My Desmog Thread

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Did you keep the HAC (high altitude compensator) in place?

I am about to pull the carb off and do a re-torque on the intake bolts (recommended after 1000 miles by everyone I have talked to), so I will take some GOOD pics at that point and post them.

No, I did not keep the HAC. I live in Phx and I run a HEI distributor. The HAC won't do much, if anything for me. I figured if I go up to the mountains, it will only take a minute to bump the advance.

I have 300K miles on the truck, unknown on the motor. I was pleasantly surprised that my manifold bolts were tight when I checked them.

Stand by for pics...
 
I just ordered the bolts for the air rail from Jim C. When they get here, I'll be getting back into this project, and this time I'll take the camera with me. This is going to be the goldmine thread for future desmoggers, three of us doing it at the same time
 
What did you use to plug the egr pipe prior to welding it? I'll be doing that soon.

You've probably tackled this already, but maybe it'll help someone in the future...

I took the EGR/PCV thingy with me to the hardware store and found a bolt that was a perfect fit and then JB Welded it in place.(makes a really clean bead!) After it set up, I cut it off flush and painted with hi-temp paint.

Here's a pic of some gaskets that happened to have the EGR thingy in there...
Manifold Gasket 002 (Medium).webp
 
Did you keep the HAC (high altitude compensator) in place?

I am about to pull the carb off and do a re-torque on the intake bolts (recommended after 1000 miles by everyone I have talked to), so I will take some GOOD pics at that point and post them.


I *might* be wrong if you are using the stock exhaust manifold, but you should be able to get to the bolts without pulling the carb. You might need to use a creative mix of extensions, but there are access "tunnels" under the carb insulator plate.

I have no HAC equipment on mine, either.

Yeah, I've been trying to find a muffler shop to do this for me, and it hasn't been working out, maybe I'll just buy a length of exhaust pipe, and cut and attach the flanges myself.....?


I actually had good luck at the local muffler shop, but I only brought them the flanges and gave them the overall length. I didn't tell them what it was for (like they couldn't guess anyway;)). Think I paid $40.
 
Here are a few pics of mine, if anybody needs other pics let me know.

I've since removed the (cracked) headlight washer bottle, so now I have tons of room.
Engine 003 (Medium).webp
Engine 006 (Medium).webp
Engine 009 (Medium).webp
 
Cam,
Are you still using the Vacuum Valve(driverside fender) that connects to the evap system? I can't tell from your pictures.
 
I don't think so... I didn't study the system beforehand so I'm not sure exactly which valve you're talking about. Here's some of the non-used plugs on the driver's fender. The grounded wire was the switch for the decel fuel cut.
Engine 021 (Medium).webp
 
Study these...They will make perfect sense eventually...
72706FJ60desmog.jpg

desmog-richadams.jpg


Drivers side...
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Passenger side...
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Carb (valve cover side) 4 available ports here, I used 2 (distributor advance & old EGR for Evap valve)
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Labeled...Hopefully for clarity. Also included are the choke opener(green) & choke breaker(yellow) on carb
Desmog_notes.jpg

desmog_dr_side.webp
desmog_pass_side.webp
Carb_pass_side.webp
 
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Can you explain how it works in the system? I'm not convinced it's needed. HERE'S a good thread that labels each port/diaphram on the carb. According to JC, HAC and the choke opener are no longer used. Even though it's in the 40's section, the carb is an '87.
 
Note - I suspect B and C are different on my carb and in the JimC desmog diagram above...


Consolidated from Cam's link. Info by JimC (paraphrased here)...

A) Idle Mix...Used for infamous "lean drop" FJ60 carb usually has a metal cap over this (drill out to access)

B) Cap - Decel fuel cut port - Connect to decel fuel cut switch - not used if you ground out your idle solenoid aka "green wire mod"

C) Ported vac to distributor - low vac at idle, increases w/ rpms

D) CAP - If HAC is not used

E) Choke hi-idle screw. Adjust to 1800-2000RPM w/ choke on, engine warm.

F) CAP

G) CAP - More HAC, cap em both.

H) Choke Breaker, Leave hooked up as from factory - to green VTV on carb to middle port top of carb

I) Choke Opener, CAP - Cap if it makes you happy. It's a vac sink, not a source, so doesn't need capped.

J) Base idle speed screw. Set to whatever you like w/ engine warm. ~650 rpm

K) Goes to Evap Cannister - keep - unless you ditch the canister

L) AC Idle up, CAP if you don't have AC. Otherwise gets vacuum from AC idle up VSV on driver fender.

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The above picture is misleading because only three of the four ports on the side of the carb are labeled. The fourth port not labeled is the advancer port and is located under the B port.

Here is how I have mine hooked up:

Advancer port (not labeled)- I use this for dizzy advance, just like the desmog schematic that's floating around.

