yukonjack

I've been replacing the missing emissions equipment on a recently purchased '87 4x4. This truck has an earlier 22R engine (I think it's from an 84) instead of it's original 22RE. Many of the vacuum lines from the carb were simply plugged, and I'm not convinced the others were actually in the right location. Thanks to Chilton and Haynes I have a good idea of the general routing of vacuum lines, the only problem is the diagrams aren't detailed enough at the carburetor. There are several pictures showing lines running to the passenger side of the carb, but it's not obvious which of the 7 vacuum connections each line uses. So I've attached a (bad) picture of the passenger side of the carb, with vacuum connections labelled 1-7, in hopes that someone can label them for me! I guess 1-3 are HAC connections, and I'm led to believe two of the others are EGR connections, while one is a fuel cutoff. The final one I have no idea at all. Thanks much! Rob v.

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the_supernerd

It appears to be federal smog, not California, is that correct? If so, 1-3 are for the HAC system, according to the 1987 FSM. 5 should be attached to the metal lines like the others are. It should be on the 3rd line from the firewall. It is hard to tell what each one eventually goes to through the metal lines, but I will tell you what I can.

The fuel cut line goes to the vacuum swith on the passenger fender. It will also go to the sub-diaphram on the vacuum advance, which is the port closest to the distributor. It will only have vacuum at idle and no vacuum any higher.

Two of them will go to the EGR vacuum modulator. The EGR port will have vacuum at partial throttle and goes to port P on the EGR vacuum modulator. The other one, the R port, has vacuum at more throttle than the EGR port and goes to the R port on the modulator. The Q port on the modulator goes to the BVSV on the manifold and then to the EGR valve.

The last port goes to the main diaphram on the vacuum advance. It should have vacuum at partial throttle.

There is a lot more information in the FSM, so just ask!

yukonjack

Thank you Anthony!

Yes, this is federal, not CA. That's very helpful, the auto-store fix-it manuals have a lot of info but certainly not that detailed. What I'm still missing though is which port is which on the carb. You refer to the P,Q, and R ports: are they labelled as such on the carb and I'm just not seeing it? Once I know that, I think I'll be good to go! Thanks again.

Rob v.

the_supernerd

They are probably not labeled on the carb. If all of the lines coming out of the carb are attached to the proper places on the metal lines, which it looks like they are, then you should be able to find the ports near the vacuum modulator. It should have the ports labeled on it. Do you have a vacuum modulator or is it missing? It should be between the firewall and the carburetor next to the EGR valve. Feel the steel ports near the modulator while slowly revving the engine to see when they have vacuum. Port P will have vacuum at less throttle than the R port.

yukonjack

Thanks again for the help so far. Going with your info and the diagrams I have, I'm fairly certain I have it 90% correct. There are a few things that still don't add up though:

My EGR modulator appears to only have one port out to the rest of the emissions system. The closest match from my manuals is '85/'86 California emissions, but those pictures show only an EGR valve, no modulator. These show the vacuum line from carb -> BVSV on manifold -> EGR valve. Any ideas on this? I'll be reading the EGR sections in depth very soon, hopefully that will shed some more light on this.

I also have a 4-nipple VCV, which seems to only match Federal/Canada diagrams. The literature itself references the VCV once, but for Land Cruisers only, not trucks (and the picture is not the one I have). I've attached a photo: #1 and #4 connections seem to go (according to some diagrams) to the nipple below, while #3 goes to the ASV. The #2 has a vacuum line going off into space in all my diagrams, any idea where this one leads? Also, the diagrams which show 1,4 attaching to that nipple also show a 3rd connection leading off to EGR land. It seems to imply that thing below (do we have a name for it?) has three nipples arranged vertically, instead of the single nipple I have.

Wow, this stuff is confusing when your engine doesn't match any of the pictures The net result so far is this: with everything connected the way several diagrams seem to imply, I have one unused vacuum port on the side of the carb (of the 4 I mentioned in the first post) and the #2 position of the VCV is also unused. I have these both plugged, but the engine idles very rough and dies -- however it sounds great with a little gas at 1500rpm and more.

Previous to me playing with everything, it ran ok but sometimes seemed sputtery under load (and also failed the loaded CO test.) Hopefully I'm getting close!

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the_supernerd

The modulator should have three ports on it. I am thinking that someone may have mixed some parts from different years or models. You might need to go to a junkyard and get the correct one. Do not forget to hook up the hose on the bottom of the modulator along with the three on the top.

My FSM has a VCV in the vacuum diagram. Hose 2 appears to go to the air cleaner housing and 3 goes to the ASV. 1 and 4 both go to the manifold, so they appear to be in the correct place. 4 should have a VTV on the line between the VCV and the manifold.

A VCV is only for federal smog. California uses a feedback computer to control smog. There should be a vacuum diagram on your hood where it says the tune-up specifications that might help. An incorrect EGR modulator would probably cause your truck to not pass a CO test when under load.

The number 4 port on the carburetor appears to go to the sub diaphram on the distributor, but I cannot tell for sure. Not having vacuum to that would make it idle rough. The line from the 4th port on the carburetor should go to a metal vacuum line where most of the other ones go.

yukonjack

Success!

After trying many times to duplicate multiple diagrams worth of vacuum layouts, I finally decided to do my own thing. I left the same EGR modulator, and only have one line running to it, through the BVSV on the manifold, the other EGR port is simply plugged on the carburetor.

Fuel cut port is just like you said, as is the distributor main diaphragm port. This ended up leaving two nipples unused on the VCV, which I also plugged. (There was no home for #2 on the air cleaner end)

Long story short, it passed emissions by a good margin on most tests, still a bit close on the loaded CO, but good enough for the state of AZ. (and about 1/3 what it was when I first took it through).

Thanks again for all the help!

Rob v.

the_supernerd

Glad it passed smog! By the way, I was looking something up in my manual tonight and noticed the the modulator on a 22RTE only has two ports on it, so that must be what your modulator is from. I am not sure if the correct one would do you any good, but if you are ever at a wrecking yard you might want to pick one up.