FJ60 Desmog Question - Yes another one. (1 Viewer)

[BreckenridgeCruiser]

It's been a while but finally digging into the lingering issues with my FJ60. I have a JimC rebuilt carb installed and have a lingering issue that you all may be able to steer me in the right direction before I start going through system by system.

The issue I am seeing is that I get an RPM drop when I am trying to hold around 1800. When bringing the engine up to 1800, it will get there and then drop down suddenly to around 12 and then climb back to 18 and then will repeat until I either ease off the fuel or give it more to get above 2000 where it will run more smoothly.

Any quick thoughts on where to begin looking?

Also, does @FJ40Jim still offer the desmog kits with all of the hoses and plugs needed to make sure everything is in good shape? I am sure some of my hoses are SAE and may be sources of slight vacuum leaks. if you do please PM me as I would also like to discuss Distributor rebuilds as well. I am operating on my secondary advance as my primary is not working.

Thanks for the help! I did search, but my MudFu is weak as I have not been on for a long while.

 

[mwebfj60]

Maybe verify the vacuum for the ICS diaghragm is coming off the correct port on the carb.
Have you removed EGR, and Air Injection systems?

 

[BreckenridgeCruiser]

More info...
Desmogged rig was done by someone without much knowledge... Looks like I am missing the Vacuum Switch that comes off of the fuel cut port completely. that port on the carb is capped. I will drive to the storage unit and dig through my parts stash to dig one out tomorrow.

Does anyone have a good picture of the switch and more importantly, the plug it plugs into so that I can make sure sure I am hooking it back up correctly?

 

[chichiflys]

Did you take a look see at the FJ60 FAQs?
Smog issues

Smog pump rebuilds and emergency fixes

Emission System demons

Removing Smog?

Why do I have to recurve my distributor after desmog

Silicone Air Injector Pump Hoses

 

[OSS]

The RPM occilation between 1800-1200 could very likely be a faulty vacuum switch. Test its function as described in the emissions FSM. See attached.

If the vacuum switch is faulty, ground it's wire to the body (shiny metal, not paint).

 

[FJ40Jim]

The OP States the vac switch is missing.
So that is faulty, in a way.

 

[BreckenridgeCruiser]

Ha! That's one way to put it @FJ40Jim ! This is the third desmog I've seen that they took that out! Why does everyone overlook this!

I'm heading to the storage to see if it's in my magical store of smog crap. I have two trucks of smog equipment so I should at least have one!

Will report back soon!

 

[BreckenridgeCruiser]

Okay... Grabbed the switch. One question for the guys that really know this system.

From what I can see, the switch is pulled open (therefore open circuit) when at high vacuum... The rest of the time the switch and circuit are closed, there by grounding that connection to the computer.

I only have one wire to the switch so I assume the switch is grounded through the mount. Is this correct?

If so, what is the best way to mount this without having to put all of the crap and brackets back in?

 

[BreckenridgeCruiser]

Oh... And as another question... Has anyone desmogged a truck, left all of the disconnected stuff in the truck to pass a visual inspection but only had the necessary systems actually hooked up, and passed a sniff test smog check?

I know people may not want to post this publicly so feel free to pm me if you have done this, or if you can tell me why this would never work.

Thanks!

 

[mwebfj60]

Okay... Grabbed the switch. One question for the guys that really know this system.

From what I can see, the switch is pulled open (therefore open circuit) when at high vacuum... The rest of the time the switch and circuit are closed, there by grounding that connection to the computer.

I only have one wire to the switch so I assume the switch is grounded through the mount. Is this correct?

If so, what is the best way to mount this without having to put all of the crap and brackets back in?

You got it, grounded through the mount and supplies that ground to the computer. High vacuum pulls it to open...and RPM greater than 1800 takes away the ground to the Idle Cut Solenoid...closing it, and blocking the primary slow circuit off.
I ended up using just a portion of the original mount. I also ran a 2nd ground from that mounting bolt to another spot on the fender (not necessary but what could it hurt right?).

An easy test would be to just ground the wire that goes to the switch and see if it clears up the issue.

Edit...unless the ICS pigtail has been cut and grounded, then this switch doesn’t matter anymore. Just have to make sure there is 12V at the green connector.

