Need Diagnostics Help - Hard Cold Starts, Banshee Squeal & Dies at Idle (1 Viewer)

[Pitter Patter]

Hello Everyone, need a bit of diagnostics help here.

1981 FJ40, all stock except it is lacking the dual diaphragm vacuum advance but I'm not at altitude. Been doing a ton of work on it but not much under the hood. Things that have changed under the hood since I acquired it in late 2019: valve adjustment, air filter, belts, and timing gear cover. The vehicle has always suffered from difficult cold starts. Full choke, turns over a couple of times, catches and runs for a second then quickly dies, do it again and it will run. This has progressively gotten worse and on cold mornings it may take 3 or 4 repeats of this before it runs. It also needs to idle for a long time before you can start letting in the choke. Before the belts and timing gear cover, the high pitched squeal started so those changes shouldn't be a part of the problem.

Squeal happens intermittently during idle and while driving. Does not seem to have any relation to braking, clutch, throttle. It just comes and goes. This morning the stalling at idle happened while coming to stop signs was a major issue. It did this at every stop sign on the way to work but then after sitting for about 9-10 hours at work, it started great and drove great on the way home. The squeal seems to go away as the entire engine compartment warms. I posted a video of it idling and revving here:

This was from today after I got home from work.
This video:

Shows the difficulty of the hard starts, the overall engine noise and you can hear the squeal begin at about 1:06, this was from this morning.

Sincerely appreciate any input on helping chase this issue down.

 

[fjc-man]

You may have done this test already - unplug connector to idle solenoid with ignition in the on position and see if the solenoid clicks. If I remember correctly, the emissions control unit provides the ground for the solenoid. It’s in the NC position with the key off. If the solenoid doesn’t retract there is no idle circuit fuel ( won’t run without choke). That ground signal maybe nonexistent or intermittent, depending on that control unit.

 

[jblatz]

For a stock set-up, it helps to follow the cold start procedure from the owner's manual. This is from an 83 manual, but applies to your rig as well.

 

[Pitter Patter]

Thanks guys, I’ll run through both those tests. Any advice related to the high pitch noise? Second posted video. Noise starts at 1:06.

 

[ceylonfj40nut]

Sounds like a manifold leak. Check intake and exhaust. By the sound it seems like a pressurized leak. Most likely exhaust. Did this suddenly happen or it’s always been there? Reason I ask, had similar symptoms once. Did a compression check and found weak compression in two cylinders.

 

[Pitter Patter]

For a stock set-up, it helps to follow the cold start procedure from the owner's manual. This is from an 83 manual, but applies to your rig as well.
View attachment 2829512

Appreciate the correct starting procedure. Good to know how it should operate. The cold starts are much more difficult than it states. The choke must remain fully out for a long time, any amount of depressing the choke causes the engine to die.

 

[Pitter Patter]

Sounds like a manifold leak. Check intake and exhaust. By the sound it seems like a pressurized leak. Most likely exhaust. Did this suddenly happen or it’s always been there? Reason I ask, had similar symptoms once. Did a compression check and found weak compression in two cylinders.

Makes sense. Yes there is weak compression on the second cylinder. As I recall the numbers were 150, 120, 135, 135, 135, 150 and a wet test on that low cylinder didn’t change the compression value. Wouldn’t surprise me if there is a manifold leak and it makes sense that it would go away as everything warms and expands. The entire exhaust system is leaking at every flange. I just ordered a new catalytic converter last week but it won’t be here until January… not sure what muffler to use since OEM isn’t available.

And yes, this noise started suddenly. No apparent ramp up. I’ll check for a manifold leak and report back once the sky stops dumping rain.

 

[Steamer]

Can you keep it running with the choke all the way in and giving it some throttle? That would be an indicator of the idle solenoid not functioning.

 

[Pitter Patter]

Can you keep it running with the choke all the way in and giving it some throttle? That would be an indicator of the idle solenoid not functioning.

Nope, throttle + choke in causes a stall

 

[Steamer]

Nope, throttle + choke in causes a stall

Then I'd be guessing major vacuum leak or junk in the carb.

