Hello again folks , as some followed my bringing her home finally thread know . I was having some issues with it settling to one side overnight and not staying running past 30 pounds of air pressure when I try to crank her the following morning.
I aired her up three times three separate occasions once it is that full 120 pounds she started right up and stayed cranked.
She's been sitting for 3 weeks, assuming nothing has changed should be able to do the same... until I figure out what the reasoning behind all of this is, my question is.... should I get air compressor with a higher tank volume/ cfm? or a portable air tank that will fill her up ? My thoughts were getting adapter for one of my scuba tanks that will hold 3000 pounds plus and I could feel her up a few dozen times need be?
Shooting in the dark here guys any help is appreciated.What I do know..... Figure out why she's leaking air and then figure how the inability for her to stay running is related.
Information I know , she ran like a top for 16 hundred miles. Oil pressure was questionable due to faulty gauges no problems starting her other than when she's air down or leaning . She's been sitting for 3 weeks on relatively level ground maybe a little lower in the rear. And she still would not stay running for more than 30 pounds . Oil dipstick still reads full.
Thanks for reading!
So, to clarify....
You're saying that it will start with zero air, but will only run till air pressure gets to 30 psi and then it will shut off.
But if you air up to 120 psi from shop air, it will start and continue to run without shutting off.
Is that correct?
That is correct Craig.
Check the rear shutoff switch it may be in the off position. What confuses me is the is the fact it will run fully aired up which it shouldn't if the switch is off. I would check that switch first to be sure it is on.
John
Well, I'm stumped, but I'm going to suggest that as you air it up, try starting it at intervals of 10 psi. I suspect at some point, it will stay running. Probably sooner than 120 psi. Maybe that will give us a clue. The air system does different things at different pressures.
It's a shot in the dark.
I don't believe it's related to the angle of the bus from deflated air bags. I suspect it's related to a pressure device, though I'm not aware of one on the shutdown system that would
cause this kind of behavior.
Its either a check valve or the air drier if you have an AD2 still. Are you airing it up with the shop compressor in the back or in the front. If it is in the front it will by pass the air drier and it should air up all the way. If you air it up at the back it all goes out at the first opportunity which would be the purge valve on AD. Yes NO
When the engine and its compressor is running it first goes to the AD and will not build if it is opened or the check valve is stuck opened. See if there is a leak about center on the front wall of the front wheel well. Don't go under unless it is blocked up just listen up there.
Dave5Cs
Quote from: Dave5Cs on May 09, 2016, 08:54:01 PM
Its either a check valve or the air drier if you have an AD@ still. Are you airing it up with the shop compressor in the back or in the front. If it is in the front it will by pass the air drier and it should air up all the way. If you air it up at the back it all goes out at the first opportunity which would be the purge valve on AD. Yes NO
When the engine and its compressor is running it first goes to the AD and will not build if it is opened or the check valve is stuck opened. See if there is a leak about center on the front wall of the front wheel well. Don't go under unless it is blocked up just listen up there.
Dave5Cs
The problem is not that it won't air up.
The problem is that it won't stay running unless the system is aired up first.
If he starts the bus with no air in the system, it will only run until the air builds to 30 psi. Then it shuts off. This initially would lead me to think the rear shutdown stop/run switch is in the stop position, as John mentioned above. However, Lou says that if he airs the system up to 120 psi using shop air before he starts the bus, it will continue to run just fine. This would contradict the stop/run switch being in the stop position.
I working on where he said there was a leak which I was premature on. Sorry But
I understand that part,LOL I guess I was trying to figure out where he was airing up the system with the shop air so that we might see something in that line that was allowing it to not stop and we know where the air comes from the bus compressor to air up to only 30PSI and then shuts down. These are two different places and one would have nothing to do with the other being the 30 and shut down and the 120 and no shut down because it may be past the shutdown switch. I know I am not making sense but it was that we were putting them both in the same order and it is not. :)
Dave5Cs
Craig how about if he take the air fitting off the back of the shut off valve and then start it and see if it build and stays running. If he needs to turn it off just put it back on and pull on and hold the shaft to stop the engine.
