1FZ-Carb bogging off idle (1 Viewer)

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Joined
Jan 2, 2022
Threads
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Location
Nepal
Namaste All from Nepal,

I have a FZJ-80 with Carb and the folks at 80 series asked me to post this issue here as the carbs are similar.

1. Car bogs down off idle, when I let go of accelerator and then press again, it hesitates/bogs and jerks.
2. The spark plugs are black with carbon.
3. I had muffler leak down the tail pipe, I got it fixed and it sounds better but idle is not as smooth as it should and the hesitation still persists.

I am posting pics of the carb. Please help me to troubleshoot this.

Thank you very much.

tempImageeH2V1A.png


tempImageLOMLp8.png
 
First thing I’d replace without second guessing is the accelerator pump.
Replace that with a high quality piston (preferably Toyota’s) then see if that fixed the hesitation.

The AP’s purpose is to forcefully squirt gasoline into the manifold when the gas pedal is suddenly pushed down to provide fast fuel delivery.
When the pump isn’t pumping well, when you press on the gas pedal, it creates a momentary vacuum leak before the engine can suck the fuel through the jets.

Drawing below is from a 2F carb but carbs are similar.
Replacing the accelerator pump won’t help rough idle though, it only prevents hesitation when first stepping on the gas pedal.

66AFCD5A-52ED-42F7-95D4-3F460D90AE42.png
 
Thank you OSS, I will need to source part from Dubai because this is very rare engine and rare carb so parts are unavailable locally. Is there a way to verify whether the accelerator pump is behaving normally or not optimally? Thanks.
 
1. Remove the air cleaner cover so you can see straight down into the carburetor throat.

2. Grab the accelerator linkage somewhere on the carb and twist it/pull it( whatever action it required) quickly to fully actuate full throttle.

Each time you do that, you should see a very strong stream of gasoline squirting forcefully down into the carburetor throat.
If you do it too many times, you could pump the float bowl dry, but the first few pumps should squirt fuel with force.

If the gasoline kind of just dribbles out or doesn’t squirt with vigor, the accelerator pump piston seal is worn and not pumping like it should.

But if the carburetor has never been cleaned out/rebuilt since the car was new, it’s past time to do that.
 
Hi OSS,

I check the pump like you said and I see a spray coming out of it I have made a video but I dont if it will be clear enough for you.



Thanking you.
 
Namaste All from Nepal,

I have a FZJ-80 with Carb and the folks at 80 series asked me to post this issue here as the carbs are similar.

1. Car bogs down off idle, when I let go of accelerator and then press again, it hesitates/bogs and jerks.
2. The spark plugs are black with carbon.
3. I had muffler leak down the tail pipe, I got it fixed and it sounds better but idle is not as smooth as it should and the hesitation still persists.

I am posting pics of the carb. Please help me to troubleshoot this.

Thank you very much.

View attachment 2889505

View attachment 2889506



- I would Change YOUR Fuel Filter for GOOD measure 100% YES

- @OSS is very wise fellow member , and the accel pump is a good place to start too !

Hello ,
Namaste My Friend From the Great NEPAL ! :)

- it would help to have your modle year and
this CODE off off your ENGINE BAY DATA ID plate too ?

-
  • FZJ80L-GCMEUV EXAMPLE ONLY :

- i went with a 95-98 ,

- i took a @3_puppies WAG on the CODE and Year ?


- you want to confirm and verify the , SOLONOID , Throttle Valve , shown below is working properly , ?

- they can go bad OFTEN on a NON-USA 1FZ carb FZJ80- like you have going on ,

- below is parts diagrams to help you make a speedy Repair ......:cool:




21934SOLENOID, THROTTLE VALVE
21062-612701990.11 - 1992.01
21062-610101990.01 - 1992.01
21062-612511990.01 - 1992.08
21062-660101992.08 - 2001.09




1641965352688.png







part # 23300-66030

1641965641764.png



1641966129788.png



1641966186535.png


1641965936382.png





1641966058589.png
 
Last edited:
- I would Change YOUR Fuel Filter for GOOD measure 100% YES

- @OSS is very wise fellow member , and the accel pump is a good place to start too !

