cascades

Hello!
First time poster and new Toyota owner here, please be gentle.I have wrenched on fuel injected volvo 240's for years, this is my first time owning a carbureted engine. I purchased a 1979 4x4 short bed truck about a month ago and put 350 miles on it to date. It's not a show truck! Bought it for recreation and tinkering. Started fine, idled fine, ran fine, stopped fine. Had no problem going 75 on the highway.
Here are the specs that I know so far:
-22r engine (1985)
-weber 32/36
-1985 4 runner transmission
-10w-30 synthetic
-desmogged
-4x4 with 3" lift

A couple of weeks ago I took it out to the mountains. Drove about 40 miles of gravel road. I had a little trouble getting it started after lunch, but attributed that to the fact that I was at about 5500ft elevation. Once running all was fine... While driving home I started getting hesitation if I let off the accelerator at highway speed. It got progressively worse and when I came to a stop I could not keep an idle. Engine stalled and bucked wildly and could barely limp out of the intersection to the side of the road. I let it cool down, did a visual inspection and found no loose parts, hoses, etc and didn't have tools with me so got a tow home. It would start right up but would rough idle and die in about 5 seconds. Fuel tank was 3/4 full with 96 as recommended by the PO.

The vacuum advance was not holding vacuum on the port nearest the distributor (capped off), so replaced that with a new part from LCE. Also have replaced the plugs-ngk, wires-ngk, cap and rotor, air filter-k&n, fuel filter. I have the timing set to 8* (tried everything between 5* and 12*). Idle is around 1000. I reset the carb to weber baseline specs. The truck starts right up and idles ok (more fine tuning needed for sure). However, when I apply throttle it stumbles, hesitates and dies. If in gear, it will die before I can fully release the clutch. The idle mixture screw is over 3 turns out, so according to document the idle jet is too lean. I've got a jet kit, carb rebuild kit and fuel regulator on the way. I could not find any vacuum leaks around the carb or intake manifold.

Has anyone else had this experience? Other suggestions to try? Would a lean idle jet cause these symptoms? Or am I looking at something else as well? Thanks!

L5wolvesf

First, you're kind of throwing parts at it before establishing the cause of the problem.

How did the plugs that you took out look? PICS would help
Does it not have a fuel pressure reg on it now?
What does the fuel bowl look like and while it is open what does the needle and seat look like?
Also, while it is open chart all of the jets in there now - I seen here a couple situations where the jet kit doesn't cover what you might need.

cascades

The plugs looked normal, worn, but fine. There was some corrosion on the cap and wires. The truck had seen little use before I picked it up. Parts were planned to be replaced as an overall tuneup.

No fuel pressure regulator installed.

I'll open the carb and have a look at what is installed.

Thanks.

Lons81

iTrader: (2)

You might check the condition of the accelerator pump, after a long time setting, it might have dried out and cracked

cascades

Thanks Lons81. There should be a new diaphragm included in the rebuild kit. Will definitely check it out.

Punjab

Does it have a cat in the exhaust? Is it clogged?

Can you look down into the barrels of your carb and check these little brass tubes that run across the barrel?
This is an obscure possibility but something which had given me a lot of headache before I finally figured it out. I was experiencing relatively normal operation until I would press the pedal down and open the second, 36mm barrel on my 32/36. It would lean out and nearly die. Certainly buck and was just horrible performance.
I tried every jet combination I had until I looked down one day and thought that can't be right. That brass tube comes loose in mine sometimes and the open side with the cutout, being lighter, rolls up and fuel doesn't spray down into the barrel as it should.

Like I said, it's not the most likely possibility but this drove me nuts until I figured it out. There are a thousand different things that can go wrong so hopefully you can figure it out. Hopefully I could be of some help.

cascades

Thanks Punjab. No cat installed. The picture is helpful, I'll check that out tonight when I get home.

13Swords

I'd definitely recommend the fuel pressure regulator. Webers are notorious for not liking anything more than 3 PSI. Your stock pump puts out 5 to 8 PSI. Your little gravel road excursion may have knocked loose the brass tube as Punjab suggested, worth a look. You do have a fuel return line from the carb to the tank hooked up right?

Base timing for 22R should be 5 BTDC, idle should be 700-800 (even with the Weber). The 1000 idle makes me suspect the PO wound in the idle speed to make up for something. Either too small of an idle jet (as you already suspect) or a blocked idle circuit he didn't want to bother with, as it was running. The Weber setup instructions says something about this (http://www.carburetion.com/Weber/adjust.htm). Mixture screw more than 2 turns out you need a bigger primary idle jet. I agree you should map the jets you have first. Your forthcoming rebuild should clear any idle circuit problems with a decent clean out.