Dave
I think I may have the answer to this. Or at least a plausible theory...
I believe the skinner valve that controls the shutoff cylinder is sticking in the open position.
In order to shut off the bus normally, air is applied to the shutoff valve by cutting the power on the skinner valve which opens and allows air to flow to the shutoff cylinder.
The skinner valve is normally open. It requires power to hold it closed and not activate the shutdown cylinder. The master switch is turned on, power is applied and the
skinner valve closes, which cuts off air to the shutoff cylinder. If it were sticky, it may not close when power is applied until enough pressure builds up to force it open.
As pressure builds to 30 psi, with the valve still not closed, the shutdown cylinder is activated. This is the symptoms of the stop/run switch being in the stop position.
By pressurizing the system first, there is higher pressure on the valve, which helps overcome the stickiness and pushes it closed when power is applied.
Ok, shoot holes in the theory.
Quote from: Dave5Cs on May 09, 2016, 09:32:15 PM
Craig how about if he take the air fitting off the back of the shut valve and then start it and see if it build and stays running. If he needs to turn it off just put it back on and pull on and hold the shaft to stop the engine.
Dave
He could do that. Might have to plug it some or it might not build air.
This might also help validate my above theory. If the air is plowing out the supply tube as it airs up, and then stops as pressure builds up somewhere past 30 psi, it would indicate
the skinner valve is indeed sticking.
Quick and dirty, let's eliminate the symptom, then work on the cause?
Remove the two screws on the engine shut down piston, and let it hang away from the stop lever.
Start bus, and observe the behaviour of the piston.
Who has a picture to help point out the thing to remove?
If theories about sticky stuff are correct, the piston will poke out as pressure builds, and then retract when whatever unsticks?
First, let's get the bus engine running consistently, then we'll try trouble shooting?
happy coaching!
buswarrior
Wow! It feels like I just went to a meeting with engineers, and not the kind that drivetrain is LOL!
But I do comprehend the theorys you all speak of .
I will not be back in New Hampshire till as early as early as this coming Saturday morning but may not be back until the following weekend.
Just to confirm I did check the rear shut off switch As I accidentally hit it on my trip and when I went to start her back up there was no engaging sounds of the starter.
And yes I'm a big fan of pictures because I wouldn't even know where to start!
I am airing it up from the front of the bus does have a what I believe is a check valve off and on before the nipple
Breif Point,the compressor that I have I have to stop the flow of air when it balances out from the compressor to the bus then let the pressure build up well past 120 pounds on the compressor and then release more air. Have to do this multiple times to get it up to at least a hundred or so. What are other better options? A bigger compressor that I would want to haul around with me just in case :-) or a large cylinder of compressed air that would not rely on electricity to run. Just need to keep that question alive in the thread.
Thanks again Gents! Keeps me in the know and nothing like being educated!
To clarify, if you have a shutdown lever that's air operated (and I think you do) it won't stop the starter from turning. It merely stops fuel...so what you're talking about is the rear engine start switch, what everyone else here is talking about isn't a switch, it's an actual mini air piston that pushes a lever to shut your engine down. Here's a pic of one:
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fuploads.tapatalk-cdn.com%2F20160510%2F1ed817a260ff0683437eb0678a7d38fd.jpg&hash=a85a3e3b164ff79be455e8b41d66e88b610a7a67)
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BW is right on his idea of confirmation. You can loosen the screws on the shutoff cylinder, remove one and twist it away from the shutoff lever and try running
the engine up to full air, while watching the cylinder behavior.
As for shop air input, the best location is typically in the right rear engine access door. There's usually an air drain there with a quarter turn valve. You can add a male
air fitting to the drain line and just chuck your compressor in there. You should be able to run the compressor from 0 up until 120 psi. At that point, the air dryer
will blow off and will continue to blow air until you shut off the quarter turn valve where the compressor is connected.
Here's some photos of the engine stop cylinder:
Lol Craig and I posted at the same time. That should be your issue. I'm almost sure it is....
