Fuel Valve Identification - No Start Situation

[brianzero]

According to what youre all saying, the #2 cylinder should push on the governor handle in the clockwise direction. Here is a top down view of the #2 in the neutral position as the engine now sits, and the second image, extending the #2 cylinder rod full forward with locking pliers, and pushing the governor handle full forward.

Is this correct that the cylinder sits like this in the first picture? It makes NO contact with the governor handle without forcing it forward.

[freds]

Does it fire if you squirt in a bit of ether?

Is there someone near you that you can go take pictures of each connection to make sure you haven't reversed or omitted something?

Maybe simplify things by first running with a five gallon can at the rear of the engine.

Obviously you have done a lot things related to the fuel system and while you can flow fuel with a vacuum pump maybe there is too much restriction, etc. Any air bubbles while doing this?

[Coach_and_Crown_Guy]

So whats 3?

#3 is that throttle limiting air cylinder I was talking about. I didn't see it when I enlarged the jpg. Oops. Should have seen the slider bar at the bottom. It isn't required for normal operation and I'd remove/disable it entirely. Can't imagine any situation where you'd want or need to limit the drivers' throttle pedal travel. It's just another engineered complication add-on that has the potential to fail and screw things up. Simpler is always better.

[Coach_and_Crown_Guy]

According to what youre all saying, the #2 cylinder should push on the governor handle in the clockwise direction. Here is a top down view of the #2 in the neutral position as the engine now sits, and the second image, extending the #2 cylinder rod full forward with locking pliers, and pushing the governor handle full forward.

Is this correct that the cylinder sits like this in the first picture? It makes NO contact with the governor handle without forcing it forward.

NO.

You have it backwards. #2 is an air actuator cylinder that is ONLY pressurized and pushes against the shutdown lever when you shut the engine off. The shutdown lever itself is in RUN when it's fully counterclockwise. STOP is when it's fully clockwise.

When you start the bus normally AND it has air pressure already built up, the electric Skinner valve is energized when you hit the stop/run switch in front. You Should hear a momentary pop of released compressed air. This small amount of released air is from the stop lever cylinder #2 and it's air lines. So when the engine is running, the stop cylinder has NO air pressure therefore it's retracted fully. When you hit the switch to stop the engine up front (or rear), it de-energizes the Skinner electrical solenoid, whereupon it switches the air pressure to the stop lever cylinder and it pushes on the stop lever to shut the engine down. Skinner valves are available in many air pressure port configurations. The air lines are attached so that when UN-engergized the air line from the STOP cylinder is being supplied with bus air pressure. When energized it vents the air from the STOP cylinder and lets it retract, this allows the engine to start. Clear yet? It's reverse logic I know but that's how it works. Wait until you experience the fun of starting the bus with no built up air pressure. You can immediately shut the switch off to stop the engine..... but nothing will happen and it will continue to run.... until enough air pressure builds up to push the STOP cylinder to move the shutoff lever to stop position.

In emergencies I've always just removed the stop lever air cylinder and driven the bus to get it repaired. Knowing how this system works from the electrical to the air lines is not difficult and can save a whole lot of headaches if it happens on the road somewhere in the middle of nowhere at O'dark-thirty. That's why I suggest you remove it for now until you find what's keeping it from starting.

With no air in the bus the STOP lever is normally in the RUN position and the internal fuel racks are at FULL fuel. In a word the engine is a loaded gun and WILL start if the crankshaft is turned. Once it spins up the Governor takes control and holds it a low idle. It requires at least 90 psi air pressure for the stop cylinder to push the STOP lever hard enough to shut it down. Until that happens you can still reach in and move the stop lever Clockwise Hard and HOLD it there until the engine stops.

Being a turbo-6V92 it shouldn't have an emergency shutdown damper on the air intake,... but you never know. I'd look around anyway and verify it's doesn't really have one. If all this is in good order you may indeed have a fuel system issue after all.

