I took my bus out this weekend for a nice cruise to Ohio, and on my way back I stopped at a gas station, filled up, and then started to drive away. I got a few feet from the pumps and my engine quit running. I could not get it started again. I know I didn't run it out of diesel. I was only about 20 miles away from home, Soo Close! which I then incurred a hefty towing bill. I have a GMC 4905 with a Detroit 8v71. any suggestions, or things I could test would be very appreciated! I also tried to start it this morning and I ran for a few seconds, and then died again.
thanks,
Chris
If you fueled up with the engine running I would say you sucked trash into the lines.
Change both filters,fill them up with diesel. may have to take the line loose infront of the check valve and blow it out.
Don't ask me how i know all this.
ned
Ned,
thanks for the info. I didn't know you could do that by filling up with the engine running. I've done that many times.
Is the check valve up front near the tank or back by the filters?
Chris
Smell of the diesel. If it smell like gasoline , it is. We have this problem often in the Tractor repair business. Also, look at your reciept. Does it list diesel or unleaded. Sometimes the pumps do not switch. If it's gas, drain and refill everything.
Thats interesting, I sent my son in law to a staion with a gas can for some diesel, he came back with gas in it and insisted it came from the diesel nozzle, is it possible it didn't switch? I just blamed it on a bone headed kid, maybe it wasn't his fault, I don't know.
I will definately check that! The pump was only a diesel pump. It didn't have any other fuel selections, but there is a chance. You never know. I Hope not!
Cody, I do not know if he is a bonehead or not. If he is , he will grow out of it . I have seen several times the pumps that dispense gas and diesel not switch. I have also seen gasoline unloaded into diesel tanks, but usually the driver will catch pretty quick.
That's one reason I despise those combo pumps and avoid them if I can. Just one more thing that can go wrong. And Murphy (Murphy's Law) is all too familiar to busnuts.
(Side note: Imagine another scenario that can happen with the combo pumps. Somebody buys diesel from the pump. The next person to use it is somebody filling a 1 gallon gas can for their lawn mower or for their out-of-gas car. That hose holds 1/2 gallon of fuel. So they get 50/50 gasoline and diesel.)
We always fill our bus at the truck pumps. No gasoline pumps here, all diesel. Also, they are the larger diameter nozzles, so we can pump 125 gallon much quicker. Jack
My education continues, I didn't know that, I'll watch and check from now on, (my son in law is a bone head, that I do know lol, like you say, maybe he'll grow out of it) lol. The pumps I normally use up here are the truck island pumps and there arn't any gas pumps close to them but from time to time I use pumps that have 2 or 3 gas nozzles and a diesel nozzle on the same island. I'll be carefull with these.
Quote from: chriss on September 15, 2008, 01:10:01 PM
I took my bus out this weekend for a nice cruise to Ohio, and on my way back I stopped at a gas station, filled up, and then started to drive away. I got a few feet from the pumps and my engine quit running. I could not get it started again. I know I didn't run it out of diesel. I was only about 20 miles away from home, Soo Close! which I then incurred a hefty towing bill. I have a GMC 4905 with a Detroit 8v71. any suggestions, or things I could test would be very appreciated! I also tried to start it this morning and I ran for a few seconds, and then died again.
thanks,
Chris
Hi Chris,
Smell the fuel tank. Does it smell like diesel or gas? If diesel,
Your filters could be clogged or you developed a leak and sucked in air. When was the last time you replaced the filters?
Try what Uncle Ned told you and let us know
Nick-
Hello Nick!
I just replaced the fuel filters 2 weeks ago. I'll try taking one off and smell the fuel to see if it smells like gas.
Where are these combo pumps? I've driven from AR to the west coast four or five times, to the Gulf Coast numerous times and to the east coast just last June, and on none of these trips have I ever seen a nozzle that dispensed both diesel and gas?? Most stations I've used even have the dieselpump sitting away from the other pumps.
