Hello, okay so im pretty new to the toyota world, i have a 1987 pickup 4x4, i think its the sas?? anywho, after a theft and blown motor its got a fresh blueprinted 22r with rv cam, header, and webber carb. it has new plugs, wires, cap, rotor, clutch and flywheel. the timing is advanced 13 to 14 degrees. the truck runs between 130 and 160 "installed a fail safe thermo stat" my issue is after about 15 to 20 mins of driving and cruising the truck will kinda spudder and if i step on it the truck hesitates, now after coming to a complete stop the truck idles high but if i bump the gas pedal it drops.

so my question is would these problems be caused by the carb, timing or something else? and is the running temp good? shouldnt it be atleast 180 to 190?

 

the temp should be regulated by the thermostat, when was the last time you had the carb tuned? Is it a stock carb? And a SAS is a solid axle swap, so if you have a solid axle under the front and its a 87 then yes it was sas'ed

 

well then no its not a sas... thank you now i know what that means.. lol i bought the truck with the webber. i have not had the carb tuned nor do i know how to.

 

Could be the fuel filter needs changed.

The throttle linkage do you lube it from time to time?? Might be causing the high idle.

 

Temp runs between 130-160?
Did you look ON the thermostat to see what the opening point is supposed to be before you installed it?
Might be a reach but it could be that the thermostat has too low of an opening point or it's already stuck open (it happens) and the low temperature is causing a rich mixture. That's assuming the carb was tuned for the warmer factory thermostat temps.
My carbed V8 Chev's really don't like to be ran below 160 degrees and perform much better on the street with a 180 degree thermostat.



What gauge are you reading that temperature off of? A stock gauge, an aftermarket electric, or aftermarket mechanical?
In the case of an electric gauge you could be reading an incorrect temperature because the sending unit isn't correct for the gauge.

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okay so i found out that my fail safe thermostat was a 160 degree stat, i bought a 180 stat today. we shall see how that goes.

iv also learned that my timing is about 2 degree advanced from what it should be.

i was recomended a good carb place as well that i will check out tomorrow.

so on this note i will keep everyone of you up to date. but as for now i havent been able to change or do anything to the truck yet.

ODIN i am using both the stock electric gauge and an aftermarket mechanical gauge. both stay on a low temp.

 

Yeah, this sounds more like a carb problem. As far as carbs, I don't know too much about these things, I only rebuilt one off an old ford.

There's a butterfly valve at the top of the carb, and it controls your air flow. So when it's cold, the valve will be mostly closed, for more fuel to air ratio for cold starting, then as the motor warms up, when you tap the gas pedal the butterfly valve will open up more. And it will only do this if it's hot enough, on the old carbs it would be controlled with one of those spiral things that expand when heated up, like the thing on the engine fan clutch.

On the new ones, these are usually automatically controlled by vacuum or something (I think), so it will automatically open up the valve when it gets hot.

So it could be something like that, or like Wyoming9 said. There could be something wrong with the throttle. There's a power valve on carbs, it's basically like a vacuum diaphragm. So when you press the gas pedal, it pushes on this power valve/diaphragm that lets more gas flow throw the carb. Maybe the diaphragm is damaged or the linkage gets stuck.

Anyways, I never have messed around with toyota carbs, so don't take my word on anything. But I would definitely check out that carb place, it could be as simple as tuning it. Just my 2 cents.

 

That's kind of my point.
My thought is that if the coolant is too cold there MIGHT not be enough engine heat to keep the carb out of it's cold start cycle. In my head 160 degrees is likely,.. ok, but when it dips below that it's too cold so it goes back into it's cold start/warm up mode causing a richer mixture. At any rate the temps coming out of the heater usually suck with a 160 degree thermostat.

Out of curiosity I'd try the 180 thermostat before I handed the truck over to a shop. If that ends up being part of the problem then you've just paid somebody good money to do something you could have easily done yourself.

Being 2 degrees advanced is not likely to cause an issue and in fact most of the time helps out the lower rpm torque. The water temp readings sound trustworthy.

 

Initial timing advance is fine unless you're pinging. R engines like 180-190 thermostats. Try out the 180.

Your Weber will need jetting. Especially with a bigger than stock cam. Get a jet kit and follow the Weber tuning guide. This will likely solve your problem.