[ cold starts > warm starts ] i'm stumped

Joined
Mar 21, 2019
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93
Location
Kitty Hawk, North Carolina
Hi everyone,
I've been working on this '85 FJ60 for a while and I finally got rid of all the vacuum leaks. But for whatever reason, It does not like to start when it is warm, say after driving 35 mph down a road, stopping, and starting it back up. I have to do some fancy footwork with the pedal to get it to start, and sometimes it will die, but always start back up. Not sure why.

When it is warm, it will crank for a solid 7 secs before it even fires.

Here is a video of a cold start before I took it out for a grocery run
 

ntdb

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Jan 10, 2020
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Seattle, WA
Has it always done this or just recently in that NC summer heat? Does your carb fan work? This could be caused by vapor lock.
 

gbogh

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Oct 5, 2016
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Chelan WA
FJ60s suffer from vapor lock. If you don't have the OEM carb heat shield installed (you mentioned having a Weber carb in your video) and/or your carb cooling fan working warm starts will be hard. I have have had to wait up to 30 minutes when it's warm out for my 60 to start when this happens. Solutions include getting your carb cooling fan working, and insulating the fuel as it goes to the carb via heat shield or aftermarket insulation.
 

klinetime574

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Jul 23, 2006
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Chicagoland, IL
 
 
I’m betting your choke isn’t hooked up or isn’t operating correctly. I never understood how it worked. I ran a wire, but never saw it actually working. I fiddled with the choke assembly so the choke plate was open all the time. Never had a problem with hot or cold starts when I lived in Texas.
 
Joined
Mar 21, 2019
Messages
93
Location
Kitty Hawk, North Carolina
How should I get the fan working. It plugs into a big bundle of wires, and it looks pretty intimidating. Where is the temperature probe? How can I "hack" the carb fan to make it work with my ghetto desmog?

@klinetime574 my choke is weird, but it is hooked up properly to switched ignition source. Not sure what the issue could be...
 

klinetime574

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Jul 23, 2006
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How should I get the fan working. It plugs into a big bundle of wires, and it looks pretty intimidating. Where is the temperature probe? How can I "hack" the carb fan to make it work with my ghetto desmog?

@klinetime574 my choke is weird, but it is hooked up properly to switched ignition source. Not sure what the issue could be...

Temp probe is under the intake manifold. If the wire is still running to the sensor (and you want it to run every time the truck is shut off) remove the wire from the sensor and ground it. Fan runs for 20 mins or so every time the key is turned off.

You should remove your air cleaner during a hot start and look at your choke plate. If it’s closed the engine will not like starting. It’s right on top of one of the barrels. Also worth mentioning, the gas pedal should be fully depressed, turn the key, and release the gas when the engine fires up. That should help with the Weber because it’s a mechanical secondary.

HTH
 

2mbb

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Sep 1, 2003
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WC, CA
 
 
 
Just a comment that the video of what works doesn't help much to figure out what isn't working...

Not sure about the Weber, but the owners manual has different procedures for cold and hot starting. Cold starting should start with pumping the accelerator pedal to squirt gasoline into the intake to provide a rich mixture. For hot starting, you depress the accelerator once and HOLD IT DOWN. This fully opens the throttle to lean out the mixture during starting. Of course with the hot start, as soon as the engine catches you need to release the pedal. Caburetor engines often require some fancy footwork that FI engines don't.
 
Joined
Feb 2, 2016
Messages
205
Location
Oshkosh, WI
same thing on this end. I have dual batteries so carb cooling tube and fan are doing nothing. Spoke with Jim C and he said that these need to be driven more than my usual 10 mile or less drives and that the carb without cooling will act up. Nothing to do just 10 extra pumps on the gas and some choke.

I am full desmog
 
Joined
Mar 21, 2019
Messages
93
Location
Kitty Hawk, North Carolina
Alright, hear me out-
I have found the temp probe and all the wiring. Not too hard. Problem is, the only way I can get the fan to turn on is to wire it straight to the battery. I am thinking it is something with the emissions computer or something, so I am going to do it the redneck way. I would like to wire it up to a switch in the cabin, next to the steering wheel. Problem is, then I can't have it on a timer... Is there any way I can set a timer for it to run for like 5 mins after I turn the switch off after driving?
 

2mbb

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Here is the wiring diagram for the carb fan. I got this from the 1985 FJ60 supplement. I'm not sure why the fan doesn't show up in the normal manual...The fan is not connected to the emissions computer but there are shown 2 relays. The parts diagram only shows one, but when I look for the part number it gives 2, relay 1 and relay 2. I suppose they are both on the relay bus under the dash board, but I'm not sure--at lease one is there, I suppose. Relay 1 is a standard relay. Relay 2 looks like it is the device that decides when and for how long the fan stays on.

Carb Fan Wiring.jpg


1594246819127.png
 

2mbb

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Here is a picture of the "relay 2" for carb fan. So this is not a standard relay. I suppose it is located behind one of the side kick panels with similar boxes (eg. emissions computer, etc.).

1594247599856.png
 
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