The only time I almost goofed was one station that had a green nozzle that dispensed gas, only time I ever saw green for gas. I now remember the brand, BP, but I did pump a gallon or two of gas before I caught it. Even that one was not a combo setup, the diesel nozzle was black??
Quote from: gus on September 15, 2008, 03:33:57 PM
Where are these combo pumps?
Here in the Chattanooga area, it seems like mainly it's the newly built or major remodeled conveneince stores. I've seen them at BP/Amoco, Midnight Oil and Exxon lately.
Chriss, observe the filter when you remove it, is it full? Is there some black sstuff in it? How much was the tow by the way?.
Somebody is confused. Or Just GOOFY !!
Industry standard is GREEN for diesel.
NO Mixing in hoses or lines of gasoline products and diesel for any reason.
I have never heard of a pump that switched from gas to diesel using the same hose and nozzle. Just doesn't happen. The EPA would be there in a flash and you know what happens then.... I could just imagine some guy with a Rolls getting a load of diesel into the engine..... Brrrrrr.. Chilling thought...
Gasoline blends ( Grades ) can use the same hose and nozzle... Never mixed
with diesel unless the tanker driver screwed up.
What you CAN get is trash from the storage tanks especially after a delivery. The driver dumps a load and stirs up all the gunk at the bottom of the tank.
Above ground storage tanks can get a LOT of condensation and gunk in them due to temerature changes.
I look for an Inline filter in the diesel hose usually. Some have them some don't.
Just don't buy fuel from a questionable place if the pumps look funky...
Dave....
When I use the pump with diesel and gas both on them never a problem for me just grab the nasty nozzle and stand in fuel and start pumping and never have I saw 1 hose used for both.but they do mix in the pipelines
Regarding the use of green pump nozzle covers, I've seen them on gasoline too lately. And here is an article about them:
http://www.brandingblog.com/2006/09/what_does_green.html
As for the combo pumps, if I still had a digital camera, I'd take a pic next time I see one. But since I don't, I'll have to leave that to someone else. Maybe those pumps have some kind of drain back feature or something. I don't know. I just try to avoid those pumps.
Sounds to me like you ran it out of fuel, or very possibly your tank was low, and when you turned the corner into the station, all your fuel ran to the opposite side of the tank, and you sucked in air. BTDT!! You'll have to reprime the fuel system.
craig
I am not sure but it you can crack the fuel ine after the fuel pump and see fi you are getting any flow there to make sure your fuel pump is still pumping.
If no flow you can try to prime the system and see if you can get it to flow again.
My guess not worth much in most places.
Bob
the tow was $550.00 (ouch!) >:( I'll see if there is anything in the filters.
Quote from: luvrbus on September 15, 2008, 03:53:21 PM
When I use the pump with diesel and gas both on them never a problem for me just grab the nasty nozzle and stand in fuel and start pumping and never have I saw 1 hose used for both.but they do mix in the pipelines
Yup, They do mix in the same pipeline.. Just use a water plug to separate
the fuels. Think I saw that on how its made.. Dunno..
Most of the pumps that I have seen have 2 sets of nozzles, One for diesel and one for gas.
Now the green caps idea... Hmmm.. Could be a LIGHTER green for E85 ?
The dark green is mostly diesel..
There was talk of a new kind of pump that had the drain-back feature a while back, the hose empties when the pump shuts down so in that case it is possible that is where the retailers are going.
Like in "Kaliforni" they capture the vapors and re-condense them for reuse.
Nozzles have a big accordian sock to catch the fumes. ( another EPA/CARB )
nonsense.
It's interesting to look at fuel dispenser hoses and nozzle contraptions so just about anything goes technically these days...
OWWW!
That tow bill would pay for 4 or 5 years worth of emergency roadside assistance.
I consider the ERS as just another part of the insurance bill.
Available from your insurer, your RV club, your auto club...just make sure it is really for your big RV.
And when you call for a tow, you tell them to be sure to send the right tow truck "I've got a Greyhound style bus, I need the big wrecker."
