1985 FJ60 stalls at idle after going down hill (1 Viewer)

[Dave L]

Hi All,

me: limited mechanical knowledge, mainly learning from youtube and here. have learned a few basics like changing brake pads, rotors, brake booster and carb with a bit of help.

the FJ60: was desmogged by PO. had a new carburetor from city racer last year. fuel tank was making the sucking noise when I popped the cap so I disconnected the hose from the canister about a year ago. put in a duralast vc120 charcoal canister last month. 198K so far. got poor compression when it was tested over a year ago. IIRC the average was around 100 with some a bit lower, some higher, none above 120. have been finding carbon residue on the spark plugs for a while and have to clean them off fairly often to keep them firing. put in an oil catch bottle last summer - caught oil used to be dark but has become milky over the last 6 months. Had a mechanic put in a new clutch after I got it. Have been preparing myself for the inevitable engine rebuild from a professional that I think it needs soon.

now to the current problem that has been vexing me - after going down a hill and coming to stop at a light or junction where the engine idles, it dies. Feels like its being flooded and needs a while and a bit of running the starter and pumping the gas before it will go again. sometimes I pull all the plugs and clean them - not sure if this helps, but it gives me something to do.

Have tried adjusting the carb float level with the tab you bend. tried the recommended 7.5 mm gap but this starved it completely. adjusted it every which way, but the best I can get is to have the level just visible at the top of the window. Problem persists.

 

[Masonblackmon]

Do you have a mechanical or electric fuel pump?
How dirty are your fuel filters?
What altitude are you at?

 

[g-man]

If the gas is visible at the top of the site window you either need to readjust the float or inspect the rubber tip of the needle valve for damage. You can also physically blow throw the gas passage when you close and open the float to make sure that it is not leaking. Fuel can slip by the needle if it isn't seating and sealing causing the bowl to overfill. The 1980 2f engine FSM shows floats setting for USA and non USA to be 6mm and 1.1 mm

 

[OSS]

My suspicion - faulty fuel pump.
But just my first guess.

 

[Dave L]

Do you have a mechanical or electric fuel pump?
How dirty are your fuel filters?
What altitude are you at?

Thanks for the reply. mechanical. I changed the fuel filter - didn't make a difference. I'm not far above sea-level

 

[Dave L]

If the gas is visible at the top of the site window you either need to readjust the float or inspect the rubber tip of the needle valve for damage. You can also physically blow throw the gas passage when you close and open the float to make sure that it is not leaking. Fuel can slip by the needle if it isn't seating and sealing causing the bowl to overfill. The 1980 2f engine FSM shows floats setting for USA and non USA to be 6mm and 1.1 mm

View attachment 3311104

I didn't realize that there was a part B to adjust - thanks! However with any gap at all in fig 6-132 the bowl is filled above the window. I had a good look at the needle for damage - looks fine to me. Yes, I tried blowing through it as I wiggle the float to see if it closes the valve. However if I can do that it will still overfill. I had to adjust it so that you can't blow through just to get the bowl fill level visible in the very top of the window. I figure that the hydraulic pressure from the pump must be able to force the valve down on it's spring unless there's enough pressure below from the float to prevent that - whereas blowing isn't able to overcome that.

I'm definitely out of my depth and missing something obvious. Like the time I tried to get the brake drums off with the handbrake on

 

[Dave L]

My suspicion - faulty fuel pump.
But just my first guess.

Thanks - I've been looking at replacement fuel pumps and wondering if that could be the cause. Any way to test that theory please?

But how would that lead to flooding, or flooding like symptoms?

 

[OSS]

The (2) main jets in the carburetor float bowl are located at the rear of the bowl. When the car (and engine) is tilted nose down, the fuel level isn’t level in the bowl because the carburetor is now tilted.
The fuel is lower in the rear and higher in the front of the bowl.

Maybe…. something is going on with the float or pump or needle valve seat that is sticking in a downhill position when the car levels out after going downhill.
Just thinking out loud. Maybe not the culprit.

 

[g-man]

I didn't realize that there was a part B to adjust - thanks! However with any gap at all in fig 6-132 the bowl is filled above the window. I had a good look at the needle for damage - looks fine to me. Yes, I tried blowing through it as I wiggle the float to see if it closes the valve. However if I can do that it will still overfill. I had to adjust it so that you can't blow through just to get the bowl fill level visible in the very top of the window. I figure that the hydraulic pressure from the pump must be able to force the valve down on it's spring unless there's enough pressure below from the float to prevent that - whereas blowing isn't able to overcome that.

