It just started snowing and getting cold here. Now when I start the truck early in the morning and the temperature is real low outside, the engine runs at high RPM and quick jabs on the accelerator will not bring it down. Only after it warms up a bit will it come down to normal. I can start the truck cold in the middle of the day when it's warmer outside and NEVER have this problem. What's going on?

 

Won't that harm the engine being cold and no oil flowing at first?

 

how high is the idle?
usually it takes less than a few seconds to get oil going... when you have a huge filter like me. what oil are you using?


let the truck sit for about 30sec, its a general rule i use with all cars

 

you have an oil light on your truck, if its off that means you have full oil pressure, when you start it watch, you build oil pressure in like 2 seconds after starting. High idle is normal when the engine is cold.

 

It will run WAY HIGH for about 2 minutes, then suddenly drop to normal.....i'm scared it will blow up. I can't see the truck running that high of an RPM for 5 minutes like the responder said. It runs REALLY high. It runs REALLY high. It runs REALLY high. It runs REALLY high. Did I mention REALLY HIGH? It runs REALLY high. I turn it off thinking I will cause PERMANENT engine damage. Warm weather, no prob.....so weird....

 

do you have a tachometer? running really high can me alot to different people. i take it as its above 5k rpms, thats high..but it is very normal for the truck to idle up when cold outside.. if it stays like that the whole time then you will have a problem..but it going down by itself is normal..

 

Go to YOUR truck. Push the pedal to the floor. Pretend to hold the pedal to the floor for 2 minutes after your truck starts and warms up. ALL the WAY to the floor! Tell me you feel comfortable for 1-2 minutes while your wonerful little 20r rubs her arms and tries to warm up by running full RPM....but not in sunny weather. It is so loud, it REALLY sounds DANGEROUS!!!! It's a $400 truck with an engine that does not smoke and is STRONG. I don't wanna screw it up. Sorry, don't wanna sound like an ass, I just have a strong drivetrain and a crappy body. (my Truck ain't feeling too good either...LOL...)

 

i still say get a tach and see what its idling at..that way you know for a fact what its doing..if anything you can probly adjust the cold idle setting on the carb..

 

Where is this located on the stock carb?

 

These instructions are from my Chilton's manuel...

1975-79 20R Engine
Fast Idle Adjustment - Carburetor on truck
1. Start the engine and allow to reach normal operating temperature.
2. Stop engine and disconnect the vacuum hose from the EGR valve. Connect a tachometer to the engine as previously outlined.
3. Open the throttle valve slightly and close the choke plate, which will set the fast idle cam.
4. Disconnect the vacuum hose(s) from the distributor vacuum unit. Plug the vacuum hose end(s).
5. Without touching the accelerator pedal, start the engine and read the tachometer. If necessary, adjust the fast idle speed to 2400 rpm by turning the fast idle screw.
6. Reconnect the vacuum hoses to both the EGR valve and the distributor vacuum unit. Disconnect the tachometer from the engine.

Now the only other thing i find in the manual is this--

Automatic Choke Inspection and Adjustment

Steps 1-4 must be performed with the engine cold and turned OFF.
1. Remove the air cleaner lid.
2. Depress the accelerator pedal. The choke plate should close. If the choke plate closes, proceed to Step 5.
3. If the choke plate does not close, loosen the three screws around the thermostat case. Do Not loosen the center housing screw, coolant leakage will occur.
4. Rotate the case just until the choke plate closes and tighten the case screws.
5. Start the engine and allow it to reach normal operating temperature. If the choke plate opens fully, the choke adjustment is correct. if it does not, loosen the three case screws and rotate the case until the choke is fully open. Tighten the case screws.

This is word for word from the Chilton's Manuel. So again i want to recommend you get a tachometer so you can see just what the idle is at when its warming up. Without knowing that then, there is no point in messing with the truck. As you can also see the automatic choke opens the barrels fully to warm up. Well hope this helps.

 

Is this your first carbed toyota?

In cold weather, the carb has a "fast idle cam" that opens the throttle blades up a bit, while keeping the choke closed. This is so that the engine warms up quickly in the winter. From the factory, they're set to idle @ between 2k and 2500 rpms. Does this sound really high? Yes. IS it really high? No. Once the engine warms up a bit (one needle width past the lower bar on my truck) one quick blip of the pedal drops the carb off the fast idle cam and back to the normal 800 rpms or so.

Again, buy a tach.... anything above 2350 rpms in these trucks sounds like it's gonna blow up. Rest assured, it's not. You can pick up a sunpro tach for cheap from your local parts store. 4 wires to connect and it's done.