Hello My Friend From the Great NEPAL ! :)

- it would help to have your modle year and
this CODE off off your ENGINE BAY DATA ID plate too ?

-
  • FZJ80L-GCMEUV EXAMPLE ONLY :

- i went with a 95-98 ,

- i took a @3_puppies WAG on the CODE and Year ?


- you want to confirm and verify the , SOLONOID , Throttle Valve , shown below is working properly , ?

- they can go bad OFTEN on a NON-USA 1FZ carb FZJ80- like you have going on ,

- below is parts diagrams to help you make a speedy Repair ......:cool:




21934SOLENOID, THROTTLE VALVE
21062-612701990.11 - 1992.01
21062-610101990.01 - 1992.01
21062-612511990.01 - 1992.08
21062-660101992.08 - 2001.09




View attachment 2891204






part # 23300-66030

View attachment 2891205
Here you are my friend.

tempImageLR5Umh.png
 
Namaste All from Nepal,

I have a FZJ-80 with Carb and the folks at 80 series asked me to post this issue here as the carbs are similar.

1. Car bogs down off idle, when I let go of accelerator and then press again, it hesitates/bogs and jerks.
2. The spark plugs are black with carbon.
3. I had muffler leak down the tail pipe, I got it fixed and it sounds better but idle is not as smooth as it should and the hesitation still persists.

I am posting pics of the carb. Please help me to troubleshoot this.

Thank you very much.

View attachment 2889505

View attachment 2889506


also ,

make sure these wires are NOT severed or broken ?

i can see BARE wire copper strands ?

possible issue ?





tempImageLOMLp8.png
 
thanks this helps :

your FZJ80 Production date is : 1/95

or


Search FRAME TOYOTA

Search

BrandRegionModelModel codeEngineRelease datevdate
TOYOTAgrLAND CRUISERFZJ80R-GCMRU1FZF1992.01 - 1998.01199501

  • Engine, fuel system[FZJ80R-GCMRU]

Engine, fuel system TOYOTA LAND CRUISER[FJ80,HDJ80,HZJ80,FZJ80] (ASIA and MIDDLE EAST)



- 21100-66030 carburetor assy .

- 04211-66030 carburetor re-build kit

-

21062- 66010SOLENOID, THROTTLE VALVE


possible cause .......fyi








1641967167691.png



1641967155749.png


1641967142184.png





1641967213752.png



download (13).jpg
download (12).jpg
 
Last edited:
thanks this helps :

your FZJ80 Production date is : 1/95

or


Search FRAME TOYOTA

Search

BrandRegionModelModel codeEngineRelease datevdate
TOYOTAgrLAND CRUISERFZJ80R-GCMRU1FZF1992.01 - 1998.01199501

  • Engine, fuel system[FZJ80R-GCMRU]

Engine, fuel system TOYOTA LAND CRUISER[FJ80,HDJ80,HZJ80,FZJ80] (ASIA and MIDDLE EAST)



- 21100-66030 carburetor assy .

- 04211-66030 carburetor re-build kit

-

21062- 66010SOLENOID, THROTTLE VALVE


possible cause .......fyi








View attachment 2891221


View attachment 2891220

View attachment 2891219




View attachment 2891222


View attachment 2891224View attachment 2891223
SOLENOID, THROTTLE VALVE. --- What is the function of this?
 
SOLENOID, THROTTLE VALVE. --- What is the function of this?



well .........

- it allows fuel to pass when key is ON

- when key off CUTS fuel flow

- a BAD one can do what your truck is doing from my experience
 
Update on this,

The car stumbles less in when in 10 degree BTDC timing but stumbles more on 3 degree BTDC. However, the stumble hasnt gone. it gets worse when I press gas pedal and release it and again press it. This is where the stumble/bog is more pronounced.
 