Good luck with the fuel delivery problem.
happy coaching!
buswarrior
chriss,
Do yourself a favor and get Good Sam road service, that $550 would have paid the GS dues for about six years and your tow could have been worse!!
Something that we found is that AAA has RV coverage, which includes up to 100 miles free towing!!! They didn't necessarily want to cover our bus but since it is titled as an RV they did.
Just a thought.
God bless,
John
The industry standard here in the good ole USA might be green for diesel, over in the Czech Republic, green is for gasoline.
I have never seen any combo nozzles either, either one for gas and one for diesel.
I'd do as others have suggested, check the filters and see how much fuel is in them. I would install some new ones anyway.
Just leave the Detroit running next time you fill up, no harm done. Gas is differant, more combustible.
Let us know what happened.
Paul
One time a few years ago, I pull into the big truck stop just East of Missoula, Mtana on I90 with my bus. I was tired after a long day on the road. I grab the yellow nozzle (yellow is for diesel in Canada) and let it pump by itself while I do my winshields, etc. Bus was iddling untill I noticed it started running rough and looked at the pump and realized I was putting gas in my tank!!!... I had my two young sons with me and they heard some strong language. I topped it off with diesel and then went in and bought a gallon of diesel treatment/lubricant and poured the whole thing in the tank, on top of probably 50/50 gas/diesel mix. That old DD never minded and has been fine ever since.
The moral of the story is: make damn sure you know what you are pumping!
JC
Quote from: gus on September 15, 2008, 03:33:57 PM
The only time I almost goofed was one station that had a green nozzle that dispensed gas, only time I ever saw green for gas. I now remember the brand, BP, but I did pump a gallon or two of gas before I caught it. Even that one was not a combo setup, the diesel nozzle was black??
That's the British arrangement if it helps (and BP = British Petroleum of course). Black for diesel, green for unleaded, blue for high-octane unleaded, yellow for LPG.
Jeremy
Ouch is right!!! I have a emergency road service ryder on my insurance policy, costs about $5 a year. I have never used it so do not know how good it is.
Most BP stations here have green on gas and Black on diesel.
Chris,
The first thing I would do is to rig an electric primer pump at the fuel tank (lot's of info in the archives here).
The next is to know how to replace and prime your filters at the side of the road and how to do basic trouble shooting of the fuel system.
I mean no offense, but most bus nuts would not opt for a tow just because the engine won't start, usually a simple fix.
Len
Quote from: gumpy on September 15, 2008, 04:08:07 PM
Sounds to me like you ran it out of fuel, or very possibly your tank was low, and when you turned the corner into the station, all your fuel ran to the opposite side of the tank, and you sucked in air. BTDT!! You'll have to reprime the fuel system.
craig
I might have, but I don't think I was too low, I only went about 400 miles with a full tank. since fuel was still at a low price I thought, why not fill back up.
I hope I don't have to reprime the system!
Quote from: Len Silva on September 16, 2008, 06:57:43 AM
Chris,
The first thing I would do is to rig an electric primer pump at the fuel tank (lot's of info in the archives here).
The next is to know how to replace and prime your filters at the side of the road and how to do basic trouble shooting of the fuel system.
I mean no offense, but most bus nuts would not opt for a tow just because the engine won't start, usually a simple fix.
Len
Len,
No offense taken, I was in a hurry and it was raining like crazy! I spun the fuel filters off and they were full of fuel so I though it might be something more serious. I emptied the fuel filters, re filled them and put em back on, then tried to start it again, with no luck. and my batteries started to get low so I gave up and decided to have it towed. thanks for the advice on the primer pump, I'll check the archives on that.
Chris
Quote from: buswarrior on September 15, 2008, 05:22:05 PM
OWWW!
That tow bill would pay for 4 or 5 years worth of emergency roadside assistance.
I consider the ERS as just another part of the insurance bill.
Available from your insurer, your RV club, your auto club...just make sure it is really for your big RV.
