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First 22R, bought a month ago. 87 Pickup - 4x4 non-Cali / carbed. - 5 spd. 175 K original miles.
Ran great when I bought it, still starts and idles fine, but feels like it's under load when driving now.
Had a recent tune-up prior to purchase and I haven't done much to it. Replaced the battery just before this new issue developed. As I was doing that, I noticed a small vac line disconnected to the left of the air cleaner. I reconnected it.
Prior to this event, it did, ( and still does ), backfire occasionally when shifting into 4th at high RPMs. Other than that it ran like a scalded dog.
There's no noticeable chain clatter.
Doesn't run hot, no fluid leaks.
It's not mis-firing or staggering, just feels bogged down.
My best description of the issue is that it feels like it's low on oil, though it's not and the oil is pretty clean having just been changed in the last year.
( the truck has spent the last 10 years as a light use farm truck, hasn't seen the road much at all in that time. )
Converter has been removed, running a straight pipe into a Cherry Bomb. ( Damn it's loud ! )
There is a faint odor of gas, but I can't detect any at the exhaust. Maybe running rich ?
I don't want to start throwing $$ at it before I've asked the experts for advice... thanks for your consideration !
You tryed reverting to the prior vacuum configuration yet?
Went over the electrical connection?
Change your oil! Oil has a lifespan of a few thousand miles OR a couple of months.
Bad fuel, clogged jets and filter (pretty common for low use farm vehicles)
Just because a prior owner says it had a tune up is no reason for you not to double check things are in spec fresh and clean (recent for them might of been years ago, and you don't know for certain what was done or done improperly)
If it's been a farm truck then it's been around a lot of dirt. Post up a pic of the carb also post your location in the profile.
Thanks L5wolvesf. I'll try to get a pic of the carb tomorrow. It's definitely seen some dirt / dust. The filter does look pretty fresh, though.
The blower fan was also completely packed with a mouse nest... and the air ducts must still be ! Gonna try to blow it out tomorrow, as well.
You tryed reverting to the prior vacuum configuration yet?
Went over the electrical connection?
Change your oil! Oil has a lifespan of a few thousand miles OR a couple of months.
Bad fuel, clogged jets and filter (pretty common for low use farm vehicles)
Just because a prior owner says it had a tune up is no reason for you not to double check things are in spec fresh and clean (recent for them might of been years ago, and you don't know for certain what was done or done improperly)
Thanks Co_94. I haven't pulled that vacuum line, but I will try it disconnected, since that's about all I've changed !
I cleaned up the ground to frame connection when I changed the battery, most of the electrical seems good, although there must be a ground issue with the license plate lights. I replaced the bulbs but they're still not working. Gonna try cleaning up the housing ring, I assume that's how they are intended to ground and they are way rusty.
I did pop the dist. cap and cleaned up the rotor a lil, ( after this issue started ), but it does look pretty new, as is the air filter. Haven't pulled a plug yet, but I guess that's worth doing, too. I have a decent set of performance plug wires, thought I might swap those out.
I do know the previous owner, well. But, indeed, he wasn't specific on exactly how ' recent ' the tune-up was. I'll give him a call and ask.
All good suggestions. Thx.
Hi guys, sorry for my delayed reply... a late summer cold turned into pneumonia and I'm just now back on my feet !
Here's a couple of pics of the carb, as requested, including the float window. ( level seems normal ).
What I've done, so far...
Full tune up ; plugs ( NGK BPR5EY - Gapped at .32 )
New dist cap and rotor, Beck / Arnley high performance plug wires, Fram air filter, Duralast fuel filter ( I had high hopes that this was the issue ! ).
I still need a PCV valve, but pulled the fairly new one on it and it rattles / seems to be fine.
I also changed the oil and filter, ran a bottle of HEAT through the tank with 10 gals of high test.
I did try disconnecting the vacuum line that I had found broken, ( no change ), but then replaced it completely as I discovered it was broken in another place.
None of this effected any noticeable change.
To recap the issue ;
Truck starts and idles fine ( maybe a lil low idle but doesn't miss or stumble ).
Plenty of torque in 1st, but in 2nd and 3rd. gear it feels bogged down on acceleration. ( Same in 4th / 5th at highway speeds if I have to climb any grade.) Shakes and seems restricted, almost like it's choked.
Which MAY be the problem... I noticed that regardless of engine temp, the secondary throttle valve / flap stays almost closed. And, when I bump the throttle up by hand, it actually closes more. Seems like it should open more at higher RPM ? ( been many years since I've had a carb ! )
Thanks again for any help.
If you found a couple bad vac lines you likely have more. Also, it looks like there are a couple plugged lines on the left side of the pic - are they?
The pic shows one side of the choke notches but not the other - is the choke aligned to the center or??
Like I mentioned earlier, DIRT, DIRT, and . . . yes you guessed it DIRT.
If the vac lines don't fix or improve how it runs you may have a carb rebuild in your future. Before that you could do a cheapo "rebuild in a can" carb cleaner spray down. If I were you I would wear a mask when spraying carb cleaner to avoid a relapse. But, me kinda likes the smell of carb cleaner in the morning.
FWIW, the Aisain carb looks fairly easy to rebuild, I have one with a kit sitting in my shop awaiting my attention.
If you found a couple bad vac lines you likely have more. Also, it looks like there are a couple plugged lines on the left side of the pic - are they?
The pic shows one side of the choke notches but not the other - is the choke aligned to the center or??
Like I mentioned earlier, DIRT, DIRT, and . . . yes you guessed it DIRT.