This pipe is not connected anywhere. Can the gurus, please let me know where it should connect and what is the purpose of this pipe. Today while trying to troubleshoot accelerator pump, I could see petrol leaking out of it when accelerator pump was being repeated pushed back and forth.

tempImageizOIV7.png
 
I’m not familiar with that carburetor so I don’t know what that pipe is used for. But regardless, plug it and see what happens.
No carburetor on any vehicle should have a pipe open like that to atmosphere.
Maybe it’s a float bowl vent pipe? I don’t know.
There’s got to be somewhere where someone knows about this carburetor. Nobody on this forum is familiar with it.
 
This pipe is not connected anywhere. Can the gurus, please let me know where it should connect and what is the purpose of this pipe. Today while trying to troubleshoot accelerator pump, I could see petrol leaking out of it when accelerator pump was being repeated pushed back and forth.

View attachment 2896554
I’m not familiar with that carburetor so I don’t know what that pipe is used for. But regardless, plug it and see what happens.
No carburetor on any vehicle should have a pipe open like that to atmosphere.
Maybe it’s a float bowl vent pipe? I don’t know.
There’s got to be somewhere where someone knows about this carburetor. Nobody on this forum is familiar with it.



we must thank mr . Eagle for posting what i had ZERO luck finding on my own?

i hope this helps ? .




maybe @WarDamnEagle , can chime in directly here and pinpoint the END game location of the ROUGE open carb base Vacuum Manifold absolute source of a klear leak

i think it should be considered




i bet Greg will agree with me , there is MORE to this MYSTERY then just a open carb brass fitting ?

there always is ,. he is much more tech savey on a 1FZ CARB NON-USA Saudi-Spec platform then i am




lets get you repaired up FSM all proper ........:)




DSCN0683 - Copy.JPG

 
I have that exact engine and carburetor on my 1994 FZJ75. I think @ToyotaMatt gives me far too much credit for my knowledge of said carburetor, or any carburetor for that matter. I can look to see what is attached to that nipple but it will be Thursday before I can do so as I am out of town until then.
 
I have that exact engine and carburetor on my 1994 FZJ75. I think @ToyotaMatt gives me far too much credit for my knowledge of said carburetor, or any carburetor for that matter. I can look to see what is attached to that nipple but it will be Thursday before I can do so as I am out of town until then.


thanks for your valued input and willingness to trace the missing vacuum hose to its end game source location ......:)
 
Update: I checked the a pic i found in this forum and according to it does not go anywhere. It is capped.

I have taken to a new mechanic. He says the vacuum advancer was connected to the wrong port. But he seems confused to where the line from line from the white nipple in air cleaner cover connects to. Can anyone please with vacuum lines. We tried to to figure out from the 3rd picture. But we were confused.

There are two nipples facing the front of the car and 3 nipples on the engine side of the carb.

One of the front facing nipple is plugged and next one is connected to HAC.
Out of 3 nipples on engine side one is plugged and rest two are connected. The mechanic seems to be confused on where these two nipples go, one goes to HAC and next goes to Distributor advance?

vacuum.jpeg


tempImage3v2wQb.png


1fz-f (carb)1.jpg
 
But he seems confused to where the line from line from the white nipple in air cleaner cover connects to.
That white vacuum hose fitting on top of the air cleaner seems to be a controlled bleed off valve for another vacuum actuated component.
The Toyota drawing shows a vacuum hose connected to it then it snakes down to the gas filter (vacuum source).
The center of the air cleaner cover is a source of filtered air.

EAFB4E57-6520-40BE-AFAD-FECD5F29D4E0.jpeg
 
Thank you very much OSS,

I have tried to figure out where other lines go, I am attaching a simple schematic I tried to draw myself. Can anyone please confirm if I am doing it right or wrong?

Screen Shot 2022-01-19 at 21.26.28.png
 

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