And when you call for a tow, you tell them to be sure to send the right tow truck "I've got a Greyhound style bus, I need the big wrecker."
Good luck with the fuel delivery problem.
happy coaching!
buswarrior
I am definately looking into ERS insurance!
thanks,
Chris
Quote from: buswarrior on September 15, 2008, 05:22:05 PM
OWWW!
That tow bill would pay for 4 or 5 years worth of emergency roadside assistance.
I consider the ERS as just another part of the insurance bill.
Available from your insurer, your RV club, your auto club...just make sure it is really for your big RV.
And when you call for a tow, you tell them to be sure to send the right tow truck "I've got a Greyhound style bus, I need the big wrecker."
Good luck with the fuel delivery problem.
happy coaching!
buswarrior
I lived and learned!
Oh, one other thing that I don't think was mentioned... did you check to make sure you didn't trip the emergency shutdown flapper on the air intake? I forget about that, as it's not on the 92 series engines.
chris
use your air compressor to prime the engine.
Put the air hose in the tank, wrap with a cloth, put a small amount of air to the tank.
not enough to blow it up.
might need to crack the line at the primary filter and let the air out.
uncle ned
When you crank the engine are you getting white smoke? If not, you are not getting fuel into the cylinders. If you are getting white smoke and it is not starting, check the emergency shutdown flap on top of the blower in the air intake tubing. Jack
Quote from: uncle ned on September 16, 2008, 07:46:30 AM
chris
use your air compressor to prime the engine.
Put the air hose in the tank, wrap with a cloth, put a small amount of air to the tank.
not enough to blow it up.
might need to crack the line at the primary filter and let the air out.
uncle ned
What about the overflow/vent pipe?
on a gm the vent pipe is inside of the fuel filler. it whistles when it starts to get full
ned
Those GM guys thought of everything!!
Well, what was wrong with the bus? Inquiring minds want to know.
Quote from: bigjohnkub on September 17, 2008, 08:31:01 AM
Well, what was wrong with the bus? Inquiring minds want to know.
I still haven't got it going yet. when I tried to start it today, It ran for about 30 sec. then slowly shut back down. then couldn't start it again. I checked the fuel filters and they were full of Diesel. I don't believe it was gas, because it smelled like diesel. I couldn't trace any gas smell. when I tried starting it back up, it puffed white smoke, so it seems to be getting fuel. I'm wondering if it could be an electrical problem? any suggestions?
thanks,
Chris
Without going back and re-reading stuff--I assume you have disqualified the emergency shut down or anything else obstructing the air intake. Could it be an intermittent bad contact in your ignition/main switch or fuel solenoid? Could it be the fuel pump? Not being a expert, but as I understand it there are only three elements to starting--fuel, air, and compression. Will it start with starting fluid?
Quote from: chriss on September 18, 2008, 08:29:42 PM
Quote from: bigjohnkub on September 17, 2008, 08:31:01 AM
Well, what was wrong with the bus? Inquiring minds want to know.
I still haven't got it going yet. when I tried to start it today, It ran for about 30 sec. then slowly shut back down. then couldn't start it again. I checked the fuel filters and they were full of Diesel. I don't believe it was gas, because it smelled like diesel. I couldn't trace any gas smell. when I tried starting it back up, it puffed white smoke, so it seems to be getting fuel. I'm wondering if it could be an electrical problem? any suggestions?
thanks,
Chris
This sounds a lot like an emergency shutdown like is found on the MCIs. I didn't think GMs had that, but maybe they do.
First, do you have a switch somewhere (maybe in the engine compartment) for killing the engine that may be in the wrong position.
Second, when you started if, was the air fully built up. Try again, and this time, watch the shutdown cylinder on the engine. If it slowly pushes the fuel cutoff lever as the air builds up and shuts the engine down, then you have a problem with the shutdown system being activated. On the MCIs, the temp stats and oil pressure are hooked into this. There might also be water level sensors hooked into this. Usually, they activate by grounding, and the sensors can go bad. If you remove the wire from the terminal, it will disable the sensor, and should allow the engine to start, if that's what's causing the problem.