If the vac lines don't fix or improve how it runs you may have a carb rebuild in your future. Before that you could do a cheapo "rebuild in a can" carb cleaner spray down. If I were you I would wear a mask when spraying carb cleaner to avoid a relapse. But, me kinda likes the smell of carb cleaner in the morning.
FWIW, the Aisain carb looks fairly easy to rebuild, I have one with a kit sitting in my shop awaiting my attention.
Thanks L5.
There are 3 vac lines on the left side of the carb that are capped off. Looks like it almost came that way...and, I don't see where they would have run to. Maybe another application for this same carb ?
As far as the choke, there are alignment lines on the inside plastic cylinder, but I can't see any lines on the housing ! Although it does appear to be lined up in the center of the housing.
Should that throttle plate be opening more ? Should I try to wire it fully open, just to see if it makes a difference ?
I will try some carb cleaner tomorrow...and I'll also use it to spray around to look / listen for more vac leaks. Part of the issue is that the first Y pipe off the exhaust manifold is cracked, so it's very loud, Couldn't really hear a hiss if there was a hole the size of quarter ! lol
But some spray may reveal one.
So, I'll get back to you after some clean-up and closer exam of more vac lines.
Thanks L5.
There are 3 vac lines on the left side of the carb that are capped off. Looks like it almost came that way...and, I don't see where they would have run to. Maybe another application for this same carb ?
As far as the choke, there are alignment lines on the inside plastic cylinder, but I can't see any lines on the housing ! Although it does appear to be lined up in the center of the housing.
Should that throttle plate be opening more ? Should I try to wire it fully open, just to see if it makes a difference ?
I will try some carb cleaner tomorrow...and I'll also use it to spray around to look / listen for more vac leaks. Part of the issue is that the first Y pipe off the exhaust manifold is cracked, so it's very loud, Couldn't really hear a hiss if there was a hole the size of quarter ! lol
But some spray may reveal one.
So, I'll get back to you after some clean-up and closer exam of more vac lines.
The vac lines are likely 30 years old just replace them - they will likely crumble and fall of easily. That will eliminate the vac thing and cheaply.
Re the 3 plugged vac lines - has the truck been desmogged? Is the charcoal canister there? A pic of the pass side of the engine bay would be good.
To TEMPORARILY stop the exhaust noise do the tin can thing so you can diagnose better.
The vac lines are likely 30 years old just replace them - they will likely crumble and fall of easily. That will eliminate the vac thing and cheaply.
Re the 3 plugged vac lines - has the truck been desmogged? Is the charcoal canister there? A pic of the pass side of the engine bay would be good.
To TEMPORARILY stop the exhaust noise do the tin can thing so you can diagnose better.
Yeah, sounds like a good idea to just replace those lines.
The charcoal can is still there, I'll post a pic some time tomorrow.
I'll see what I can do with that exhaust, as well. I have a welder, may just try to weld that crack...have to do it off the truck though, because of the crack's location. Removing it may take some doing, though ! More to follow. Thx
Those three plugged vacuum ports on the carburetor are for the optional High Altitude Compensation (HAC) system.
If the vehicle was not equipped with the High Altitude Compensation system, Toyota just plugged the ports with the vacuum caps from the factory, as you see on your carburetor.
My carburetor is the same way as I do not have the High Altitude Compensation system either.
Check the vacuum caps for cracks, as they are probably just as old as your vacuum lines.
Those three plugged vacuum ports on the carburetor are for the optional High Altitude Compensation (HAC) system.
If the vehicle was not equipped with the High Altitude Compensation system, Toyota just plugged the ports with the vacuum caps from the factory, as you see on your carburetor.
My carburetor is the same way as I do not have the High Altitude Compensation system either.
Check the vacuum caps for cracks, as they are probably just as old as your vacuum lines.
Thanks old87. I suspected something of the sort.
I cleaned the carb., twice ! No real change in driveability. It does seem to idle just a lil higher.
I did do a spray check for another vacuum leak, but nothing was evident.
I'm going to replace the lines, anyway, but I had to order the new vac hose, none of the parts places near me had the smaller line.
I'll have to look again for those caps...
The secondary throttle barrel is a Variable Venturi design. When you look down the throat of the secondary barrel, you will not see a venturi like the primary barrel. That choke or valve plate is actually called an "Air Valve" that will initially close to create vacuum for the Secondary Main Nozzle. Any tampering with it, like tying it open will create issues in the Secondary Fuel Circuit. The carburetor will mechanically regulate the amount the Air Valve is open automatically.
The secondary throttle barrel is a Variable Venturi design. When you look down the throat of the secondary barrel, you will not see a venturi like the primary barrel. That choke or valve plate is actually called an "Air Valve" that will initially close to create vacuum for the Secondary Main Nozzle. Any tampering with it, like tying it open will create issues in the Secondary Fuel Circuit. The carburetor will mechanically regulate the amount the Air Valve is open automatically.
Excellent info, slo-mo ! Thank you !
I did watch a couple of vids that showed the function of that " air valve " and it was performing just like mine...so, I left it alone !
Not to be the bad guy, but in 1991, the original rings where completely toast. My mom had lugged it daily, full throttle in 5th up hills. At 60mph. On 31", no regear.
Edit. If you put a timing like on it and its all over the place it's possible the crank pulley key could have slipped a bit. I think thats what its called.
Last edited by thefishguy77; 11-05-2018 at 03:44 PM.
Hey guys, finally, an update ! Turns out, it was, in fact, DIRT !
I was forced to keep driving it occasionally and on one trash haul, something just gave...started running like a scalded dog again !
All I can assume is that it blew out whatever had been clogging it !
But, now I have a cooling issue ! Ugh.
Making a new post for it, now.
Thanks for everyone's help.
09-02-2018, 07:07 AM