I'm definitely out of my depth and missing something obvious. Like the time I tried to get the brake drums off with the handbrake on

Pressurized fuel from the pump doesn't push the needle seat closed. It only gives the fuel positive pressure so it will go in the carb bowl once the float gets low and opens the valve. When the float is in the "bowl full position" it is pushing down on the pin/spring and needle valve and will be enough pressure to hold the needle valve/seat in a closed position. Blowing in the fuel line connection only tests to see that the valve when closed by the float is actually tight and not allowing air/ and thus fuel to bypass it. You can test to see if no air is bypassing the needle valve and seat by holding that part blowing on the fuel line connection and manipulating the float to the full position. Air should flow thru until you have the float all the way up, then no air should flow through. If this test works then that should be enough pressure to keep the fuel out of the bowl until fuel from the bowl is consumed enough by the engine to allow the float to drop and open the valve...allowing more fuel to come from the fuel line/pump. Other faults that happen are a cracked float (very rare) filling with fuel will stay down even though the fuel level in the bowl is full, also the valve can get stuck with some trash in it and fail to close. (more common)

If your not good at this stuff the 1st thing I recommend it that you get a flashlight and put it on the sight glass, Then shake the vehicle by bumping the fender with your hip to shake the fuel in the bowl so you can really see if it's over full or on the middle mark of the sight glass.

their maybe some trash or water in the fuel line/tank and bowl. Disconnect the spark plug wire from the coil and have someone crank the motor for a few seconds while you hold the disconnected fuel line to fill a clear mason jar. Fill it about 1/2 way. Is it milky or is the fuel clear and clean? If you put it down and come back in a few minutes has any water or trash settled to the bottom?

 

[ceylonfj40nut]

I would check if your idle control solenoid on the carb is working as it should. Google it.

 

[Masonblackmon]

I’ve never messed with the factory carb only webbers so I’ll be of no help. But I know with a Webber proper jetting for the altitude (I’m at 5000) and a proper electric fuel pump does wonders.

Maybe install a fuel pressure gauge to make sure it’s a steady even supply of fuel and a line isn’t partially clogged?

 

[g-man]

Going down a steep hill at speed then stopping hard could be stirring up the fuel and any trash or water in it causing a stall.

 

[Dave L]

Pressurized fuel from the pump doesn't push the needle seat closed. It only gives the fuel positive pressure so it will go in the carb bowl once the float gets low and opens the valve. When the float is in the "bowl full position" it is pushing down on the pin/spring and needle valve and will be enough pressure to hold the needle valve/seat in a closed position. Blowing in the fuel line connection only tests to see that the valve when closed by the float is actually tight and not allowing air/ and thus fuel to bypass it. You can test to see if no air is bypassing the needle valve and seat by holding that part blowing on the fuel line connection and manipulating the float to the full position. Air should flow thru until you have the float all the way up, then no air should flow through. If this test works then that should be enough pressure to keep the fuel out of the bowl until fuel from the bowl is consumed enough by the engine to allow the float to drop and open the valve...allowing more fuel to come from the fuel line/pump. Other faults that happen are a cracked float (very rare) filling with fuel will stay down even though the fuel level in the bowl is full, also the valve can get stuck with some trash in it and fail to close. (more common)

If your not good at this stuff the 1st thing I recommend it that you get a flashlight and put it on the sight glass, Then shake the vehicle by bumping the fender with your hip to shake the fuel in the bowl so you can really see if it's over full or on the middle mark of the sight glass.

their maybe some trash or water in the fuel line/tank and bowl. Disconnect the spark plug wire from the coil and have someone crank the motor for a few seconds while you hold the disconnected fuel line to fill a clear mason jar. Fill it about 1/2 way. Is it milky or is the fuel clear and clean? If you put it down and come back in a few minutes has any water or trash settled to the bottom?

I did the blow test - even if I could blow a tiny amount with the float full down then it overfills the bowl. Only when the tab is bent to prevent me blowing through it at any position of the float can I get it so that the level is even visible in the window and then it's right at the top.

Hence why I'm assuming that pump pressure is playing a part in opening the valve on it's little spring needle thingy - perhaps I did a bad job of articulating that. Never tried to say that pump pressure was closing the valve, only assisting in opening it - maybe

I did see some silt in the bottom of the float chamber one time I opened it up, maybe some water too, but I assumed I must have got that in there somehow when I was opening it up - could that produce the symptoms? contaminated/bad fuel?

 

[g-man]

When you blow through the fuel line fitting air should easily move through the needle and seat. Then when the flow comes to the full level (6mm from the body) there should be NO air pushing through. Yes even a small amount would mean that fuel is also pushing through. I don't believe that the fuel pressure from the pump in any way is supposed to "play a part in opening the valve". I think the spring may be some kind of buffer in case the float were to bounce or jiggle around with the vehicle moving . It gives it a little forgiveness so the needle valve doesn't immediately open at every little movement. Just a guess.

Yes, do remove the water and silk from the bottom of the bowl and check the fuel in the tank and line by using the mason jar method I mentioned earlier.

Also make sure you have all 3 parts of the needle valve seen here:

and make sure the float hinge pin is not worn...should be nice and round and smooth so the float doesn't hang up.