If it's not that, then it could very well have air in the fuel pump; possibly as a result of the turn into the fuel station, as I mentioned before. Your fuel pickup tube could be cracked or broken in the tank allowing it to suck air, or possibly the fuel level just got too low and you sucked air in when you turned. I've done many times.
If it starts, it's getting fuel. If it dies a slow death, it's running out of fuel for some reason. Probably one of the reasons stated above. Make sure you check the emergency shutdown flapper, too, in case it accidentally got triggered. I wouldn't expect it to start, though, if it is closed, as it wouldn't be able to get air to support combustion, but maybe there's enough there to let it run for a bit.
craig
On a GM (my 4104) that's exactly what will happen if you try to start it from the rear without having the front run switch on. It will run for a short while until enough air builds up to shut it off.
Quote from: Len Silva on September 19, 2008, 07:31:20 AM
On a GM (my 4104) that's exactly what will happen if you try to start it from the rear without having the front run switch on. It will run for a short while until enough air builds up to shut it off.
I did start it from the rear, but I had the front run switch on. The air pressure is down on the bus. I doesn't run long enough to build pressure.
Quote from: gumpy on September 19, 2008, 04:33:34 AM
Quote from: chriss on September 18, 2008, 08:29:42 PM
Quote from: bigjohnkub on September 17, 2008, 08:31:01 AM
Well, what was wrong with the bus? Inquiring minds want to know.
I still haven't got it going yet. when I tried to start it today, It ran for about 30 sec. then slowly shut back down. then couldn't start it again. I checked the fuel filters and they were full of Diesel. I don't believe it was gas, because it smelled like diesel. I couldn't trace any gas smell. when I tried starting it back up, it puffed white smoke, so it seems to be getting fuel. I'm wondering if it could be an electrical problem? any suggestions?
thanks,
Chris
This sounds a lot like an emergency shutdown like is found on the MCIs. I didn't think GMs had that, but maybe they do.
First, do you have a switch somewhere (maybe in the engine compartment) for killing the engine that may be in the wrong position.
Second, when you started if, was the air fully built up. Try again, and this time, watch the shutdown cylinder on the engine. If it slowly pushes the fuel cutoff lever as the air builds up and shuts the engine down, then you have a problem with the shutdown system being activated. On the MCIs, the temp stats and oil pressure are hooked into this. There might also be water level sensors hooked into this. Usually, they activate by grounding, and the sensors can go bad. If you remove the wire from the terminal, it will disable the sensor, and should allow the engine to start, if that's what's causing the problem.
If it's not that, then it could very well have air in the fuel pump; possibly as a result of the turn into the fuel station, as I mentioned before. Your fuel pickup tube could be cracked or broken in the tank allowing it to suck air, or possibly the fuel level just got too low and you sucked air in when you turned. I've done many times.
If it starts, it's getting fuel. If it dies a slow death, it's running out of fuel for some reason. Probably one of the reasons stated above. Make sure you check the emergency shutdown flapper, too, in case it accidentally got triggered. I wouldn't expect it to start, though, if it is closed, as it wouldn't be able to get air to support combustion, but maybe there's enough there to let it run for a bit.
craig
I do have an emergency shutdown switch, but it shows that it is not engaged. I don't have any air pressure at all. It doesn't run long enough to build up. where would the flapper be located?
thanks
Chris
There is a 90degree housing right on top of the blower it should be there. It is held open by a catch if you spring the catch it shuts with the help of spring.
Quote from: quantum500 on September 19, 2008, 08:43:49 AM
There is a 90degree housing right on top of the blower it should be there. It is held open by a catch if you spring the catch it shuts with the help of spring.
I'll check it out!
thanks for your help!