96 octane gas? In a 22R? Whatever for? Tuned right it should be fine with anything from 10% ethanol blend 87 to 89/90 octane midgrade. 96 is just too slow burning & is gonna give you major carbon deposits IMO. I've seen 22RET's (fuel injected & turbo'ed) with up to 12 pounds boost run fine on 89 octane.

I'm sure you're gonna get the problem figured out. And welcome to Yotatech BTW!

cascades

Thanks 13Swords, got the fuel regulator installed today. Sitting at 3lbs. No other changes and no change in performance.

Question for you (and group). The PO had the fuel return line hooked up to the carb. I have temporarily disconnected and plugged the line coming out of the pump. I was unable to locate the return port on the tank? Is it near the out port? Don't have a good visual in there, just going by feel.

13Swords

I can only speak to the fuel line locations on my '78, but I would assume they are likely in the same places (if not similar) on the '79. Here is a pic of my return line:



1978 Fuel Return Line

It's the green colored steel hardline to the left in the pic. The steel hardline comes up from below and is on top of the passenger side fender. My truck is de-smogged as well, but I still have the stock Aisin carb & my return line hooked up from the carb to the charcoal canister (the stock carb de-smogged works better this way, prevents vapor lock, I had a problem with that until I put the canister back in). Originally (stock) this hardline (on the fender) functioned as a vapor line from the tank, so the charcoal canister could "catch" the tank vapors. The Aisin carb only vents vapor from the return port to the canister. My understanding is that the Weber actually returns liquid fuel. Most people who de-smog & go with the Weber pull out the charcoal canister & hook up their rubber fuel return line from the Weber carb to this hardline with no problems. This gives you liquid fuel circulation & also helps prevent vapor lock. As long as your gas cap vent valve is working you shouldn't have any problems with it.

Hmmm, now I'm wondering about your gas cap, & whether or not the valve is working. Always something. Would be cheap enough to replace with a new one & rule that out.
https://www.rockauto.com/en/catalog/...+tank+cap,5900

I couldn't get a decent pic of it, but my fuel feed hardline runs along the frame rail & then kicks up vertically below the carb location.

Another thought. This is a '79 truck, but has a 22R in it? The stock motor for a "79 should be a 20R. The 22R didn't appear in pickups until 1981. This brings up several questions. "79 was (supposedly) the last year for the in-tank electric fuel pump (they used this from '75 to '79, but I've heard of some '80s having it). I'm wondering just what you've got in that tank & whether it's original to the truck or not. It's obvious that someone in the past installed a newer than stock engine, which has the mechanical fuel pump on the head. Did they disconnect the electrics from the old fuel pump, but leave the old pump in the tank? If so you might have a fuel restriction. Those electric pumps have a filter sock on them that can clog up over time. Plus even with the electric pump disconnected it might be hard to draw through a "dead" electric pump. If they replaced the tank & pickup "stem" with an '80 or later stem you have no problems, but I know how people "half-butt" stuff, & you never know what PO's have done to it before. They may not have updated to the later tank & stem when they did the engine swap, not wanting to spend more $ or do extra work, or both. Always something to consider in older vehicles; you never know what's been modded, torn out, bypassed, etc. but I'm sure you know that having worked on those older Volvos.

Of course the only way to know for sure is to drop the tank & see.

cascades

I'll grab another fuel cap-easy cheap part to rule that out. I'll have to go out and trace out the fuel lines again. I could only locate one line coming up along the passenger fender and feeds directly into the fuel filter-pump-carb. The charcoal cannister is still there, but does not appear to have been connected to anything for a long time.

You are correct about the electric fuel pump, it is still installed in the tank.....I assume the electronics have been disconnected but will verify. A big part of the adventure here is trying to determine exactly what has been done to this truck. I am the third owner, but it seems most things have been altered and modified in the last 40 years.

Side note about Volvo's, I've got an 88 240 wagon that I bought 10 years ago. Was non running at the time and is now my daily driver with over 350,000 miles on the original engine. Completely unmolested. Most of the parts said made in West Germany on them!

cascades

Ok, had a better look at the fuel lines in the daylight. Thanks 13Swords for the image, that was helpful. Tried a new fuel cap-no change-so can rule that out.

