2F stumbles at idle (sometimes)

[Wadesters]

I have a restored 1980 FJ40. Engine was rebuilt 8 years ago (no smog but has catalytic converter) and probably has not had more than 2k miles since then. It is used regularly just not for long distances. Recently for good measure I replaced: wires, plugs, all filters. It runs well with lots of power but sometimes after hot it will idle really low or stall. Other times it is just fine. The times it wants to stall if I pull the choke out a slight bit to get the idle up, thus not stalling, it is ok. Run it a little longer and then it is fine, push choke back in. So the problem is intermittent. I am thinking it must be something carburetor related. Have thought about going EFI but just not sure it is for me. I had this setup once before on another 2f and hated hearing the fuel pump all the time. Yes, I am picky. It is a soft top so I only use it in summer. I am thinking since it will not be used all winter, to send the carb to Jim C. Before I do I thought I would check with the professionals on this forum. Thank you!!

 

[CruiserInProgress]

In addition to a possible carb issue, the use of a little choke to maintain idle might also suggest a vacuum leak somewhere (manifold gasket, carb insulator, brake booster, vacuum advance, pcv line, etc.).

I struggled with a similar issue on my desmogged 79 2F, and attempted to isolate any possible leaks, finally discovering a intake manifold gasket leak.

 

[Wadesters]

Thanks! I'll check. I do get a slight whistle when I shut engine off (not sure that is related)

 

[3_puppies]

for the stalling no idle,
I was thinking something in the fuel cut solenoid circuit, either internal in carb, or wiring to solenoid.

 

[Pighead]

What distributor do you have and what is the timing set at?

edit: Also, if you're going to send your carb off to a Guru, maybe send your dizzy too.

 

[Wadesters]

Stock distributor. When I changed the wires coil wire was stuck in distributor cap. I broke the cap getting that wire out. Then I found how hard it is to find a 1980 2f distributor cap…. Impossible. I was lucky enough to find a used one that looked good (no other options).

 

[igotta40]

You might consider adding a vacuum gauge to your instrument panel, they are pretty informative.

 

[Wadesters]

I have noticed once I shut it down there is a "whistle" for a few seconds when I shut it off. No vacuum leaks that I see. Going to make sure manifold bolts are tight when it cools off.

 

[CruiserInProgress]

I have noticed once I shut it down there is a "whistle" for a few seconds when I shut it off. No vacuum leaks that I see. Going to make sure manifold bolts are tight when it cools off.

The whistle sounds curious. Do you hear it with the engine running? Can you locate the source?

About finding a possible vacuum leak, you might try spraying some something (starter spray, wd40, butane, etc), around suspect areas while idling, to see if your RPM is affected, but please be careful. I tried a little butane from my torch, thinking that might be safer and more controllable, but didn't notice any difference, even around my intake gasket that I found later was leaking due to age.

You can also try to better isolate leaks from hoses coming into your intake manifold (vacuum advance, brake booster, pcv), but momentarily plugging or clamping hoses to see if you notice a difference in RPM.

 

[B y r o n]

Is the whistle sound coming from the gas tank? If you are getting vacuum in the tank it could cause fuel starvation issues.

 

[Wadesters]

I can’t thank everyone enough for taking the time to help me. Ran it by a more skilled mechanics house today and he found a vacuum leak just has others suggested. So far running and idling great

 

[igotta40]

Where was the vacuum leak?

 

[Wadesters]

One of the hoses connected to manifold was unhooked.