 

[whitey45]

Almost guaranteed vacuum leak, spray the intake with carb clean while its running, this will locate the leak. If your exhaust leaks, you might as well do the much dreaded intake/exhaust gaskets!

 

[fjc-man]

Makes sense. Yes there is weak compression on the second cylinder. As I recall the numbers were 150, 120, 135, 135, 135, 150 and a wet test on that low cylinder didn’t change the compression value. Wouldn’t surprise me if there is a manifold leak and it makes sense that it would go away as everything warms and expands. The entire exhaust system is leaking at every flange. I just ordered a new catalytic converter last week but it won’t be here until January… not sure what muffler to use since OEM isn’t available.

And yes, this noise started suddenly. No apparent ramp up. I’ll check for a manifold leak and report back once the sky stops dumping rain.

You can still get an OEM muffler 17430-61120. Order it from your dealers online store price of 226.00

 

[Pitter Patter]

You can still get an OEM muffler 17430-61120. Order it from your dealers online store price of 226.00

Just tried that. It says available but I got the call from Toyota that the availability listing is a mistake. Super bummed because I’m trying way too hard to restore everything to how it was when it came off the production line. Exhaust will have to be a compromise so I’m open to recommendations from a anyone. Ordered the MagnaFlow 23894 cat so it will accept the temp probe but haven’t taken any other action yet

 

[Pitter Patter]

Almost guaranteed vacuum leak, spray the intake with carb clean while its running, this will locate the leak. If your exhaust leaks, you might as well do the much dreaded intake/exhaust gaskets!

Have a complete Toyota engine overhaul kit stashed away in the basement so good news is that I have those gaskets on hand. I did axles, drivelines, brakes, steering linkage and suspension this last summer. Engine/trans/t-case overhaul was planned for next summer when I was planning to do frame refurbish and body work. Guess the 40 is begging for more and doesn’t care about my timelines.

 

[AntFarm]

I will add to the opinion that you likely have vacuum leaks. I chased a bizarre high pitched whistling noise for a long time before I finally re-torqued my in/ex manifold and immediately fixed it. I need to re-torque the manifolds every few months to keep them tight. Since you have the late model emissions, also look at the various emissions hoses and fittings where vacuum leaks can be hidden. How's the condition of your plugs/wires/cap/timing? And finally, is the manifold heat riser flap working correctly? If you end up taking your manifolds off for a new gasket, look for cracks in the intake manifold there, which can also be a vacuum leak. Good luck.

 

[Pitter Patter]

Hey ceylonfj40nut, you were right that the OEM muffler is available. Just not through Toyota, since it is discontinued and they are out of stock. SOR has a stack of them so I placed an order for one. Way more expensive than direct but whatever.

I will report back on my findings/fixes once I get a chance to dig in if the weather is decent. Thanks to all for the advice.

 

[fj4075nc]

Hello Everyone, need a bit of diagnostics help here.
1981 FJ40, all stock except it is lacking the dual diaphragm vacuum advance but I'm not at altitude. Been doing a ton of work on it but not much under the hood. Things that have changed under the hood since I acquired it in late 2019: valve adjustment, air filter, belts, and timing gear cover. The vehicle has always suffered from difficult cold starts. Full choke, turns over a couple of times, catches and runs for a second then quickly dies, do it again and it will run. This has progressively gotten worse and on cold mornings it may take 3 or 4 repeats of this before it runs. It also needs to idle for a long time before you can start letting in the choke. Before the belts and timing gear cover, the high pitched squeal started so those changes shouldn't be a part of the problem.
Squeal happens intermittently during idle and while driving. Does not seem to have any relation to braking, clutch, throttle. It just comes and goes. This morning the stalling at idle happened while coming to stop signs was a major issue. It did this at every stop sign on the way to work but then after sitting for about 9-10 hours at work, it started great and drove great on the way home. The squeal seems to go away as the entire engine compartment warms. I posted a video of it idling and revving here:

This was from today after I got home from work.
This video:

Shows the difficulty of the hard starts, the overall engine noise and you can hear the squeal begin at about 1:06, this was from this morning.
Sincerely appreciate any input on helping chase this issue down.