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Yep and thats why I was asking where he was airing up with the shop air. Also if it was having a problem or does still from the rear then you have a stuck check valve up front also. But move the Skinner valve first to see if it is moving its shaft. If not try moving it by hand and lube it up if needed then see if it works better.
Dave5Cs
you can certainly observe it's function without removing any screws... ???
But the experiment won't proceed if it shuts the engine down as 30 lbs approaches?
The sense of satisfaction of the engine finally continuing to run might be needed for morale purposes?
happy coaching!
buswarrior
The Skinner Valve gets my vote. It seems to be one of the most troublesome parts of any bus that has them.
Quote from: buswarrior on May 10, 2016, 09:58:09 AM
But the experiment won't proceed if it shuts the engine down as 30 lbs approaches?
The sense of satisfaction of the engine finally continuing to run might be needed for morale purposes?
happy coaching!
buswarrior
oh... ;D
I've detailed my theory. I think it's the only plausible explanation for the symptoms indicated.
I feel others may have differing views, and may even be confusing the individual components involved.
I'm bowing out of this discussion until more information is known.
Lou, feel free to call me or email me if you need more information or guidance on how to diagnose this problem.
craig
One final...
I sent this problem to a bus mechanic friend of mine who knows more about buses than any of us will ever acquire. He's the guy I trust with my bus and the guy I go to for
all problems I can't solve. He confirms my diagnosis of a bad skinner valve based on the symptoms provided.
Good luck, Lou. Email me if you need or info.
craig
and now we wait... any updates ?
He won't be back at his bus until next week
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Wow! And I thought my head was spinning from my career change ! Until I read the replies I didn't know what a Skinner valve was. haven't put my hands on one but thanks for the pictures and the detailed information that everyone gave me I see no problems finding it and problem solving it. Scott, Dave ,Donald ,Walter, Bus warrior and anyone that's contributed to the thread I can't remember:-) thank you very much for all of your input. I am really chomping at the bit to get back to New Hampshire now to investigate and solve this problem. If I haven't mentioned it within this thread I have decided to move the bus 200 miles to the Syracuse New York area to reside in it until I find a place but feels right for me.
Wasn't planning on going back to the New Hampshire till next weekend but it's only a three and a half hour drive from where I will be Friday evening so I may surprise attack just to put my mind at ease and figure out what's happening. Thanks again to all of you !!! I will post immediately when I return.
Hmm... Thinking maybe we left out one important detail. The above photos are not of the Skinner valve, which is probably the culprit. They are of the air cylinder
that actuates the fuel shutoff. There's another right next to it that controls the fast idle.
The Skinner valves are the electric valves typically located on the firewall that control the air flow to those cylinders. I'll attach a photo.
Locate the shutoff cylinder using the above photos, and then follow the air line back to the electric valve to determine which one is the problem. It will have air lines
coming in and out (whereas the cylinder only has one coming into it), and electric wires attached to it.
He can't miss it now!
Quote from: DoubleEagle on May 11, 2016, 08:24:58 PM
He can't miss it now!
the acting cylinder is called a clamping cylinder...trace/follow the airline. it ends/starts at the skinner valve :)
Clear as mud now? 😳 welcome to the madness 😩
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You have photos of your system ? you may have the Kysor system we went through this on the BNO not long along
Quote from: luvrbus on May 12, 2016, 10:53:58 AM
You have photos of your system ? you may have the Kysor system we went through this on the BNO not long along
which presents more difficult trouble shooting quandaries :(
Hey guys, I was able to briefly run by there and take pictures and find the things that you all were so generous to post pictures of and here are the pictures of mine. Thinking this past week it did not have this particular issue until the first night I took her on the road. The only thing that changed from days past when she cries any time at any level was the high pressure steam cleaning of engine 1 hour before I left Florida on my trip back. Now tell me, what relationship does that have with the new issue we are working on? If any?