Since you have the Allison, which is also the usual setup for that era, I'd leave that throttle #3 limiting air cylinder alone and let it do it's designed thing, whatever that is. The Allison has several tie-ins to the engine and that may be one of the required air actuators to keep things from damaging the Allison.

A DD 2-stoke engine only requires three things to run. Air, Fuel, and high enough compression in the cylinder to ignite the fuel, period. Very simple. Just like making money on the stock market, buy low and sell high, right? Simple. Keep at it and you'll figure it out.

It may also be time to call in a qualified Detroit 2-stroke mechanic to help you get it back on its feet. If you mess around too much and change or alter things you likely make it worse and run the $bill up when you finally do call a mechanic in. Finding experienced and capable 2-stroke mechanics today is getting very hard, and I'm not being funny, it can be Damned hard. I'd check around your area for Charter Companies who have been around long enough to have had and used DD 2-stroke engines, Series 50-60 4-storkes don't count, then maybe you can scare up a mechanic who can help you out. A retired grey hair is also someone to try and find. They usually enjoy the chance to work on the DD's again. Another place to check is Marine Engine Large Boat places. Also Truck companies, Oil field companies, and stationary generator installations still use lots of DD 2-stokes and should have access to qualified and experienced mechanics. Good luck and anything you find will come in handy later as you will be needing the help again for sure.

Many places will shy away from working on a bus because they don't know them or want the hassle of learning. That's why a local bus company is a good place to start. The engines themselves are all the same but the various modifications for the different applications are what will give non-bus experienced mechanics or shops the Willys. Keep looking and persevere and you'll find the help you need. Maybe a good mobile mechanic who does work on the older buses is around your area. By the way, where are you located??

A mechanical DD 2-stroke is a wonderful engine and very reliable and easy to work on. They are simple, reliable, all mechanical with no computers or electrical complications, except the Skinner valve used for shutdown. They're used in some other functions in the bus as well, like the fast idle cylinder needs one.

The MCI manual will help you with that. Once you have learned enough to understand how they work and how to keep them running you can confidently take them anywhere you want and feel assured you can get it home. It's worth it to learn about the engine and it's systems and the bus systems as well. I'd also encourage you to take the time to learn the correct nomenclature for describing the various parts and operational systems as you encounter them. This will make it much easier to describe your difficulties to the folks who will be trying to help you out of your jam and remove the miscommunications and misunderstandings that incomplete descriptions can create.

[lovetofix]

I have the same governor setup on mine.
On the throttle limiting air cylinder. It should extend (stop the throttle lever from moving) when the high idle is engaged. I believe this is to keep you from trying to drive with high idle on which I believe could damage the automatic transmission as well as create a dangerous situation when you try and stop.
The high idle cylinder advance the fuel control rods inside the governor housing (through the buffer switch if you have Jakes) and the throttle limiting cylinder prevents you from giving throttle input through the accelerator peddle/throttle lever.
I would definitely leave it in place.

[brianzero]

Just a quick update that will help somebody in the future, I got the engine to start and run just fine (after 5 years of sitting). I disconnected the air cylinder for the stop valve, and it started right up. I was able to easily stop the engine by pushing the stop lever on top of the governor body.

[Coach_and_Crown_Guy]

There 'ya go. That's the field expedient work around to use when all else fails to
isolate the problem, probably electrical in nature. Now you should be
concentrating on running down the cause of the shutdown lever actuating
cylinder getting air and not releasing as it should to allow the shutdown
lever to move to the run position. Like I said it's most likely an electrical
problem in the circuit controlling the shutdown actuator. One question I have
is whether or not the cylinder is retracted all the way back with no air pressure
on the bus. It's totally normal for the bus to start with no air pressure due to
the actuator being retracted and not contacting the shutdown lever. Then when
air builds to about 90psi it will have enough pressure to push the stop lever
and shut the engine down.

