Troubleshooting Starting Issues on a 1999 Prevost H3-41 with Detroit Diesel

[snocown]

Hello everyone, good day or night to whoever comes across this.

I had a quick question about the engine of the Prevost bus.

We have a detroit deisel engine on a 1999 h3-41 Prevost.

We had driven it away from the seller and made it to a quarter mile away from the place we dropped the bus off before the battery died mid drive I would assume. I am not 100% sure because I had started the bus 5 minutes after needing to pull over to the side of the road and then it worked again and I managed to get the bus where we needed to.

Today we had reversed the bus to get it in front of our mother in laws house. After turning the bus off for a few minutes and turning it on again to do the air decompression I had turned the bus off yet again. My father in law then wanted me to start the bus again because he wanted to play around and drive it but when we tried to start it it would make a click sound that reverberated through the whole bus and would not start.

I am wondering if this is a battery issue. My father in law says it sounds like the engine is trying to start but isnt getting enough power. I would assume that the battery would charge while driving but it could be bad batteries.

My wife is wondering if low gas could cause the bus to not start as well because we were going to get gas for the bus next time we drove it, we just wanted to do it at night since that day was my first time driving a bus ever. I am getting the hang of it thankfully, but id rather do it at night with less cars to worry about.

It could also be a bad engine i know.

As for the previous owners. They owned it for 4 years and started the bus once a week to get the fluids flowing and they drove it around their block they claim. They also used the bus for camping.

It all is what it is at the end of the day. We are just hoping to get some insights before we try to get a mechanic to come check out the bus. We were going to do that before this issue occured, but we just want this issue figured out before doing that now. If its just the battery its an easy fix after all.

I did not take a video yet sadly, my wife just wanted to get away and rest because this gave her a headache. I will attempt to post a photo of the dash with this post.

 

[s2mikon]

Do you have a voltmeter to read the battery voltage at the terminals? It sounds like you have batteries that are very low or dead.

 

[Crown_Guy]

Oh Boy... Where to start. Whatever possessed you to buy a super high quality and complex (Expensive in every way) Highway Coach like a Prevost without even a little bit of input from a friend or local bus company with experience to help in your decision....

First of all this is the Wrong forum to inhabit. Most of these folks know less than nothing about highway coaches, thus the Skoolie name. Low cost school buses are what they deal with, and in many cases Air brakes and many other technical issues are things they struggle to learn about. Check out and get on the busconversionmagazine.com forum for help from actual owners of converted coaches who can offer you true and factual input on what and how to proceed.

The very first thing you MUST do is to find out and write down the actual information on your bus. Just saying it's a 1999 Prevost with a Detroit Diesel doesn't mean anything at all, since for most of their history Detroit Diesel produced the legendary 2-stroke line of engines and to most when you say a Detroit Diesel that's usually assumed to be a 2-stroke engine in many different sizes and configurations. They OWNED the bus market from all manufacturers until the late 80's and early nineties until the introduction of the 4-stroke Series 60 came out.

Later on in the mid-nineties they came out with the Series 60 6-cylinder 4-stroke engine used in buses and trucks. It's also a legendary excellent engine. You need to find out EXACTLY what engine (probably the 12.7 liter Series 60 most common), since they were available in three displacement sizes, The exact model number of the Allison transmission (most common), and as much other information regarding your Prevost as you can find. You really should find a local mechanic with highway coach and Prevost experience to take a look at and inform you of what you have stepped into.

You can't ask questions seeking help without knowing Much, Much more about what your vehicle is equipped with. You don't know what you don't know and you really should seek out some local help who can visually check it out and point you in the right direction.

The Series 60's are utterly different from the previous 2-stroke engines in every respect. Least of all is the fact that the Series 60's are all basically a computer operated engine with Electronically controlled diesel fuel injectors in each cylinder. The 2-strokes on the other hand are purely mechanical in operation and will function with no battery at all. This means that the electrical system from the (2x12V 8D)batteries (total 24V by the way), for the entire bus electrical system, must be in good condition, and the various wiring harnesses, connectors, cables, and solid ground connections must all be in good condition. This is all before even considering the DDEC Computer system that controls it all. To add more nightmare considerations the DDEC relies on lots of sensors inside the engine and around the bus to read and determine what to do to operate the engine/transmission properly.

By all means you should just plan on replacing the two size 8D batteries to start with in order to eliminate them as the primary cause. From there you will then follow wherever it leads to get things to work properly. You may get lucky and that's all you need do. But trust me it won't last long because there will be many other issues that will crop up and need to be dealt with.

Privately owning a Prevost Highway coach is not the thing I would ever advise a person with no previous experience in buses or heavy trucks to do. It's one of the most intensive sure fire opportunities to go broke in every way, right after Airplanes, Boats, and Ferrari's, etc. The only thing I can say is that you have no idea what you're in for, but you'll find out very soon indeed. Where Angels Fear To Tread is the operative sentiment.

