Hello all,

So I have begun digging into the carb and or idle issues on my '83 SR5. I'll try my best to go through everything I've been through to this point. Also, FWIW I've never owned a carbureted vehicle before, so take'r easy on me.... please?

For one, when I first purchased the truck it was not running great. It would start and drive, but would bog and buck a bit it seemed until I guess it warmed up. Then a day or two after I bought it I took a look at the cat and it was bright red after just a spin around the neighborhood. So I cut the seemingly pretty clogged cat out, and temporarily have a 18" pipe with clamps in its place.

Then the truck began to start and run OK - I guess, for the most part with the exception of a pretty high idle (~2200RPMs). I figured it could use a good tune up. I did the plugs, wires, cap and rotor, fuel filter - all OEM parts. If anything it seems to start a little snappier, but no change in idle. This led me to turn to the carb.

I know that 'normally' after the truck starts you can 'tap' the throttle and the idle should come down. This truck has never done that - the idle stays where it is. (not sure if this is a huge indicator of something to some of you, but figured I'd note it). I figured vacuum leak - but I certainly don't hear it if its a large leak, and spraying carb cleaner on every vacuum hose/T connections that I could see as well as towards/on the carb itself did not lead to any changes in RPMs.

I've screwed with the cold/warm idle/mixture screws. Nothing really makes much of a difference than I can tell aside from the warm idle screw. I've found the video/or responses about the baseline settings of 3.5 turns out on the warm and 2.5 on the mix - didn't seem to really help much.

I should say this is a california truck, so it has all of the smog ˟˟˟˟ on it - which living in Maryland now I'd love to take all of it off sooner or later - but that said I want to endure the pain and suffering that is working on all of this as-is first.

Other things worth noting, I've never seen ANY fuel in the sight glass. Ever. I've put flashlights to it while running/not running and I've never seen anything through that damn thing.

Through extensive searching I've come across the fuel cut solenoid as a potential culprit for idle/carb issues. Well yesterday I got the stones to go out and take mine off. Sure as ˟˟˟˟, when I pulled it out, I was missing an o-ring on the end of it, which I found interesting. Per the FSM I purchased, if that thing is cracked or missing it needs replacement. That said, what size is it?

I have paintball gun rebuild kits laying around that all have o-rings in them with all different kinds of sizes. Yesterday I tried my luck with one. and wouldnt you know it - it ran better than its EVER run. That said, it did it for about 5 minutes and as I was testing it - i heard a afterfire type of pop and then while coasting down the neighborhood hill the truck died and would not start until I towed it back up the hill with my 4runner and about 20 minutes had gone by.

Well today I decided to dig back into it and pulled the solenoid out again, and the o-ring I had tried was no longer in the grooves of the tip of the solenoid. I don't think it was pulled out on solenoid removal. Was this what caused it to die and no longer start at the bottom of the hill? IDK.

So I went to advanced auto and picked up their tan (rated for fuel applications) o-ring pack and tried a few. The smallest one in the bunch seems to fit the solenoid pretty well, however - when attempting to put the solenoid back in the carb it is met with some resistance. I can get it back in, and have. However, for the hell of it - I pulled it out after re-assembly and the friction of the solenoid being removed pulls the o-ring out of the grooves. So I have no idea if when inserted it is even doing what it is supposed to be doing and sitting in the grooves of the solenoid correctly - or if its being pulled out on insertion. I can say that there is still no fuel seen in the sight glass - and I am going to have to take a guess that these issues are related (solenoid o-ring and the no seen fuel in the glass). It drives... better? I think? Definitely seems to be a bit more powerful. Idling around 1.1k which is fine with me.

When I purposely test decelerating it seems to 'bog' a bit? definitely doesn't really "coast" freely if you will. Is this the solenoid working? It's not very quiet - it seems. It very likely has never worked during my ownership so I cant say I know what it should be driving like with a perfectly working carb and cut solenoid.

Also, for what its worth I pulled the emissions control box out and checked the soldering on the board. If there are any cracks on them my eyes couldn't pick them up. It looked OK from what I could tell. I had high hopes that this could be my problem in the first place.