Chris
Chriss;if you have a paper air cleaner check and make sure it's hasn't come apart,also there is a screen on top of the blower air inlet that will plug check all of your intake hoses make certain they are not collapsing you have a air problem somewhere if yiu are blowing some as it trying to start. does it blow black smoke when it starts have a great day
Quote from: makemineatwostroke on September 19, 2008, 09:08:45 AM
Chriss;if you have a paper air cleaner check and make sure it's hasn't come apart,also there is a screen on top of the blower air inlet that will plug check all of your intake hoses make certain they are not collapsing you have a air problem somewhere if yiu are blowing some as it trying to start. does it blow black smoke when it starts have a great day
no, it puffs out white smoke.
Chris
Quote from: gumpy on September 19, 2008, 04:33:34 AM
Quote from: chriss on September 18, 2008, 08:29:42 PM
Quote from: bigjohnkub on September 17, 2008, 08:31:01 AM
Well, what was wrong with the bus? Inquiring minds want to know.
I still haven't got it going yet. when I tried to start it today, It ran for about 30 sec. then slowly shut back down. then couldn't start it again. I checked the fuel filters and they were full of Diesel. I don't believe it was gas, because it smelled like diesel. I couldn't trace any gas smell. when I tried starting it back up, it puffed white smoke, so it seems to be getting fuel. I'm wondering if it could be an electrical problem? any suggestions?
thanks,
Chris
This sounds a lot like an emergency shutdown like is found on the MCIs. I didn't think GMs had that, but maybe they do.
First, do you have a switch somewhere (maybe in the engine compartment) for killing the engine that may be in the wrong position.
Second, when you started if, was the air fully built up. Try again, and this time, watch the shutdown cylinder on the engine. If it slowly pushes the fuel cutoff lever as the air builds up and shuts the engine down, then you have a problem with the shutdown system being activated. On the MCIs, the temp stats and oil pressure are hooked into this. There might also be water level sensors hooked into this. Usually, they activate by grounding, and the sensors can go bad. If you remove the wire from the terminal, it will disable the sensor, and should allow the engine to start, if that's what's causing the problem.
If it's not that, then it could very well have air in the fuel pump; possibly as a result of the turn into the fuel station, as I mentioned before. Your fuel pickup tube could be cracked or broken in the tank allowing it to suck air, or possibly the fuel level just got too low and you sucked air in when you turned. I've done many times.
If it starts, it's getting fuel. If it dies a slow death, it's running out of fuel for some reason. Probably one of the reasons stated above. Make sure you check the emergency shutdown flapper, too, in case it accidentally got triggered. I wouldn't expect it to start, though, if it is closed, as it wouldn't be able to get air to support combustion, but maybe there's enough there to let it run for a bit.
craig
I just tried starting, and it ran until pressure built up and the shutdown cylinder pushed the cutoff lever, just like you mentioned, so it must the shutdown system. any other troubleshooting I can try in order to pinpoint?
thanks,
Chris
disconnect your shut down cylinder and see if it will keep ruining the smoke part is what I don't understand, that is caused by fuel,air or low compression have a great day
Quote from: makemineatwostroke on September 19, 2008, 10:47:24 AM
disconnect your shut down cylinder and see if it will keep ruining the smoke part is what I don't understand, that is caused by fuel,air or low compression have a great day
I held the lever back manually, and it kept running just fine, so something is causing the shutoff to engage. ???
Chriss, follow your air line from the shutdown to the skinner valve (will have 2 air lines and 1 wire about 2 in round) and check for a broken wire or the valve itself could be bad ( power on closed, power off open to kill the engine) have a great day
Again, is there a manual switch in the engine compartment for shutting down the engine, and if so, is it in the run positon. I'm not familiar with GMs, but the MCI has a switch that is basically run or off. If it's in the off position, it will act just like your's is doing. I'm not talking about the emergency shutdown switch, as that switch trips the air intake baffle. This would be a different switch that would shut down the engine normally from the rear control panel.