So it looks like the rear Skinner valve and picture is original or much older than the front one that has electrical wires coming into it so I'm guessing that is the valve to replace? Or am I understanding it wrong? Either way where would I procure one of these wonderful solenoid Skinner valves?
i seriously doubt that the skinner valve is your problem. having said that, those skinner valves are proprietary as in plug and play... finding ones that simply plug into those connections...won't be easy.
observing them is going to be your best bet to understand them...
it is a simple plunge action to extend that rod to shut off the motor and a spring inside assists it to it's resting position to prep it for it's next use...
Ok, so what you have there is a Skinner valve attached directly to the control cylinder. The one on the left in the photo, which is silver and appears to be attached directly to the cylinder
with a piece of rigid pipe is the fuel shutdown. That lever which the plunger is pointing at is the shutdown lever. Incidentally, this is the lever you would push with your thumb should you ever need to shut down the engine manually, such as before the air pressure has built up. This cylinder is the one you want to be watching as your air pressure goes up. It should stay retracted as it is in the photo. If it pushes out and pushes on the shutdown lever at say 30 psi (which is where you've indicated your bus shuts down), then the electric Skinner valve behind it is probably sticking and needs to be replaced. They are interchangeable, you'll just need to find a replacement. They can be rebuilt, but they require some special tools to take them apart.
The electric Skinner valve in the back, the one with the green tinge to it, is attached to the fast idle cylinder which is the right hand cylinder in the second photo. That one is not part of this problem. Ignore it.
As for the high pressure steam cleaning, you could very easily have forced moisture into either the Skinner valve assembly. There's a mechanical plunger in that valve body and moisture in there could make it stick.
You could try removing the air lines from the Skinner valve and squirting some light oil in there. Many tout Marvel Mystery Oil. I have no experience with that. I would probably squirt a shot WD-40 in it to clean it, and then maybe a squirt of ATF or 10W to lubricate it.
^ read this carefully and slowly and you'll be able to rule out or confirm the engine stop cylinder as the issue.
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Video of me pushing my shut down cylinder. Hit play even if it says video not available. It works.
https://vimeo.com/166966362 (https://vimeo.com/166966362)
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Craig, I understand completely your explanation thank you very very much! Along with Scott's video, Thanks !! I believe I am armed with the information to determine or rule out the Skinner valves part in my issue. I'll be back in New Hampshire Friday evening and am looking forward to at figuring it out. I was able to air it up manually from underneath the driver side compartment. And she started just fine after 60 pounds or so.
I will keep you posted when I have more info, currently in Plattsburgh New York.
Thanks again gentlemen!
Well, finaly got time to check her out and heres what I did....
Took air lines off both sides of front Skinner valve then backed the T off the top and shot a blast of WD40 then closed her up. Started her up and about 25 lbs the valve slowly came out then shut her down as in the past.
My question is can/should I hold the shaft/cylinder back
Long enough to build air pressure and if so will it retrack?
OK ... seems like the Skinner valve needs to be replaced/rebuil and im ok with that but presuming I can't/don't have tine and am stuck without shop air ,can I hold the shaft back long enough to keep her running?
Seem if air is high enough the shaft will not push out and assuming when pressure is high enough it will retrack?
Just thinking out side the box I .
Thanks gents!!!
Picture of cylinder at 30 lbs.
When I start my eagle from the back and don't get up front to
Turn on the switch it will die from lack of curet to the valve that
Controls the plunger that kills the engine, that is how it is suppose
to work. I would check voltage to that valve or for proper operation.
I never checked the pressure when it dies but would think it would
not take much. Good luck, Bob
Bob has a good point there. The Skinner valve requires power to keep it closed. When power is cut (i.e. the master switch is shut off), then the valve automatically opens, allowing air to flow to the shutdown cylinder and push the fuel shutoff lever.
Before you start it, and with no air in the system, you should test the voltage at the electrical connector. If there is none, then the valve cannot close, and the result would be exactly as you experienced. This leads back to the safety shutdown system, as mentioned early in this thread. If per chance there is something else telling the system to shut down (e.g. oil pressure, water temperature, water level, etc), that could be causing these symptoms, though off hand, I can't come up with a scenario that would indicate one of these other sensors.
My money is still on the Skinner valve, but I'd also suggest you swap the two Skinner valves (shutdown and high idle) to verify the one is bad. If the problem persists, then it's not the Skinner.
