!!! May the force boost be with you.