Next, disconnect the temp stats and oil pressure switch one at a time, trying to start between each. If it has an electronic shutdown system, these will be connected into it, and a sensor may be bad. If you starts and runs after you unhook a sensor wire, that's the bad one. Also check for a coolant level sensor and do the same with it.
craig
I cannot help much with a GM, but be very careful running the bus with the shutdown lever held open. You may have a real problem like no oil pressure or no coolant. HTH jim
Quote from: jjrbus on September 19, 2008, 05:49:59 PM
I cannot help much with a GM, but be very careful running the bus with the shutdown lever held open. You may have a real problem like no oil pressure or no coolant. HTH jim
Initially I was confused by Jim's statement, and reread it. He's absolutely correct. I've been telling you to unhook you sensors, but the first thing you need to do is make sure they are not activating for good cause. Make sure you have proper oil pressure and proper coolant level before continuing with my previous suggestions.
Thanks Jim
craig
Sounds like a safety shut down. You said it ran a little the next morn. Try removing the air line from shut down valve an see if it contineues to run If air builds up and it shuts down could be a grounded shut down alarmstat or low oil, high temp ect.
If you remove the air shut down and a 2 stroke does not start it is a fuel problem You can drive it around the world with it disconnected. I owned 10 buses 5, GMs If it doesn't start after 10 sec it's getting air or not getting fuel or lost prime .
Quote from: Beatenbo on September 19, 2008, 08:39:59 PM
If you remove the air shut down and a 2 stroke does not start it is a fuel problem You can drive it around the world with it disconnected. I owned 10 buses 5, GMs If it doesn't start after 10 sec it's getting air or not getting fuel or lost prime .
thanks, I'll check out jjrbus' suggestion first to be sure that there is nothing seriously wrong, and if everything there is fine, then I'll disconnect it and try troubleshooting it from there.
Chris
Chriss,
Some GMs have a shutdown switch on the rear panel. There are usually four switches, the second one from the right facing the engine is the "Run" switch. If this is accidentally hit (Easy to do) it will run until air pressure builds up and stop. I know all about how this works!! It does the same thing as leaving the front switch "Off".
Quote from: gus on September 20, 2008, 07:50:05 PM
Chriss,
Some GMs have a shutdown switch on the rear panel. There are usually four switches, the second one from the right facing the engine is the "Run" switch. If this is accidentally hit (Easy to do) it will run until air pressure builds up and stop. I know all about how this works!! It does the same thing as leaving the front switch "Off".
thanks for the suggestion, I did check it today and the switch was not on.
I think it might be a sensor, because I disconected the valve that shuts the engine down, and the bus ran just fine. I also made sure the coolant and
oil levels were ok. which they were.
now i need to check down the line to see which sensor or valve is bad.
thanks
chris
[/quote]
I also made sure the coolant and
oil levels were ok. which they were.
now i need to check down the line to see which sensor or valve is bad.
thanks
chris
[/quote]
When you say you checked the oil level, you mean oil pressure? You can have plenty of oil, but if the pump is bad you will have no pressure. But you knew that right! Jim
Quote from: jjrbus on September 21, 2008, 07:04:49 PM
When you say you checked the oil level, you mean oil pressure? You can have plenty of oil, but if the pump is bad you will have no pressure. But you knew that right! Jim
Again, Jim is absolutely correct. The sensor is on pressure, not level.
Quote from: gumpy on September 21, 2008, 07:24:54 PM
Quote from: jjrbus on September 21, 2008, 07:04:49 PM
When you say you checked the oil level, you mean oil pressure? You can have plenty of oil, but if the pump is bad you will have no pressure. But you knew that right! Jim
Again, Jim is absolutely correct. The sensor is on pressure, not level.
I only checked the levels, but the oil pressure gage on the dash reads like it normally does while running, but the guage could be wrong. the other guage on the back above the engine has been broken for years. is there another way to check pressure besides the gauge?
chris
Go out and buy a mechanical gauge! You will not correct the problem until you know for sure what your pressure is. They aren't that much. Heck even go to NAPA, Auto Zone or any parts place.