As for starting it, as you asked, you probably won't be able to hold the plunger back with your thumb or fingers. You might be able to use a quick clamp, such as used for woodworking, and hold it back. Otherwise, remove the two screws holding the plunger cylinder down, and the screws holding the Skinner to the plate and you should be able to move the assembly out of the line of fire for the shutdown lever. Not very convenient, but in a pinch...
craig
Cool, now you're on the right track and are chasing down something likely fairly simple
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Thanks again guys! I was able to get over to her late on Sunday and experiment with the skinner valve and holding the cylinder back from pushing the shut-off. I could not get anything to hold such as C clamps or trigger clamps so I just took some 14 gauge electrical wire single strand with shroud around it and wrapped it around the steel brackets on the other side of the Skinner valve and then wrapped around the shut-off. Then just took a pair of pliers and twisted the tension to tighten it like you would rebar ties . cranked her up . The plunger did come out h
At about 30 pounds but could not push the shut off switch, aired up no problems then went true engine and cylinder had retracted remove the wire she continued to run no problems. I will be taking her to her summer resting place at Oneida Lake just north of Syracuse. On Saturday. Then I will have time to figure out the Skinner valves this summer. I will keep you all posted on my travels to Syracuse. Thanks again and have a great Memorial Day weekend!
So to shut down you're reaching in there and pushing the lever right now?
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Quote from: Scott Bennett on May 25, 2016, 03:08:22 PM
So to shut down you're reaching in there and pushing the lever right now?
No. It shut down just fine. It wasn't running on startup after 30 lbs. He's prevented the shutdown cylinder from activating the rack fuel shutoff lever until it gets fully aired up, and then
removing the wire he used to hold it. After it's aired up, it starts normally, runs normally, and shuts down normally.
sounds like it's wired backwards...so that the coil is not closed on the key switch or a bad relay.
Quote from: eagle19952 on May 25, 2016, 08:32:13 PM
sounds like it's wired backwards...so that the coil is not closed on the key switch or a bad relay.
No. It's not wired backwards. It's either a bad Skinner valve (most likely), or it's a bad sensor in the shutdown system.
Quote from: gumpy on May 26, 2016, 06:42:01 AM
No. It's not wired backwards. It's either a bad Skinner valve (most likely), or it's a bad sensor in the shutdown system.
time will tell. i did say bad relay. and backwards meaning improperly also...
Quote from: eagle19952 on May 26, 2016, 08:55:57 AM
time will tell. i did say bad relay. and backwards meaning improperly also...
Well, here's the thing. He was driving it down the road just fine one day, and the next morning, it wouldn't stay running. The difference was he pulled over for the night. Now, I'm not saying some road gremlin didn't get in there while he was traveling and rewire that Skinner, but I think it's unlikely. I suppose there's a scenario where a broken, or breaking wire could cause the symptoms. I don't think they'd necessarily be repeatable as his are.
Not completely discounting the bad relay idea, either, since there is one in the shutdown system, but I can't come up with any scenario where a bad relay would produce the symptoms he's experiencing. If the relay were stuck on startup, it might certainly cause it to shutdown when it airs up to 30 psi. However, there's not a solution for the problem going away when he gets fully aired up. If the relay were stuck, it would still be stuck at 120 psi, also, causing a shutdown.
Considering he said they washed the motor just before leaving FL, I'm sticking with the moisture in the Skinner valve theory, which is causing it to stick open, or partially open, until enough air pressure builds in the system to force it to close.
Quote from: gumpy on May 26, 2016, 08:37:01 PM
Considering he said they washed the motor just before leaving FL, I'm sticking with the moisture in the Skinner valve theory, which is causing it to stick open, or partially open, until enough air pressure builds in the system to force it to close.
Excellent logic, and given the history of Skinner Valves and their ability to cause grief, I agree totally.
Could you pull air line off and drop 2or3 drops of air tool oil in it/or line then reconnect? I have done this in other parts of air system with good results. I agree it sure functioned until it sit for awhile.