 

[fj4075nc]

Hello Everyone, need a bit of diagnostics help here.

1981 FJ40, all stock except it is lacking the dual diaphragm vacuum advance but I'm not at altitude. Been doing a ton of work on it but not much under the hood. Things that have changed under the hood since I acquired it in late 2019: valve adjustment, air filter, belts, and timing gear cover. The vehicle has always suffered from difficult cold starts. Full choke, turns over a couple of times, catches and runs for a second then quickly dies, do it again and it will run. This has progressively gotten worse and on cold mornings it may take 3 or 4 repeats of this before it runs. It also needs to idle for a long time before you can start letting in the choke. Before the belts and timing gear cover, the high pitched squeal started so those changes shouldn't be a part of the problem.

Squeal happens intermittently during idle and while driving. Does not seem to have any relation to braking, clutch, throttle. It just comes and goes. This morning the stalling at idle happened while coming to stop signs was a major issue. It did this at every stop sign on the way to work but then after sitting for about 9-10 hours at work, it started great and drove great on the way home. The squeal seems to go away as the entire engine compartment warms. I posted a video of it idling and revving here:

This was from today after I got home from work.
This video:

Shows the difficulty of the hard starts, the overall engine noise and you can hear the squeal begin at about 1:06, this was from this morning.

Sincerely appreciate any input on helping chase this issue down.

See where you’re ordering a new catalytic converter, I have a brand new one never used never been installed for a 1980 FJ 40 will let you have it for half price plus shipping, I’m in Texas. There are a lot of converters out there to fit FJ 40 and different prices give me a reasonable price of what you’ve ordered and I’ll let you have half that thanks

 

[Pitter Patter]

Finally had some time to work on this and may have figured it out but now I have more questions. I did the check on the idle solenoid as recommended and it functions as it should. Carburetor was reasonably clean based upon a simple visual inspection and I can tell it has been take apart at some point because someone used philips screwdrivers on the JIS screws. I have to assume it was re-assembled correctly because the 40 ran well for over a year since purchase.

Temperature was in the low 50's today so I took this into consideration for my checks.

With the vehicle turned off, the choke cable / linkage worked well and fully closed the butterfly. I started the vehicle with full choke and noticed the butterfly was wide open. Discovered the choke opener diaphragm was under vacuum pressure causing the arm to contact the choke secondary linkage and force the butterfly open. I disconnected the vacuum hose that connects the choke opener diaphragm to the BVSV and the choke opener diaphragm lost vacuum causing the arm to fall away from the secondary choke opener linkage. So good news that the diaphragm works. Then I noticed the choke hadn't rotated back to the closed position. The choke linkage and outermost spring don't move freely so once the choke opener diaphragm kicked the butterfly open it was stuck open. This partially explains what's causing the hard starts. I'm assuming I have choke but I might actually not have any due to the choke opener system. What I'm really accomplishing with the choke is just creating fast idle but I'm not decreasing the volume of cold air entering the carburetor.

So here are the questions:
1. Should I lubricate this linkage? It's a bit better after cleaning but I can see how this would easily stick again simply due to metal to metal friction and the old spring.
2. The FSM says the BVSV should be closed creating no vacuum below 41 degrees and open by pulling intake manifold vacuum above 66 degrees. It was maybe 52 degrees today but it was always open upon cold start. Is this normal? Or is the BVSV potentially malfunctioning and stuck in the open position so I never have any choke?
3. While this may explain the hard cold starts, it doesn't appear to explain why it would die at idle when I get to a stop sign. Any recommendations for tracking this down? Fuel delivery seems good. It doesn't die making a racket or shuttering, the engine quickly loses rpm speed and stops.
4. Anything else I'm missing?

Thanks for the help

 

[whitey45]

Have you ruled out vacuum leaks?