I have NOT had a helping hand to tell me if the solenoid is clicking during key-on to even know if its even still good - again for what its worth. Nor have I probe tested it from the battery, yet.

Is the only way to get the correct o-ring in a carb rebuild kit? This carb was replaced by a PO with a TOY-505 from national carburetors in 2017. While it is an Aisin and presumably an OE quality carb - are there any known issues with this particular carb? Should I try my luck with an actual OE carb that could be had used and then purchase a rebuild kit for it? It seems like OE solenoids can still be had, however not cheaply. (~$250-300). Would that even fit the TOY-505 if I went that route?

I will ALSO note, that I have an LCE street header in the box waiting to be installed. When I cut the cat out, I left the TWC - which looks like it was welded in after the cat. So I dont know where THAT stands in all of this, but I would imagine the temporary pipe i put in pace has all kinds of air being mixed in before exhaust hits that TWC which I dont know what that means for the air/fuel mixture. I don't know if cutting that cat out a day after ownership was what is causing all of this and I learned a lesson in doing so? Or if possibly when I put the LCE headers in and have an exhaust shop finish the rest of the exhaust which I would assume will include the TWC if all my woes will go away(wishful thinking?).

Thank you if you have taken the time to read through this. I very much appreciate it. I know its all over the damn place but I type as ˟˟˟˟ comes to me sometimes.

 

Yah quite the treatise you wrote here and so here's mine! Better too much info then not enough. Before I retired I was a millwright for 40 years or so, the guy who could tell me exactly what his machine was doing before it quit got it fixed faster then the troglodyte that grunted, "machine not run"!

To start all US destination trucks have the idle mixture screw "sealed" with a tamper proof plug...has this been drilled out?

Next don't just start screwing adjustment screws in and out. You indicate you have the FSM, everything you need to know and how to do it is in it; adjust the carburetor as indicated. I get the feeling this truck has sat for a bit or longer. Get a can a carb cleaner a spray it down. Careful it'll remove paint. Wiggle all the linkages, the throttle and choke plates when you're doing this. Sounds like the fast idle cam may be sticking. Vacuum leaks usually cause rough idling. The "computer" on those trucks do nothing to control the basic functions of the engine or carburetor, its purpose is mostly to control the emissions system. It does control the "cold mixture heater", the solenoid you are questioning and possibly the choke heater. However those three functions can be controlled without the "computer". Myself or someone else can explain how to if thats the route you wish to go...you don't need an electronics technicians degree to do it.

O rings...While I don't know want you bought and cant tell you the size (Did you ask at the dealership?) I can tell you this much. There are two "usual" types of O rings, Nitrile (Buna N) and Viton. Briefly as I can Viton is excellent for gasoline but poor for Ethyl alcohol, Nitrile is excellent for Ethyl alcohol but only acceptable for gasoline. Thus if this truck has been sitting around with ethanol gasoline in it some of the O rings could have rotted and/or cracked. Further to that a carburetor that has "dried out" can corrode in short order. By dried out I mean its sat for an extended period of time and the gasoline has evaporated out. The ethyl alcohol part has absorbed water, and as we know oil floats on water...guess whats left on the bottom of the float bowl!

The idle cut solenoid shuts off fuel to the idle circuit when 1) you turn the engine off to prevent run on and 2) when decelerating to prevent cat overheating/backfiring. Your over heated cat seems to point to this.

The truck should idle at about 700-750 RPM. There should be fuel in the sight glass. You may have a bad fuel pump but I suspect its the float not set properly. The choke/fast idle should "kick" down to idle on its own without you touching the gas as well as touching it.

When doing anything more than routine on a carburetor take it off the vehicle and do it on the bench! Some of the little parts invariably will launch themselves into the next galaxy where they will be lost forever. On the bench you have at least a chance of recovery. You could then bench test that solenoid solo, inspect where it seats and have a good look at the choke/fast idle linkages. Its just four nuts and a bit of linkage and well a rats nest of hoses.

