Fuel Flow ??? I could use your help

[rfc2307]

Good Morning, I have a 1981 FJ60 that I have been bringing back from the brink for about a year, now it has developed what to me are severe issues. I have read every "...can't idle, stumbling..." thread and thanx for that.

Most times, when I start it in the AM it perks right up. Pump the gas pedal two times, pull out the choke until the first click, put it in neutral, turn the key, idle for five minutes. But, lately, the gremlins have come out.

After about two or three miles, the rig: (1.) has big trouble idling on it's own, if I pull out the choke, all the way, it will idle at about 1K and that is it; (2.) it shakes, I mean SHAKES, violently at idle, it sounds like there are explosions coming from the header tubes; (3.) if I goose the gas pedal, the idle straightens out for a nano-second then startes a buckin' again.

When I get it into the garage and push in the choke, it idles at about 100 RPM and spews out smoke.

While it is doing this it appears that the fuel filter (new filter and fuel pump) is about 1/32 full [what is the normal, well running fuel level? anyone know??].

Vacuum is good, checked with a vacuum gauge.

Gas Cap also checked, with a new one and a new one I drilled a hole in, no change.

Spark is good. Tried the stock coil and an aftermarket, both with new plugs, wires, rotor and cap.

My gut is telling me it is gack in the gas tank and/or fuel lines, between the filter and the gas tank.

If anyone else has experienced this, and has a quicker fixer upper, I will be in your debt for that information.

I have not tried the idle at 2500 and put my hand over the top of the carb trick, but that is on tap for this evenings festivities.

This is a Troll Hole carb on the rig for about a year, I could re-build it or have it rebuilt, if it wasn't for that dang near empty fuel filter.

Look forward to your assistance.

 

[cruiserbrandon]

disconect the fuel line pre filter and run a piece of fuel line into a fuel container and run it for a while and see what the filter does just to make sure you dont have a small hole to pull air in the fuel lines, the fuel filter is under a light vacuum so it should be almost pure fuel just a small air bubble at the top.

 

[brett76]

or just check the fuel in your sight glass and see that its there. you can also unhook your fuel line and have someone turn it over while you watch the gas pump out to see if its getting fuel.

also its seems that lately a few people with trollholes after about a year to have float problems. the seem to be soaking up fuel and sinking

 

[rfc2307]

Thanx.

When I am experiencing these problems, I can not see ANY fuel in the sight glass.

New Fuel Pump. New Fuel Filter.

Not certain what a fuel pre-filter is or where to find it?

Next steps will be to: (1.) remove from gas tank line at the fuel filter and blow compressed air back into the gas tank; (2.) remove line at charcoal canister and check for vacuum there.

 

[brett76]

seriously unhook you gas line at the carb and turn it over. you will see if you are getting fuel.

if your float is sinking you wont see any gas in the sight glass

 

[the gimpey one]

Yep just put a solo cup under the line to catch the fuel.

 

[2mbb]

you should see the fuel level in the carb sight glass. If you don't, the carburetor bowl is either not full enough (fuel delivery problems) or too full (float sinking or stuck needle valve). You kinda need to figure out which one is happening. When you have observed this condition and the engine is stopped, you could open one of the main jet access bolts at the bottom of the float bowl and drain a little fluid out. If you don't see any change in the window, then the fuel level is low. If you see the level drop through the window, then the bowl is full.

I think you say you have a new fuel pump and new fuel filter. The filter is located upstream of the pump (between the tank and the pump). There should also be a screen right at the carburetor fuel inlet. That could be clogged too.

 

[rfc2307]

UPDATE:

Removed the gas tank side hose from fuel filter and blew compressed air back into the tank. Reattached hose. Truck started right up and idled like a champ. Fuel filter completely filled with fuel. A few minutes later, fuel filter was down to about 1/8 full of fuel again and idle was stumbling at about 100 RPM.

At this point, it would seem to be a gas tank problem / fuel like problem.

I agree that it could be a carb float problem as well, but the fuel filter being devoid of fuel is, to me, a pretty strong indicator of gas tank / fuel line problem.

Still would appreciate any and all advise.

 

[gregnash]

Since you carb is a Trollhole I would call Marshall to help diagnose but it seems that you have narrowed it down to the fuel and possibly the pickup assembly in the tank. Since this is 60 take the top of the tank out (sending unit?) and see what you can see in there.

And the dumb question, do you know if the gas tank recall has been done? If not look for the thread and give Toyota a call, or go to your local dealership and tell them they have to look in the OLD system to see.

 

[Dodobo]

I'd start with whats easiest and replace all the old soft fuel lines with new hose and check all the hard lines for any weird kinks or dents.

Also check to see that the fuel line routing to and from the tank is correct - I believe the lower hard line on the frame goes from tank to pump and connects to the more forward barb on the tank. The return line is the upper one the frame rail and connects to the further back fuel tank barb.

Good luck and keep us posted with progress.

 

[Lead Head]

UPDATE:

Removed the gas tank side hose from fuel filter and blew compressed air back into the tank. Reattached hose. Truck started right up and idled like a champ. Fuel filter completely filled with fuel. A few minutes later, fuel filter was down to about 1/8 full of fuel again and idle was stumbling at about 100 RPM.

At this point, it would seem to be a gas tank problem / fuel like problem.

I agree that it could be a carb float problem as well, but the fuel filter being devoid of fuel is, to me, a pretty strong indicator of gas tank / fuel line problem.

Still would appreciate any and all advise.

Fuel filters are funny things, and can often look near empty despite flowing plenty of fuel. I see it all the time.

Do as the other guys suggested. Take the fuel line off at the carb, and see if you're actually getting good fuel flow into a cup.

 

[mike8560]

Im having the same problems you are and have done the same things.
new filter, new pump, blew air into lines but not enough I think . the pressure wasn't very high. but none the less it ran better for about 10 days and now almost no fuel in filter at all.
im going to try to push more air (psi) through lines. my sight glass level is at the very bottom but it was like that before I put new parts on.

 

[Elbert]

pull the gas tank.....and get it cleaned or replace /OP.

 

[mike8560]

OK. But what I'm asking is what's inside the tank that could cause this issue?
Is there just a hose stuck in a tank because the tank doesn't leak . What could go wrong with it.

 

[Elbert]

rust, crud from years of crappy gas and potentially water in the gas, a combination of rust & crud... Potentially!

 

[Slow Left]

It's kind of a left field (...baseball term...) question, but have you checked for misfire? In the OP, rfc2307 described one of the symptoms as 'rough running.' Just wondering if one of the pistons is misfiring.

Check to make sure that the spark plug wires are in 'their secure and upright positions, with seat belts correctly fastened', then, with the engine idling, unattach each wire (one at a time) and listen for a change in engine sound. If there is not a change in idle sound, then that cylinder (the one with the disconnected spark plug wire) is misfiring.

 

[Bear Lake Cruiser]

Old tank or the new one after recall?