1FZ-F Carbureted behaviour after starting

[oneOf8billion]

Hey everyone,
does anyone here have experience with the carbureted 1FZ-F engine? I have a 80series with this engine, but it was also used in the 70series so I also post here.

I have a few questions about the starting behavior and would like to compare whether everything with mine is still “normal.”

When the engine is cold and I start it and press the accelerator pedal quickly, it stumbles and almost stalls. This behavior disappears after a few minutes, and then it runs perfectly. It only happens with a quick throttle inputs right after startup. The behavior also becomes more pronounced when the weather is colder.


Thanks and Greetings,
Björn

 

[LDowney]

My bride's FZJ70 also has a carbureted 1FZ and is similarly cold blooded in that it needs a some warm-up time before moving out. IF I am in a rush, it has the dial throttle advance on the dash and, with a couple turns of the knob, the idle is advanced just enough to avoid stumbling behavior.

 

[DrRock]

Hey everyone,
does anyone here have experience with the carbureted 1FZ-F engine? I have a 80series with this engine, but it was also used in the 70series so I also post here.

I have a few questions about the starting behavior and would like to compare whether everything with mine is still “normal.”

When the engine is cold and I start it and press the accelerator pedal quickly, it stumbles and almost stalls. This behavior disappears after a few minutes, and then it runs perfectly. It only happens with a quick throttle inputs right after startup. The behavior also becomes more pronounced when the weather is colder.


Thanks and Greetings,
Björn

My 1FZ-F has the same characteristic and I consider this completely normal. Anything below 10C and my starting routine consists of two pumps of the throttle, then start the engine and let it warm up for ~1min prior to driving off. Colder weather requires more warm up time

 

[WarDamnEagle]

My FZJ75 is the same. If I am in a hurry I have to keep the rpms a little high to get it going. Mine lives in a garage so once I am backed out and moving forward it’s normally fine.

 

[ranchero7]

Mine sounds similar. I was surprised at how easy it starts up in cold weather. But I have to give it a few minutes before it drives without hesitation.

 

[javelinadave]

It’s the electric choke. It needs to warm up for your engine to breathe fully.

 

[oneOf8billion]

Ok, thanks folk that sounds normal then.

I was worried because the carburetor has a auxiliary acceleration pump which is only activated when coolant is below 50°C. I was thinking it is there exactly counter this behavior.

Also it has a automatic fast idle when the coolant is cold.

 

[oneOf8billion]

I just discovered the following page in the repair manual. I see a major difference between the setting of fast idle speed in GCC and other markets. It is 1200 instead of 900 rpm. I think I would not have those problems, if it would idle at 1200 when the coolant is cold, since this about the speed I set it with the manual knob to start it.

For your information I bought the car while working in the UAE and brought back to Switzerland now. It is of course much colder in Switzerland now!