| Author | Message | ||
| John and Barb Tesser (Bigrigger)
Registered Member Username: Bigrigger Post Number: 163 Registered: 9-2007 Posted From: 24.179.147.233  Rating: N/A |
OK, I started my MCI 5C DD 6V71 today. The dash mounted starter switch has never worked, so I throw the master switch on the dash to "on" and then walk back and start it at the rear panel. All good until I went to shut it off. This time, the master dash switch had no effect, tried the covered "energency shut off switch" to no effect. Went back to the back and hit the off switch on the back panel, still nothing. Tried that switch several times and then I could hear the motor slow down. After several more tries with the rear panel shutoff switch, it finally shut down. I can hear that switch running a solenoid and now will allow the motor to run or shut it off as needed, however the master switch on the dash still has no effect. I am wondering if the master switch shuts off a different fuel solenoid than the one on the rear? Maybe someone can save me some tracing. Thanks in advance. | ||
| Moe Hollow (Moehollow)
Registered Member Username: Moehollow Post Number: 88 Registered: 12-2007 Posted From: 71.102.27.164 Rating: N/A |
The master switch does shut off the fuel. However,it does so by activating an air plunger that pushes the fuel valve closed. You are aware that you must have some air build up for this to work? It would be good to watch as this happens so you can see the system at work. That way, if you want to shut it down before the air is up, you can do it manually, probably with a stick instead of putting your hand near that belt. | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 443 Registered: 3-2007 Posted From: 71.55.197.237  Rating: N/A |
Bigrigger, Check first to see if your switch in the rear marked normal/off/rear, start switch. it will need to be in the normal position for front start and rear for the rear starting. In the off position nothing will work. Chanches are you have a problem there with the whole thing. The swith is nothing to find as it is a common item, I think it is a double pole,double throw [DPDT]. Since the rear of the coach is always prone for moisture,oil I would start there before going anywhere. I also found at Harbor Freight the other day a wire traceing unit, 30.00 that is great for tracing wiring as it has a sending unit and reciever and works great. Good Luck gomer | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 660 Registered: 7-2006 Posted From: 75.211.248.36 Rating: N/A |
Gomer...U R a whiz..I would agree with you. (on the first part)...  Don't know about the HF item,but, if you say so....it must be!. RCB | ||
| John and Barb Tesser (Bigrigger)
Registered Member Username: Bigrigger Post Number: 164 Registered: 9-2007 Posted From: 24.179.147.233 Rating: N/A |
Thanks all, Moe I had about 60 psi up when I tried to shut it off, but it wasn't fully aired. Gomer, thanks for the tracer tip, I really need to get one as the PO has wires hanging everywhere in the back and no real way to know whats standard. | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 444 Registered: 3-2007 Posted From: 71.55.197.237 Rating: N/A |
RC. Thanks for the comment and I thank you for what you do for me in your posts. It is people like you and others that make the BN board what it is, and I still want my shirt.LOL Bigrigger;; Your are welcome. Gomer | ||
| Keith Wood (Ft6)
Registered Member Username: Ft6 Post Number: 109 Registered: 8-2008 Posted From: 75.208.237.83 Rating: N/A |
I will tell you exactly what happened. When you tried to shut down, you didn't have enough air up. The electric shutdown solenoid operated, opening to fill the air solenoid, but you didn't have enough air. As your pressure built up, the air piston pushed gently against the fuel cutoff pawl. When you hit the emergency cutoff, the same thing happened for the emergency sear. By leaving the shutdown solenoid open, pressure gradually increased, decreasing the fuel flow. The air solenoid is intended to work as a hammer, and the pawl as a nail. That is, when you have air up, the ram punches out and drives the pawl, overcoming the spring loading. When you build pressure with the piston already resting on the pawl, you need MORE air to make the pawl move. Imagine trying to drive a nail by pushing down on it with the hammerhead. If you have a low-air issue and need to shut down the engine, the best way is to pop the engine cover and manually release the emergency shutdown sear with a screwdriver. Those of us with turbos don't have this option, but if the engine is still cold, it doesn't hurt the turbo to shutdown by operating the pawl manually. | ||
| John and Barb Tesser (Bigrigger)
Registered Member Username: Bigrigger Post Number: 166 Registered: 9-2007 Posted From: 24.179.147.233 Rating: N/A |
Wow, thanks for all the info Keith. I have had Detroits in trucks several times since the early 70's but have never encountered this problem. Of course they were all used regularly in over-the-road operation. I think my troubles are comeing from a vehicle sitting in the snow bank for 6 months and then expecting it to be like it was last fall! | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 666 Registered: 7-2006 Posted From: 75.208.96.90 Rating: N/A |
So, then....Bigrigger... we are to ass u me that it did it work out as Keith stated? Thanx... and to you Gomer; ....shirt??? Me memory 'scapes me....bring me up to date>>> ...must have something to do with maturity??? Seems I recall something, but if I started to look for it....well, I am sure U understand! Happy May Day! (Anyone in the service of our country in 1955? Remember what happened on that day?) RCB | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 448 Registered: 3-2007 Posted From: 71.55.197.237 Rating: N/A |
RC PLEASE POST ANOTHER MESSAGE ASAP. Did you see how many posts you have? 666 GET IT OFF QUICK GOMER | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 883 Registered: 11-2005 Posted From: 208.54.200.90  Rating: N/A |
RC, Perfect number of posts, my lucky number! | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 668 Registered: 7-2006 Posted From: 70.212.246.64 Rating: N/A |
................... Proverbs 3:5&6..... youse guys are ALERT! Thanx RCB |