 

[OSS]

Being a 30 year veteran of the "war", I can tell you that it's not worth the trouble ripping all that stuff out of there only to reinstall it again at inspection time. It's madness. If the truck has to be tested in the future, it's best to leave all the stuff in there and between tests, if desired, just plug a few vacumm hoses.

The sniffer wil fail the test if the gear isn't functioning.

Ripping all that gear out of there (vs plugging a few vacumm hoses) only accomplishes a visual improvement. The engine won't run any better. It does improve arm access to the driver's side of the engine bay- but once you pull all that crap out of that side of the engine, you'll see that there's nothing to tinker with on that side anyway.

My vote:
If a vehicle has to be tested in the future, don't remove the gear.
If the vehicle resides in a state that is test free- pull the stuff out if you want. But know that in the future it may make the cruiser a lot less desirable when it comes time to sell it again.

The vacuum actuated plumbing of the emissions components on the 2F is the most complicated of any vehicle ever produced. It was an end of an era before EFI. I can tell you that if you rip it all out, chances are extremely good that you'll likely never be able to hook it all back up again correctly unless you're the type that enjoys reading technical manuals from cover to cover over and over again. If you're not the type of person who enjoys pondering the chemistry of EGR, Air Injection and Oxidation Catalyst while going on a long hike outdoors - while daydreaming... Don't do it!

 

[BreckenridgeCruiser]

@OSS, Thanks for your insight! Unfortunately the truck is already desmogged. The good part is that I have all of the parts still and that the truck is registered in a no-smog area so I can maintain registration as it is. I was more thinking of what you mentioned that selling the truck would be limited due to the smog status. While I am actually one that likes to read manuals and does take long hikes (when I was in CO - and I tend to use those times to crunch pesky problems in my head) I would like to avoid putting all of that crap back in if possible.

I will try the ground wire test today. If it works, I will look to some kind of bracket like the one you have in the picture to organize it all. @mwebfj60 I assume that is an FJ40 bracket? Or is that part of an FJ60 bracket you took apart?

 

[BreckenridgeCruiser]

Ha! Sorry... Missed that you said you reused the mount! Ignore my jumping the gun! I was reading it on my phone.

 

[BreckenridgeCruiser]

Ground test wire worked... Going to do the same bracket work as @mwebfj60 and mount that today.

One question for you mwebfj60. I noticed that you still have two VSVs on your bracket. I am only running one (the one with both ports parallel) and not the second one you have (ports at 90 degrees to each other). In my diagram, those should be for AI and other smog stuff that I have removed... Do you have it for something else?

 

[mwebfj60]

Ground test wire worked... Going to do the same bracket work as @mwebfj60 and mount that today.

One question for you mwebfj60. I noticed that you still have two VSVs on your bracket. I am only running one (the one with both ports parallel) and not the second one you have (ports at 90 degrees to each other). In my diagram, those should be for AI and other smog stuff that I have removed... Do you have it for something else?

Good stuff. Yeah, that 2nd one is for an HAC setup.

 

[BreckenridgeCruiser]

What is the HAC setup? I drive up to the mountains and wanted to put mine back in... Does your system make the HAC function better?

 

[mattressking]

Good stuff. Yeah, that 2nd one is for an HAC setup.

To piggyback off this...the egr VSV (which it appears you are using for HAC) you have the cap on port G. My currently smogged truck seems to have a stumble when I have port g vented back into the intake OR capped off. If I vent the port, to atmosphere, no stumble. I'm under the assumption that it should be vented to intake, but are you aware of when it actually vents? Emissions fsm doesn't go into detail about port G.

 

[mwebfj60]

What is the HAC setup? I drive up to the mountains and wanted to put mine back in... Does your system make the HAC function better?

I use it to stop the slight 1/2” vacuum leak at low altitude. Not necessary. It is in between the gas filter and the HAC. When I get to altitude, I have a switch in the dash I push and it opens the VSV. Doesn’t improve the function of the HAC any.

 

[mwebfj60]

To piggyback off this...the egr VSV (which it appears you are using for HAC) you have the cap on port G. My currently smogged truck seems to have a stumble when I have port g vented back into the intake OR capped off. If I vent the port, to atmosphere, no stumble. I'm under the assumption that it should be vented to intake, but are you aware of when it actually vents? Emissions fsm doesn't go into detail about port G.

If you are talking about the VSV in the middle, the cap on the back is a filter that is open to atmosphere.