Paul
If he didn't have oil pressure as much as he has started the engine it would be a basket case by now
Quote from: luvrbus on September 21, 2008, 08:17:52 PM
If he didn't have oil pressure as much as he has started the engine it would be a basket case by now
Well as usual Clifford you are correct! But at the same time I was once told it only took 2.5 lbs to make a DDEC unit happy! So it is possible to have VERY LOW pressure that may not be enough for the conventional low pressure switch! FWIW ;D BK ;D
Quote from: Dreamscape on September 21, 2008, 08:09:55 PM
Go out and buy a mechanical gauge! You will not correct the problem until you know for sure what your pressure is. They aren't that much. Heck even go to NAPA, Auto Zone or iany parts place.
Paul
paul,
good point, i'll get a guage and double check to be sure.
thanks,chris
Chris,
I just like the mechanical gauge to check, I always go by that when I fire mine up and then compare the reading to the electrical one on the dash.
Good Luck,
Paul
Quote from: luvrbus on September 21, 2008, 08:17:52 PM
If he didn't have oil pressure as much as he has started the engine it would be a basket case by now
No need to scare the guy.
He said his dash gauge is reading normal as it always has. More than likely, that means that he has not lost oil pressure.
Yes, he replace the mechanical gauge in the engine compartment. But it still sounds like a sensor in the safety shutdown system is causing the problem. I'd start with the temp sensors. They're easy to get to.
craig
wasn't my intention to scare the guy gumpy the low oil pressure sensor on the shutdown on a Detroit 2 stroke very seldom goes bad or work when they idle hot some will read O on the the gauge that is why the rpm on idle is so important on these engines I've seen them idling at 300 or 400 rpm with no oil pressure showing and not shutdown fwiw
My 4104 has a mechanical oil press gage installed back on the engine. I'm positive this was the way it was built because there are references to it in the MM and I assumed that all buses have them??
Presumably it was installed there for the use of mechanics working on the engine since there are starter and run switches there also.
Quote from: gus on September 22, 2008, 02:53:20 PM
My 4104 has a mechanical oil press gage installed back on the engine. I'm positive this was the way it was built because there are references to it in the MM and I assumed that all buses have them??
Presumably it was installed there for the use of mechanics working on the engine since there are starter and run switches there also.
Yes, I have one in the back above the engine, but it is broke. I'll end up pulling that out and replacing it.
Chris
Quote from: gumpy on September 22, 2008, 04:29:10 AM
Quote from: luvrbus on September 21, 2008, 08:17:52 PM
If he didn't have oil pressure as much as he has started the engine it would be a basket case by now
No need to scare the guy.
He said his dash gauge is reading normal as it always has. More than likely, that means that he has not lost oil pressure.
Yes, he replace the mechanical gauge in the engine compartment. But it still sounds like a sensor in the safety shutdown system is causing the problem. I'd start with the temp sensors. They're easy to get to.
craig
is it common for the shutdown valve itself to go bad? is there a way of checking it, because maybe the valve itself is bad. just a thought.
Chris
Quote from: chriss on September 22, 2008, 03:06:24 PM
is there a way of checking it, because maybe the valve itself is bad. just a thought.
Chris
Start the engine with the wire to the low oil pressure sender disconnected. With the engine running, with oil pressure (and air pressure for engine stop), connect the wire to the sender. If engine stops when wire is connected, sensor is bad. Jack
Quote from: JackConrad on September 22, 2008, 03:41:32 PM
Quote from: chriss on September 22, 2008, 03:06:24 PM
is there a way of checking it, because maybe the valve itself is bad. just a thought.
Chris
Start the engine with the wire to the low oil pressure sender disconnected. With the engine running, with oil pressure (and air pressure for engine stop), connect the wire to the sender. If engine stops when wire is connected, sensor is bad. Jack
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thanks Jack!