One of the patented "fun with Detroit's shutdowns" is to start the bus with no
air in system then immediately turn the electrical ignition switch to stop and see
how the engine continues to run at idle.... You can leave the bus and walk away
and wait for the air pressure to build up enough to slowly choke the engine to
stop as the actuator pushes on stop lever. This too is normal behavior on the
air actuated stop/run system. Many people panic when it first happens to them
but once I explain how the system works they finally understand. Air pressure
actuators control several of the engine functions, Shutdown, Fast Idle, Throttle
interlock against driving with fast idle engaged, and probably also when parking
brake is set.

Can you explain how, with no air pressure on the bus, the shutdown actuator
was able to push on the stop lever?? Am I missing something in your posts?
That shouldn't happen, (with no air), unless there is a mechanical issue where
the actuator when fully retracted isn't disengaging from the stop lever and letting
it return to the run position. It's possible that the actuator isn't the correct
one with wrong retract/extended specifications, though I can't see how, since
the bus obviously was working OK (I'm assuming) before your problem. As long
as it retracts enough to come off the stop lever at it's run position, then all
should be fine. I'm a tad paranoid I guess.

I'd suggest reading the manuals, both the MCI manuals and Detroit engine manuals.
Get educated on the way things function and why. This will pay enormous dividends
if you ever need to find a work around to get yourself off the side of a road somewhere
in the middle of the night. You actually achieved that goal with what you did by removing
the actuator. Knowledge is Power, Safety, Control, Security, and most of all saving
many $$$$ by doing things for yourself. Don't expect too many "Mechanics" to be
able to help you out. VERY very few have a clue about anything Coach related, you'll
find this out more in due time. You really must be your own Knowledge base on your
chosen bus.

As an aside I'd say that with more experience you're going to find that the pure
mechanical, versus DDEC computerized controls, Detroit engines are, for me at
least, much more desirable. Less complicated, no computers, once set up they run
well for many, many miles, and usually easier to troubleshoot and repair in the event.
Learn all you can and you'll come to appreciate the many virtues of these engines.

And be sure to use the correct straight 40wt CF2 engine oil, and drive it like you're
mad at it and keep your rpms up close to the governed speed as much as possible.
Watch the temp gauge and don't hesitate to take control and downshift manually if
it feels like it's trying to get hot. Don't lug it at less than about 1700 rpm for very
long, downshift if it's not picking up speed, that's how you drive them, or else you
risk breaking it and incurring truly frightening repair costs. These are the main points
in how to get the most out of your DD 2-stroke engine. Always watch the temp
gauge, plus it's a good idea to check it out to make sure it's accurate and working
correctly, very important and worthwhile to protect the engine, or else $$$.

If you want to contact me direct for more details feel free. There's more to relate if
you want to get the most out of it, too much for here.

[luvrbus]

So whats 3?

Number 3 is a clamping cylinder to prevent the engine from running away when the fast idle is turned on it locks the governor in place ,# 1 and #3 are plumbed together all DD are plumbed that way not only MCI 

[luvrbus]

#3 is that throttle limiting air cylinder I was talking about. I didn't see it when I enlarged the jpg. Oops. Should have seen the slider bar at the bottom. It isn't required for normal operation and I'd remove/disable it entirely. Can't imagine any situation where you'd want or need to limit the drivers' throttle pedal travel. It's just another engineered complication add-on that has the potential to fail and screw things up. Simpler is always better.

He better not remove # 3 and turn on the fast idle unless he wants a underwear change ,you are giving the guy some bad info that cylinder is part of the fast idle

[brianzero]

This is just an observation, in my situation, that #3 cylinder stands in the way of a full throttle movement. If I remove that #3 cylinder, I can have full throttle available to me. With the #3 installed, I have maybe 60% throttle available. I removed #3 for test purposes, and the bus is far better and very responsive!

[luvrbus]

If you remove # 3 then remove the fast idle cylinder from the buffer location on the governor  and plug the air lines and install a buffer screw,you are in a area that can cost you a engine if not careful,if you have a DD manual with all pages it shows you how to adjust the clamping cylinder on the fast idle 

[Busted Knuckle]

This is just an observation, in my situation, that #3 cylinder stands in the way of a full throttle movement. If I remove that #3 cylinder, I can have full throttle available to me. With the #3 installed, I have maybe 60% throttle available. I removed #3 for test purposes, and the bus is far better and very responsive!

