| Author | Message | ||
| captain ron (Captain_ron)
Registered Member Username: Captain_ron Post Number: 628 Registered: 1-2005 Posted From: 66.174.93.102 Rating: N/A |
When I first start my bus and kick on the fast idle it will run a few seconds or a minute or two then kick the fast idle off then will quit alltogether. I can restart it after a few minutes then it's usualy ok. any ideas? Hope to not have to mess with it till I get to Bryces bus ralley in a couple weeks. and hope to see quite a few of you there. | ||
| Bob greenwood (Bob_greenwood)
Registered Member Username: Bob_greenwood Post Number: 254 Registered: 7-2006 Posted From: 4.227.117.98 Rating: N/A |
fuel filters.. have no idea if your bus is computer controled,but if a diesel engine stops running,it's out of fuel... we already know,it's not points,not plugs,not plug wires | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 53 Registered: 12-2000 Posted From: 71.29.27.163 Rating: N/A |
Sounds like it might be something in the shut down circuit. Len | ||
| Bob greenwood (Bob_greenwood)
Registered Member Username: Bob_greenwood Post Number: 255 Registered: 7-2006 Posted From: 4.227.117.98 Rating: N/A |
or, it might be looseing it's prime, you run the filters out,then it dies,on restart,the line is now full, | ||
| Spencer Champion (Spencer)
Registered Member Username: Spencer Post Number: 7 Registered: 4-2006 Posted From: 72.152.136.132 Rating: N/A |
On my 8v71 there was a crack in the cap nut on the hose. Someone had, get this, taped the nut where the crack was. I dove that 4501 from California to Georgia without a problem. Tape got tired and it would run a while and quit. Changed filters, filled filters and still run awhile and quit. I got lucky and pulled the tape off to see why it was there. Saw the crack and replaced the hose. Long winded way to say what Bob above did. Looseing prime would be my first guess. Good luck. Spencer | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 26 Registered: 8-2006 Posted From: 24.127.158.82 Rating: |
Ron, If the bus pictured is the one with the problem, and the original engine, the shutdown is accomplished with air through an electric valve. All of these buses will start with a failed run circuit, and run until enough air builds up to push the shutdown plunger. Put it in neutral, turn on the master, go around the back and start it from the rear. Watch the shutdown plunger, and see if it comes out slowly, and if so, at full travel, the engine will die. This also explains the later restart, as the air will have leaked off, and it will run until it builds up some air again... | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 209 Registered: 11-2005 Posted From: 63.97.117.37 Rating: N/A |
George is correct and to add to his post there is probably an accidentally thrown switch somewhere. On a 4104 there is a switch for mechanics to use to cut off the engine from the rear. If this is accidentally bumped it will do just as George says. Don't ask me how I know this! (Message edited by gusc on October 19, 2006) | ||
| captain ron (Captain_ron)
Registered Member Username: Captain_ron Post Number: 629 Registered: 1-2005 Posted From: 66.174.79.228 Rating: N/A |
I had problems with my skinner valve on the old bus. and this problem seems the same. the bus runs 99% of the time this is an intermitent problem. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 27 Registered: 8-2006 Posted From: 24.127.158.82 Rating: N/A |
Capn, The majority of us are at it again, a problem in the shutdown circuit. The one thing I forgot the first time, is that the "skinner valve" must be ENERGIZED for the bus to run. So, a loose wire, or a loose ground, will de-energize the valve and put air pressure to the shutdown plunger, eng dies. This circuit goes thru the hot engine and low oil press. relay also, which means there can be a LOT of loose places. A suggestion is to take a 3/8 nut driver and tighten every nut on every stud in all four junction boxes, whew. We did this in Chuck's bus, for the same reason, and found over 20 loose terminals! The coil in the valve could be intermittent also.. HTH | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 211 Registered: 11-2005 Posted From: 63.97.117.20 Rating: N/A |
If there is less than about 60 psi in the air system when you start the bus I disagree with George since the air shutdown won't work until the pressure builds up. On a GMC the shutoff valve is open when there is no air regardless of the electrical circuit status. Air shuts off the engine, not electricity. Electricity keeps the air valve closed. When the electricity is turned off the air valve opens and air pressure to the shutoff cylinder shuts off the fuel. As long as there is enough air pressure the engine will not start with the electricity off. If the bus air pressure is above 60psi when you start it I agree with George. | ||
| Glenn Williams (Glenn)
Registered Member Username: Glenn Post Number: 5 Registered: 6-2006 Posted From: 207.179.92.243 Rating: N/A |
Good to see you on the post Ron! I agree with George about the loose circuits for the electric solonid. That's what the problem was in your old bus. I was glad it was an easy fix. Glenn |