All your problems really seem to point to the carburetor...all I can say about National Carburetors is they had no idea there was a Canadian (non-emissions) carburetor and the picture of their TOY-505 is missing the Hot idle compensation valve which only the 83 had...read into that what you wish, plus they wouldn't ship to Canada...guess my money was no good! I got my replacement from "Auto-Line" out of Winnipeg about 5-6 years ago and it runs like a deer! As I said before the Aisin carb is a good unit sized correctly to the engine. I forget what the CFM's is, but its more than enough. Carbs and emission equipment don't play good together simply because there is no "feed back" like EFI has, so the carb doesn't know what the engine is doing. Like Star Treks Mr. Scott said, "the more you overdo the plumbing the easier it is to stuff up the drain"! Just look at the hose routing in your FSM. You either need to re-build that carb or get another rebuild. Do you have the skills and a nice clean place to do this?

It sounds like at some point your going to de-Smog it, just bite the bullet and do it. Why beat yourself up and waste time? A lot of guys replace the stock carb with a Weber 32/36. Be aware there are advantages and dis-advantages of doing this such as custom jetting. You'll need an adapter or a new manifold specifically for the Weber...Offenhuaser makes a "single plane" and "dual plane" ones for the Weber. "Single plane" is like the stock manifold runners, "Dual plane" the runner is split in two horizontally. The former is good all round and for top end power, the later for low end power. They also make them for the stock carb...there is little point getting a single plane Offy manifold for the stock carb. I like the stock carb...Toyota knew what they were doing, it bolts right on and is ready to go, the linkages hook right up etc.If you decide to keep the stock carb, re-plumb as per the "Canadian emissions" diagram and plug the un-used ports on the carb. Believe me it works just fine that way! You may need to fab some block off plates or buy some. LCE makes a bunch of them.

If your putting on headers, or de-smogging pitch the TWC and converter assuming regulations in Maryland allow you to do this. All you need is the header (or manifold) a piece of pipe, the muffler and a tailpipe.

 

Thanks so much for the reply. I think I'm on the right track. Sounding like a hypocrite (as I am about to throw headers on it) I kind of want to keep it some-what OE toyota - including the carb. Primarily due to the originality of the truck as a whole. I think I may look to get a used OE carb and rebuild kit and go to town.

Good to know I can just ditch the TWC. Once I get the headers in, I'll see where the connector pipe supplied by LCE gets me and with any luck - it replaces the section of the exhaust that the cat and TWC took up but I'll cross that bridge hopefully this week if I can find the time to do this.

Cheers.

 

Has anyone found a replacement for that O-ring mentioned initially?? Mine is cracked and I tried different o-rings with no luck to fitment.

87 p/u 22r california model.

Thanks

 

The o-ring is still available thru Toyota. Part # 21655-44101, 8/83-8/88

 

You Sir are a godsend! Thank you!
now I'm having another issue for anyone that can direct me to a proper thread.
87' pickup 22r California. Rebuilt carburetor, new fuel pump and filter. Ran perfect for about 6 months. Now, my fuel bowl won't fill up to the half way mark and going up hill or punching it starves the carb. I replaced the fuel pump again thinking it was faulty but no fix. I filled the carb bowl up with carb cleaner from the inlet and it will run it down back to almost nothing. Idles perfect and drives normal under light loads. The pump is filling a water bottle up pretty quickly. I'm at a loss

Thanks,

 

Did you rebuild the carb? It's been 3 years since I rebuilt my carb but if I remember correctly there was an o-ring in the kit for the fuel-cut solenoid. That o-ring should have been replaced as part of the rebuild. With the other problem you're having I'd be suspect as to what else wasn't done.

 

Good morning,
I took it to a shop to get rebuilt. 🙄
they had a 5 month warranty but I'm out of that now. 👎

 

Replacement o-ring came in and fixed my dieseling after shut-off. (It was bad. Would diesel for about another 7 seconds if I didn't use my clutch)

Took the horn off of the carb and messed with the float adjustment. 9.8mm closed 48mm open. After messing with that for a while, I managed to "unstick" the needle?
not sure exactly what I managed to fix but I left the fuel line connected when pulling the horn off and it shot a nice jet of fuel out the needle. After that it's been running perfect again. Took it for a test drive up hill punching it. That was a scenario where it would starve for fuel and shudder. All is good again!