My Desmog Thread

[bigDcruiser]

alright, filled the tank this morning for the first time since the desmog. she's been running ok aside from the annoying squeal but i just went out and opened the gas cap and fuel poured out. too much pressure to the tank? i'm assuming it's a vac line connected wrong. any ideas which one? also started her up and thought i heard a slight pop (more like a small puff of air) under the glove box. dizzy vac misconnected too i assume. any pointers? going back through the thread but with 30 pgs now and a few variations of desmog it gets confusing. i pulled egr, cooler, hac and anything else that seemed unnecessary.

 

[Brock]

for the pop near glove box..make sure you have the line on the dizzy correct and that you kept the filter that it goes into....it keeps fuel from going down the line to dizzy and then that pop is the fumes exploding from spark. LOL I think the blue portion goes towards carb so that it can pull vacuum but wont allow back flow into cap.

for the gas tank...I am not sure but I think there is a line that goes to charcoal canister and if put back wrong or plugged you will get excess pressure in tank. hopefully others will chime in on this part for you...as I am not sure.

 

[FJ40Jim]

To relieve gas tank pressure I suggest switching the lines at the canister so the hose from the tank is connected to the fitting on canister labeled "purge". And the purge hose is connected to "tank".

Pop in the cabin is definitely a problem w/ dissy cap ventilation system.

 

[GLTHFJ60]

Had some very weird problems today. Truck has been running pretty well lately, a little better with the warmer weather. I left to drive home from school today and put $20 in at a fuel station to get me to a cheaper one. When I took the gas cap off, I got an excessive burst of fumes, waaaay more than usual. Other than that it was fine. Put fuel in it, drove 50 miles down the road ( almost empty at this point, running just fine ) and filled it up on the highway. Got a bunch more fumes when I opened the cap. Not sure if that matters but to me that indicates excessive tank pressure.

Drove 90 miles down the highway and it started bucking and loosing all power, felt just like it ran out of gas, but I was at half a tank. I managed to get over to a rest area and took a quick glance of the lines to make sure they weren't leaking, all good there. I went to go blow the filter out in case something had clogged it and when I took off the supply line to the filter, gas began rushing out. I had to keep my thumb on the line to prevent gas from pouring all over. I blew out the filter and hooked it back up, same fuel starvation problem.

Since I was at a gas station and the problem wasn't happening when the tank was above half full, I filled it back up. Guess what? The truck ran just fine!!! I'm assuming that this is a problem with the EVAP system ( which is hooked up in stock configuration after desmog ) pushing too much pressure into my tank. Maybe the EVAP VCV went bad?

I usually don't ask for rapid responses, but I was planning on going to the FJNE Northeast event this weekend and already paid my registration fee. I'd rather not go down to PA if this is going to be a concern so I have one day to fix this. Thanks for your help!!

 

[FJ40Jim]

Excessive tank pressure will not make the truck buck and starve for fuel.

To relieve the excessive tank pressure, switch the 2 hoses on top of the canister, so the hose from the tank is connected to the canister fitting labeled "purge", and hose to engine is connected to "tank" fitting.

 

[GLTHFJ60]

Excessive tank pressure will not make the truck buck and starve for fuel.

To relieve the excessive tank pressure, switch the 2 hoses on top of the canister, so the hose from the tank is connected to the canister fitting labeled "purge", and hose to engine is connected to "tank" fitting.

I figured I was reaching with that, oh well. Swapped the canister lines and replaced some old vacuum limes and caps today. Seems to be running fine for now.

Thanks Jim!

 

[rckhound]

Hey Jim C- My truck has been running good for a while now getting me through winter and no more manifold leaks (thank god), but I still have a couple questions. I set my timing at 20 advanced per your 18 -20 recommendation since I live at 10,000ft but I while driving it still smells like it is running rich? Also The engine does not seem to run as smoothly until I reach about 1,200rpms and then smooths out? Timing problem? Also I have been reading about the excess tank pressure problem, every time I open my gas tank there is a lot of pressure, while doing my desmog I found the little rubber elbo on top of the carcoal canister severed and replaced it with a normal piece of house that is slightly pinched at the bend, could this cause the problem or should a switch hoses as per your recommendation above. Thanks for all your help.

 

[FJ40Jim]

Hound,
Generally smell is notoriously inaccurtate as a mixture guide. A lean engine is stinky because of the high HC. A rich engine has low HC and high CO. Humans can't smell CO.

Replace the cenister vent elbow with the molded part from the toyota dealer. It is readily available.

Yes, swap the hoses on top of the canister to alleviate the tank pressure problems.

 

[laguna80]

About to start my desmog and I have a question. If my smog pump is working properly, is it necessary to devane it for a successful desmog? I'm tempted to leave it as is and continue rerouting tubes etc...

 

[FJ40Jim]

Not necessary.