Currently the return line is connected the charcoal canister. See photo. If I am understanding correctly, I can connect the return line from the pump to the hard return line on the fender? See photo.



Current charcoal canister and return line connection.



Proposed return line connection (red line)

cascades

Started the rebuild on the carb. Found a couple pieces of rtv gasket maker in the float chamber along with some other miscellaneous crud. Also, the seat on the bottom of the needle valve was gone. Hopefully a good thorough cleaning and replacing the needle valve will help!

L5wolvesf

From the look of the carb you may have been pushing fuel past the top gasket. 2.5 is best recommended setting for 32/36 fuel psi.

13Swords

I'll try to take it in order of your posts; you've been a busy beaver!

Cheap piece of mind (fuel cap) is always a good thing.

No problem on the pic & it's good to see yours, makes it easier on my end. Correct, that is the vapor line from the fuel tank currently shown as connected to your canister (looks like the riginal hose & clamps too!) You can connect the return line from the pump to that hardline but a word of caution first. Since that line has been a vapor line for 40 years it may have a goodly amount of "schmootz" & stuff in it. There has likely never been any liquid fuel in it, which would have helped keep it clean. If you have a way to flush it out first thoroughly with some kind of solvent & compressed air I'd recommend you do that 1st. When I tried to flush mine out it was very brown looking stuff that you're probably not going to want washed back into your tank.

Once you get that done & the return line connected to that hardline, you can take out the canister, as it's doing nothing for you now. The proposed hose routing you have shown looks good to me.

Nice to know I was right about the pump still being in the tank; thanks for that. As long as it's not blocked or crudded up you should be able to pull through it, but ya never know. Guess you might need to check the pump flow while you have everything carb related off. Originally on the trucks with electric fuel pump, there was a fuel pump resistor on a steel mounting plate, mounted on the passenger fender well, in the engine compartment. I do not see it on your pics so it may have been removed. Here's a pic of mine for reference:



Resistor @ bottom of pic, with 2 white wires into a single black, with green connectors. It's just rearward of the battery.

I get what you're saying about the "mechanical archaeology" of old vehicles, trying to find out what's been done. Someone I know calls it "fixing other people's bad repairs." Also, hard to beat that Cold War West German iron. Nice job on getting a non-runner to be a daily asset again!

RTV gasket maker on a carb. I will never understand what some people are thinking (or non-thinking, as the case may be). Agreed, a clean carb & a working needle always helps.

Agree with L5wolvesf, I've also heard plenty that 2.5 pounds is perfect for the Weber, & that gas may have been pushing past the upper gasket. Mebbe because the missing needle seat was allowing it to flood some or more? Would also explain the idle being wound up to 1000 to make use of the extra gas flowing into the carb that wasn't supposed to be there.

Nice work so far boss, keep at it.

cascades

Okay got the carb all cleaned out. I mapped all the jets:
Primary idle - 60
Secondary idle - 50
Primary air corrector - 170
Secondary air corrector - 180
Primary main - 140
Secondary main - 150
Primary emulsion tube - F50
Secondary emulsion tube - F50
Pump discharge - 50

L5wolvesf

OK, those look pretty much like out of the box/never been tuned jet numbers.
I don't recall if I asked but is your engine modified in any way (cam, headers, etc)?
Also, what is your elevation where you normally drive?

cascades

To my knowledge the engine is stock (22R).
I live near sea level, however I take frequent trips to the mountains, so could be up as high as 6000'.
I got everything put back together and tuned the carb per weber instructions. Timing is at 5*, fuel pressure at 2.5 and idle is still sitting around 1000. Any less and it gets rough. Seems to be running fine otherwise, was able to take it out for a 20 minute test drive.

Thommo Thompson

well everythign was fine and suddenly it wasnt.
So somethign obviously happened in the carb.
Id say a piece of gunk went into one of the jets, or jsut the opposite, that float needle suddenly let go, adn thats probabyl what u saw in the float bowl, and its probabyl now also lodged in the fuel circuits.
Im certian a clean out and rebuild will get u running sweet again..
Carbys are better than EFI, because computers cannot be visully checked, carbies can!

13Swords

Those numbers do look pretty stock, altho the Air Correction Jet sizes look a little bigger than stock, & also backwards.

Weber stock jet sizes: https://www.racetep.com/webercarbjet.html

Looks like the primary Air Correction Jet should be bigger than the secondary on all 32/36's, according that chart. Don't know if that makes any difference. Could someone have swapped them around previously? Where is the idle mixture now, how many turns out?