Port B- I use for fuel decel circuit. Don't have wire mod.

Port C- EGR port, I use this for the EVAP system like the desmog schematic shows.

Port D- Capped not used

HTH-
 
The above picture is misleading because only three of the four ports on the side of the carb are labeled. The fourth port not labeled is the advancer port and is located under the B port.

Here is how I have mine hooked up:

Advancer port (not labeled)- I use this for dizzy advance, just like the desmog schematic that's floating around.

Port B- I use for fuel decel circuit. Don't have wire mod.

Port C- EGR port, I use this for the EVAP system like the desmog schematic shows.

Port D- Capped not used

HTH-
Agreed. That's how I did mine as well. This carb has all 4...
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Carb_ports_JimC.webp
 
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Can you explain how it works in the system? I'm not convinced it's needed. HERE'S a good thread that labels each port/diaphram on the carb. According to JC, HAC and the choke opener are no longer used. Even though it's in the 40's section, the carb is an '87.

you don't need the HAC if you plan on NEVER going to altitude over 3200 feet. That is where it begins to take effect. Or if you live at that level you can just adjust thecarb for that level and get rid of it as well. Some people say they will just adjust the carb if the go that high, bu that seems like a pain in the ass to me

I travel from sea level to over 11,000 feet rather often, so the HAC is something that I NEED.
 
I read this thread and it got me excited so I decided to go ahead and do it. I do have a few questions that I am not clear on.
I decided to post hear instead of a new thread to keep this information all in one thread in case someone has the same questions as me.

1) If I am not going to remove the cat right away can I just plug the air line that runs to it?
2) If my air pump is in good shape and all hoses are removed is it okay to let it be without devaning it (temporarily?
3) My HAC valve does not work and I live at about 5500 ft. Should I just advance the timing a hair and leave the ports open on the carb so it runs a little leaner?
4) Emissions computer - where is it and do I unplug it?
5) Green wire mod - do I do this or hook up the decel fuel port?
6) What is the routing for the primary advance on the distributor, where do I hook up all of the vacuum lines for this advance?

I think that is all, hopefully everything is clear enough. Thanks in advance. Everything has come off smoothly so hopefully I can finish this up tonight.

Brian H.
 
1) That's what I did, seems to be fine
2) Don't see what it would hurt, just going to throw a bunch of air around
3) As long as you're not going to drive up the Wasatch Front you'll probably be OK, it's for big changes in elevation, I kept mine because I live at 4500, but spend some time over 8000.
4) I didn't touch, somebody else jump in here if we need to do something
5) If you have trouble keeping it running when decelerating then do the green wire mod, if you don't then hook up the decel fuel port
6) Look at all the pics and diagrams above, then drive up here to Pocatello, and we'll compare in real life and do a little cruising (it gets lonely up here in Idaho)

I thought you all had smog laws down there in Utah?
 
Thanks for all of the advice, you answered all of my questions.
Except one. Do both bvsv open at the same temp. I broke off the stem on the one I am supposed to use so I was wondering if I could swap them.

I know what you mean about lonely, I only know one person where I live that has a land cruiser that is into them. I could count the number of people I have seen with cruisers here in Cedar on one hand that I have seen in the past 4 1/2 years I have lived here.

Brian H.
 
Clarifying a couple of Fowldar's answers...
3. Yes, that is how to manually operate HAC. Open the three fittings to atmosphere and the carb is leaned out for hi-alt cruising. And twist the dissy about 5-8 degrees.

4. The only thing the emission computer is doing now is controlling decel fuel cut. If the green wire mod is performed, then the computer is completely out of the picture and can be removed.

5. Decel fuel cut is a Good Thing(tm). No downside, so best to keep it.

6. Typically the primary advance is not hooked to anything. The diagram may show it being connected to one of the breather fittings on the air cleaner just to make it look like it is doing something. The secondary (hac) advance is connected to one of the ported vac fittings on the carb.


And last, no the BVSV have different opening temps. Use whichever one you have, it's not super critical.

I'm outta here....:cheers:
 
Thanks,:clap:
That really cleared up everything that I was still a little uncertain about. How important is it to have the dizzy recurved? How different is the engine supposed to sound after a desmog. I have a kind of deeper sound near the exhaust, not necessarily bad sound but a throaty bom, bom, bom, bom. Just wondering if that is normal.

Brian H.
 
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Thanks,:clap:
That really cleared up everything that I was still a little uncertain about. How important is it to have the dizzy recurved? How different is the engine supposed to sound after a desmog. I have a kind of deeper sound near the exhaust, not necessarily bad sound but a throaty bom, bom, bom, bom. Just wondering if that is normal.

Brian H.

Go with a CatBack. i.e. Check to see what shape your CatConverter is in....
 

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