chucknash

I've got a 1986 toyota p/u extended cab 4x4 with the 22R engine, with stock carb. Had it for a few years now and I have started to experience problems starting: (pumping gas pedal 10+ times to get engine to start) and misfire/rough idle when warming up. The acceleration when driving cold is very rough and backfires multiple times, however once the engine has reached running temp. it runs just fine. Gas mileage has significantly dropped as well, can easily say its running rich like most yotas do. I have fresh plugs in, good wires, cap, rotor, fuel pump, fuel filter. I have checked many threads on this issue, many people suggested checking the AAP and Vacuum hoses. I have recently done that and have had no luck. I have taken off the air filter cover and checked to see if choke was working, and it appears to do so. Anyone experience this same issue? Any ideas what else to check? Anyone have links to a thread I might have missed with this same issue? I have looked quite a bit on these threads, still have had no luck. Thanks for your help!

SoCal4Running

Don't check vacuum hoses, replace them no matter how good they look.
If there are any metal lines that transfer the vacuum around like on the RE blow them out with shop air also

slow-mo

First check the fuel level in the carburetor bowl via the sight glass. The fuel level needs to be in the middle of the sight glass.


Do you have a high idle (2500-3000 rpms) when the engine is first started?


Just to confirm, how did you test the AAP?


Just to confirm, how did you test the functionality of the choke?

chucknash

Should i check the float level when the engine is running/off/cold/warm? I checked the AAP by replacing it. The old diaphragm was not torn or damaged and there was no fuel coming out of the line when i pulled it off. When i started my truck cold, i watched my choke slowly open as the truck warmed up so it appeared to be working properly.

stock87

Check the vacuum advance diaphragm on the distributor as well, both chambers if it has the dual. I know when it went bad on my truck, it wouldn't fast idle no matter how well everything else worked, since it couldn't adjust the timing. Extremely common for them to be blown after this amount of time.

slow-mo

Check it just before you start the truck after it has been sitting. The fuel level is supposed to be in the middle of the sight glass. You may have to shake the truck or press the front end up and down to see if fuel moves around in the sight glass.

If the fuel is not visible, then what happens is that the engine needs to turn over to operate the mechanical fuel pump to fill gas back into the carburetor bowl first before any pumping of the gas pedal does anything.

OK, I was just checking. However, you still may have problems with the coolant controlled vacuum switch valve (VSV) for the AAP. If the VSV is not working properly, then you may not have any vacuum going to that AAP.

From your description of the choke, it seems to be working correctly.