 

[Dave L]

so there is a little plunger & spring thingy in the top of the carb that I see labelled as the "power piston" here:

CARBURETOR / toyota | part list｜JP-CarParts.com - http://jp-carparts.com/toyota/partlist.php?maker=toyota&type=791130&cartype=7&fig=2103

if that was sticking then would it produce the symptoms I'm getting?

when I last had it apart I took it out, had a look and put it back. it didn't seem to move as freely as the one on my old carb - hesitates to rise up on it's spring sometimes - whereas the old one moves freely

 

[Dave L]

When you blow through the fuel line fitting air should easily move through the needle and seat. Then when the flow comes to the full level (6mm from the body) there should be NO air pushing through. Yes even a small amount would mean that fuel is also pushing through. I don't believe that the fuel pressure from the pump in any way is supposed to "play a part in opening the valve". I think the spring may be some kind of buffer in case the float were to bounce or jiggle around with the vehicle moving . It gives it a little forgiveness so the needle valve doesn't immediately open at every little movement. Just a guess.

Yes, do remove the water and silk from the bottom of the bowl and check the fuel in the tank and line by using the mason jar method I mentioned earlier.

Also make sure you have all 3 parts of the needle valve seen here:

View attachment 3312674

and make sure the float hinge pin is not worn...should be nice and round and smooth so the float doesn't hang up.

Tried the mason jar method - no silt or water seen

 

[Dave L]

When you blow through the fuel line fitting air should easily move through the needle and seat. Then when the flow comes to the full level (6mm from the body) there should be NO air pushing through. Yes even a small amount would mean that fuel is also pushing through. I don't believe that the fuel pressure from the pump in any way is supposed to "play a part in opening the valve". I think the spring may be some kind of buffer in case the float were to bounce or jiggle around with the vehicle moving . It gives it a little forgiveness so the needle valve doesn't immediately open at every little movement. Just a guess.

Yes, do remove the water and silk from the bottom of the bowl and check the fuel in the tank and line by using the mason jar method I mentioned earlier.

Also make sure you have all 3 parts of the needle valve seen here:

View attachment 3312674

and make sure the float hinge pin is not worn...should be nice and round and smooth so the float doesn't hang up.

Hi G-man,

So I got the chance to take it apart today and check some of the things you said to. Nothing obvious.

Polished the power piston a tiny bit as I was concerned it was sticking open.

Back together and it runs fine - except when it randomly tries to die at idle. it's like the revs are trying to drop, you can keep it going with the gas pedal or the choke, but if you don't then it will putter out. Almost like it's not firing on all cylinders or something. Most of the time it's fine, you can leave it running at idle or drive it, but occasionally it just dies and doesn't want to start.

Only interesting thing I noted this time that I never saw before was that there was some carbon deposits on the nozzle of the carb barrel closest to the engine....

Could this be connected? Broken valve? timing?

Tired of playing guessing games with only a basic grasp of this. Did have it booked with a mechanic I trust for Monday but he said he's busy and can't get it in for anther month.

Any ideas please?

Dave

 

[ceylonfj40nut]

Do you have another carb or a friend who could lend you one to see if resolves the issue? Flame me, but can try a weber carb to see it improves. A month down is a long time

 

[g-man]

Is the gas even with the center of the sight window now? FYI...a clogged egr valve will cause stalls also. I once cleared a sticking clogged EGR valve simply by beating it with a hammer as the engine rev'd. Are you completely desmogged or do you have an EGR valve? Agree with above to swap out carbs just as a process of elimination. If you put another carb on and the problem persists you should check for vacuum leaks. And test the engine vacuum ..it will tell you much about the health of your engine. If you suspect several cylinders are not firing you should test your spark plugs to make sure they are firing. Double check your firing order too.

Reading your original post you said you have milky oil ie coolant getting into the oil, also your spark plugs are getting fouled often. Maybe time to pull the cylinder head and have a valve job done and have the head magfluxed for cracks. I did mine at about 280k miles and now have 322k so It has bought me some time. I did have cracks in the head with coolant puddling on top of the head under the valve cover and pouring over onto the lifters. I had to source another used cylinder head. the are no longer available.

If your plugs are getting fouled with dry carbon I'd suspect the exhaust valves(an easier fix) If they are getting oily black then maybe some blow-by from the piston rings (more of a total rebuild here). Either way you'll need to address this sooner or later.

 

[Dave L]

turns out my float didn't float

kept tinkering with it, adjusting the tabs to try and get the level right. until I tried shaking the float. couldn't feel any liquid. tried putting it in the bowl. sank. got the old carb and took the float off - result!

like the time I went up in the mountains and my compass kept pointing every which way, making no sense at all. took me three days to figure out that there was a magnet in my mittens for folding back the finger pocket.

think I'll still get it to a professional to have a proper look at it, but very thankful that I figured out the immediate problem - thanks for all your help!