But there are two good reasons do devane.
1. when the pump fails, the problem is always the vanes get jammed inside, bending the rotor, locking up the pump. By removing the failure prone plastic vanes, the pump should last a long time.
2. The vanes use power. An air pump uses power in proportion to the square of the speed. It doesn't use much power at idle, but it starts to siphon off noticeable power at 3200RPM, just when the truck is flying up a freeway entrance ramp and that extra couple of HP is needed.

 

[laguna80]

We can go past 3000 RPM's? ;p

(Thanks, that's good info.)

 

[laguna80]

Nearly pulled everything out but ran out of daylight. Still have to remove the smog pump and de-vane. My thumbs are throbbing right now. That compartment looks sooo much emptier now...quite amazing. Anyway, still need to figure out what to do with the tube coming out of the egr cooler and connecting to the manifold. I think it's safe to assume that I won't be welding in the engine compartment and I think the jb weld won't hold in that area. Otherwise, I've replaced a bunch of tubing and with some hard work, I'll be finished tomorrow. Pics to follow later.

 

[laguna80]

Nearly done. Removing the vanes was by far the easiest part of this experience. Getting to the air pump was ridiculous for me. Bloody knuckles and arms are proof. Anyway, I'm mostly done. I ended up welding the tube to the air cooler because I was scared of braking the bolts coming of the exhaust manifold. It's a s***ty job and only time will tell if it leaks. I'm totally done with everything except that I bought the wrong size plug for the air rails. I have to get a new BVSV 1 as well since the nipples broke off. For now I have it connected to BVSV 2. I will get it started tomorrow and then post up pics of everything. It's going to look very similar to Trapper50cal's because I used his as a guide.

 

[laguna80]

Got everything buttoned up just now. Pics will follow this. I followed trapper50cal's desmog which is an HAC delete desmog. Things that are different on mine. I had to get huge ass bolts to plug the air rail holes because the hardwares stores didn't have those pipe plugs in the right size. I broke the nipples on BVSV 1 so I'm using BVSV2 for now until I get a replacement. The truck runs like s***, but I have a feeling that there are major exhaust leaks. I can't even get the damn thing to idle. Well, here are the pictures. Let me know if you see something totally jacked. Tubing is all silicone variety from McMaster-Carr.

 

[laguna80]

I'll post up pictures with connect the dots to show where the lines lead later on. I wanna go work on the truck more.
UPDATE: Found that it runs like crap with the choke on, but runs fine when the choke is pushed in. I guess the choke makes it run way too rich which causes the engine to die.

 

[Willman]

Well after hours and hours of reading....Finished up my desmog.

Big thanks to Jim C. for all this hard work on my carb./dizzy.

How do i look?

She runs good....I do have a weird vibration at idle sometimes.....Timing off causing that? Hit the gas and it goes away.....

Few questions....

1. Which green wire gets grounded? Pictures for me would help.
2. What do i need to set the timing at? (7-8??)

Thanks

 

[laguna80]

1: I think the wire to ground is part of the fuel decel cut circuit. I don't know for sure though, probably wrong about that. This thread might help, although there's no pics. https://forum.ih8mud.com/60-series-wagons/139820-if-you-havent-done-green-wire-mod.html
This post may be what you need to do. https://forum.ih8mud.com/60-series-wagons/188643-my-desmog-thread-4.html#post2979504
2: Timing should be at 7* before top dead center.

As far as timing goes, I've got myself a timing light and tried to check timing yesterday. How the hell do you all see the BB on the flywheel when it's spinning that fast?

 

[laguna80]

So, here's the color coordinated version of my desmog. The lines can be traced although I couldn't get pictures of the back of the carb. Bronson is running much smoother now and I got rid of the overheating issues by making a block off plate for the tube coming off the manifold that went to the egr cooler. Plus adding coolant and water helped.

 

[Willman]

TTT for some smog looky looky

 

[FJ40Jim]

Well after hours and hours of reading....Finished up my desmog.

Big thanks to Jim C. for all this hard work on my carb./dizzy.

How do i look?

She runs good....I do have a weird vibration at idle sometimes.....Timing off causing that? Hit the gas and it goes away.....

Few questions....

1. Which green wire gets grounded? Pictures for me would help.
2. What do i need to set the timing at? (7-8??)

Thanks

Nic,
you're welcome.

Timing would have to be way off to cause a vibration at idle. It's prolly the normal fuel distribution misfire. It's the nature of a single carb on a long engine.

Are you grounding the idle circuit, or are you keeping the decel fuel cut system?
If the decel fuel cut is to be removed, then permanently ground the ground wire for the carb. Dunno colors, I always check w/ the VOM to be sure. Turn the key on, probe the vehicle connector to the carb. one wire will show +12V, the other will show zero. The ground (zero V) wire from the carb needs to be grounded. Snip the wire, install a ring terminal and screw it to body.

Start with the timing at 7* (at the BB). Drive it and listen for spark knock, especially in the critical 1800-2200RPm range. If it runs well, advance several degrees, test drive again. If knock is heard, or tork decreases, set timing back. If no knock is heard, then advance again. Keep advancing until knock is heard or tork decreases, then back off several degrees.