Listen to Clifford!

He better not remove # 3 and turn on the fast idle unless he wants a underwear change ,you are giving the guy some bad info that cylinder is part of the fast idle

He is correct #3 is to keep high idle from over revving and casusing a "run-away scenario"
Clifford won't steer ya wrong, he is the YODA of Detroit 2 Strokes and most things bus related! He's probably forgotten more than any of us will ever know in the first place, but he still knows what he is talking about.
If #3 is limiting your full throttle, most likely your fast idle is engaged!
  BK   

[luvrbus]

If he just follows the air lines he can see #3 is plumbed into the fast idle cylinder to work together

[brianzero]

Listen to Clifford!
He is correct #3 is to keep high idle from over revving and casusing a "run-away scenario"
Clifford won't steer ya wrong, he is the YODA of Detroit 2 Strokes and most things bus related! He's probably forgotten more than any of us will ever know in the first place, but he still knows what he is talking about.
If #3 is limiting your full throttle, most likely your fast idle is engaged!
  BK 

My high idle works just fine, and before I drive, I disengage it. Now, the question is because the high idle works and keeps the motor RPMs where it should be, if I adjust its position, it probably wouldnt be running at the higher RPMs, and would definitely be lower. I suppose something is wrong with the air cylinder, and that the throttle lever should be able to easily push it in, overcoming the spring inside of #3?

[Coach_and_Crown_Guy]

Listen to Clifford!
He is correct #3 is to keep high idle from over revving and casusing a "run-away scenario"
Clifford won't steer ya wrong, he is the YODA of Detroit 2 Strokes and most things bus related! He's probably forgotten more than any of us will ever know in the first place, but he still knows what he is talking about.
If #3 is limiting your full throttle, most likely your fast idle is engaged!
  BK 

OOOPs. My Bad. I stand corrected and admit I was wrong on my advice. I was thinking the
Fast Idle cylinder acted alone in advancing/overriding the Low Idle setting to the High idle setting, which is what it does, and it's adjustable you should know, but hadn't realized that the Fast Idle Limiting Cylinder was also in play to limit the throttle lever from advancing as well. This has a secondary benefit of sending the driver a clear signal that the throttle isn't working and he should look to see that the fast idle is on. I've been there plenty of times myself.

This feature was used on all the DD V-XX's going back to the 4106 as soon as they designed in the air actuated fast idle cylinder into the Governor. The fast idle was needed for the A/C system for running the compressor at a good speed as well as the alternator to keep the batteries charged as the interior DC voltage blowers drew an awesome amount of current. The V8 engines were powerful enough after the straight 6-71's used on the 4104, and before, to have enough excess power after propulsion to power the A/C directly off the main engine, instead of needing the separate pony engine as used in the 4104 etc.

I jumped to a hasty and faulty conclusion with incomplete information and I "Assumed", thus my response. We all know what "Assumed" makes of me, right? I didn't realize, until I checked my own manuals just now, that the limiting (clamping) cylinder was used in all of these installations from the very beginning of the air powered Fast Idle feature.  Again my mistake and I stand corrected.

If you are only getting 60% throttle with the Clamping cylinder in place it most likely is a matter of something being out of adjustment with the several moveable items in that area. Take the time and do a thorough check that all the items are moving the full distance they should and that nothing is getting in the way to limit the full fuel travel of the Throttle lever. It's not an uncommon problem for various mechanical issues to crop up that will limit the full travel to full fuel position of the Throttle lever. This is true of any brand of bus and installation. It's one of the first things to check if the bus feels like it isn't accelerating very well, or it has trouble maintaining road speed, or drops off fast when starting up a grade. Make sure for real that the linkages are really doing full fuel on the Throttle lever on the governor itself. The Manual should give information on the proper adjustments and the order in which to check them.