| Author | Message | ||
| hiwaycallin (Hiwaycallin)
Registered Member Username: Hiwaycallin Post Number: 7 Registered: 10-2007 Posted From: 208.98.218.205 Rating: N/A |
I apologize in advance for such a beginner question. I am wondering how long, on average, does it take to properly start a bus? I have heard that it can take from between 10-20 minutes of idling time in order to build up enough air pressure for the brakes and suspension to operate properly. Is this correct? Does the start up time vary much between makes, models, and "era's" of the various coaches out there? Thanks in advance, and again, sorry if this is a stupid question. | ||
| L James Jones Jr (Jamo)
Registered Member Username: Jamo Post Number: 33 Registered: 11-2007 Posted From: 24.59.119.14  Rating: N/A |
HWC, Being a newbie myself, I would say this was far from a stupid question. My 4104-204 takes a good 10 minutes from firing to full bags & brakes. Maybe 15. PO (Dounan) did tell me of a leaker on my front axle, but I don't hear anything major there. Bleeds down over 1.5 days though. The rest of the stuff seems OK, but as I said, I'm a newbie to this too. Once spring hits, I'm all over this board with plenty of "stupid" questions. As far as I'm concerned, ask away. I love to learn from others... | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1200 Registered: 12-2000 Posted From: 76.66.19.122  Rating: N/A |
Great question HWC! It depends on how empty the air system is when you start, whether it has leaks, and the health and capacity of the air compressor mounted to the engine. Depending on bus model, and condition of all the valving, the air gauge on the dashboard does not indicate what is in the whole system, so you may or may not be starting from what is indicated. Many busnuts install an electric compressor to pre-fill the tanks so that they may start the engine and drive away. This is important in campground settings, where few if any will appreciate the big diesel powered mosquito fogger in the morning. Ask more! happy coaching! buswarrior | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 195 Registered: 3-2007 Posted From: 76.4.151.87 Rating: N/A |
bus worrier LOL there ya go again, trying to confuse the newbie's on the board.. but again you are right[shucks] and I admit it that a small air compressor in campgrounds sure save a lot of hurt feelings LOL Gomer | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 589 Registered: 11-2005 Posted From: 208.54.200.183  Rating: N/A |
highway, Just one small point, if your bus has a DD two stroke engine you should always use fast idle to build up air pressure. The 4104 GMC manual says to use 1/3 throttle for warm up. DDs do not like to idle, it chokes them up. | ||
| Tony LEE (T_lee)
Registered Member Username: T_lee Post Number: 19 Registered: 11-2007 Posted From: 124.180.46.247 Rating: N/A |
"if your bus has a DD two stroke engine you should always use fast idle to build up air pressure." Trouble is you need air pressure to get fast idle and the first 60psi is the slowest. I have a 'calibrated' stick to hold the pedal down to give an idle speed similar to fast idle. (Message edited by t_lee on February 21, 2008) | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 223 Registered: 10-2006 Posted From: 66.90.229.183 Rating: N/A |
IF the air system is OK it should only be 5 min on a GM, for some reason the MCI take way longer. Yes the fast idle requires air , but it comes up in about 1-2 min , and the coach fills faster from there. It is a bit of ca$h to replace all the leveling valves , but for most folks , once done the coach will stand for weeks. Be wary of using the Shop Fill valve unless your compressor makes water free air (like for painting). FF | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 730 Registered: 12-2000 Posted From: 70.0.34.173  Rating: N/A |
When we added a shop air fitting, we installed it on top of the "ping" tank. From them ping tank the shop air goes through the OEM dryer. Jack | ||
| Amy E. Riley (Familycoach)
Registered Member Username: Familycoach Post Number: 16 Registered: 9-2007 Posted From: 130.76.96.19 Rating: N/A |
HWC, It takes our bus (GM4905) about 5 minutes to air up and be ready to go. That is even if the bus has been sitting for a while. Amy | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 130 Registered: 10-2003 Posted From: 66.165.176.60  Rating: N/A |
Our FLX only takes 3-4 minutes from 0 psi but as has been said the amount of air systems we have is limited....brakes, wipers and drivers seat | ||
| hiwaycallin (Hiwaycallin)
Registered Member Username: Hiwaycallin Post Number: 8 Registered: 10-2007 Posted From: 208.98.218.205 Rating: N/A |
Wow, thank you all for your replies. All that information helps a lot! So, just to be clear, if my bus has been sitting for a couple days, it might take some time to build up the air pressure, but that could be done without having to idle (i.e. with an aux. compressor)? But let's say I'm on the road and stop somewhere for lunch for an hour or so, I could pretty much start her up and drive off (assuming I don't have any leaks)? Thanks again. HWC | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1202 Registered: 12-2000 Posted From: 76.68.123.128 Rating: N/A |
Hello HWC I might suggest that if your bus won't hold enough air to simply start and go after being stopped for an hour, there is some important maintenance that needs to be done to the air system. Whether our converted coaches must meet the letter of the law with regard to DOT inspection criteria, or not, every busnut needs to answer for themselves: How far short of the DOT inspection standards do I really want to be? Knowingly or not, we all make those decisions every time we head out on the road. Purposeful and informed or ignorantly blissful? happy coaching! buswarrior | ||
| hiwaycallin (Hiwaycallin)
Registered Member Username: Hiwaycallin Post Number: 9 Registered: 10-2007 Posted From: 208.98.218.205 Rating: N/A |
Thanks BW, for the information ... and the wisdom. |