I can't urge you strongly enough to seek local assistance from a knowledgeable mechanic or Coach owner. If you plan on keeping this you MUST seek out and acquire a Prevost Maintainence Manual and Parts Manual. Also the correct Detroit engine manual once you ID exactly what's in your Prevost. Allison manual couldn't hurt either, again once you ID the exact trans model, since they are tied so intimentally with the engine. The DDEC controls both the Series 60 and Allison Transmission. This search for Manuals and technical information will be your introduction to, and a small taste of, the Byzantine nature of getting anything done on an older Coach, especially the very Proprietary Prevost Brand with all info and most parts originating from them.

If you're close to SoCal I may be able to help and get you in touch with others with Prevost experience. I myself have over 50 years experience driving, and owning bus companies, in every kind of coach, I much prefer MCI's and own one at this time plus several Crowns. Most folks start with an inexpensive school bus and learn lessons with moderate expenses, then if they are able, graduate into a Coach with some experience of what they can look forward to dealing with. In your case it's going to be brutal and expensive and shocking all at the same time. Not just the engine and running gear, you have things like Air Brakes, Air Suspension, Air Conditioning system, Electrical systems, Rust and Corrosion, accumulated lack of maintenance through the years, etc., all designed to keep Commercial Bus operators and their mechanics very busy repairing and struggling to keep them on the road to generate revenue. Been there done that.... Still doing it today....

Get on to the BCM site ASAP where you will find others with Prevosts and much exerience in Coaches. www.busconversionmagazine.com

 

[ewo1]

Another good source for learning about detroits and old busses,

Bus Grease Monkey

North America's foremost discussion and technical forum for Vintage GMC, Silversides, Scenicruiser, Buffalo, MCI, Eagle and other Motor Coaches. PD-3751, PD-4103, PD-4104, PD-4107, PD-4501 Detroit Diesel

busgreasemonkey.com

Bus Grease Monkey

Vintage bus mechanic lots of bus stuff and Detroit Diesel 2 stroke videos 71 series 671 8v71 Our Patreon Support page https://www.patreon.com/Busgreasemonkey scott@busgreasemonkey.com paypal We have a very active web forum located at https://www.busgreasemonkey.com It requires a special...

www.youtube.com

Prevost technical manuals

 

[s2mikon]

@ewo1 That link to 2 stroke Detroit's probably isn't relevant because after the mid 90's the 11.1 series 60's became the standard power plant. By the end of the 90's the 12.7 was phased in. The OTR truck people didn't like the 11.1 so it got passed off to a lot busses.

 

[ewo1]

@ewo1 That link to 2 stroke Detroit's probably isn't relevant because after the mid 90's the 11.1 series 60's became the standard power plant. By the end of the 90's the 12.7 was phased in. The OTR truck people didn't like the 11.1 so it got passed off to a lot busses.

Technically, yes your on point but I really like the way they explain and how easy they make things look. I also have seen some of his videos and if memory cells are still alive, he has worked on some prevosts too.

 

[Iceni John]

My 1990 Crown also has a DDEC Detroit engine. I STRONGLY suggest you buy a Pro-Link 9000 scanner for whatever generation of DDEC that your Prevost's engine uses. DDEC uses completely different protocols than car-type OBD systems, so they won't work at all for your bus. I bought a Pro-Link very cheaply off eBay because it had software cartridges for old 1980s GM cars, then I separately bought the correct DDEC 1 and 2 cartridge for my engine. With this I can now check codes (you probably have many stored inactive codes, maybe also some active ones which need to be resolved ASAP) and delete old codes. Because it's an electronically-controlled engine, maintaining your bus's electrical system at full efficiency is of paramount importance: if batteries get too low, the DDEC will cut out, then you'll "cease to proceed" (as Rolls-Royce would say). If the alternator isn't charging the start batteries correctly, then that's something else to get fixed first.

You should also get a good DVM/multimeter to check voltages/continuity/resistance/grounds/etc. Bad grounds can also cause a plethora of weird symptoms and frustrating faults, and it can take only one bad ground to bring everything to a halt. If the start batteries are at all suspect, just replace them now. You cannot diagnose and troubleshoot electrical faults if the power source is unreliable or sub-standard.

For the first year (or several years) it will take MUCH time, effort and money to sort out everything that the previous owner didn't do (or didn't do correctly). Remember that large commercial vehicles require a completely different level of care to a small car or pickup truck, and that will never be cheap if it's done correctly by competent mechanics. Your bus isn't a toy: it was intended to make money for a million miles or more.

Your sentence "They owned it for 4 years and started the bus once a week to get the fluids flowing and they drove it around their block they claim" worries me. That is THE WORST thing you can do to any large diesel engine. If you don't plan on getting the engine to full operating temperature (along with the transmission), then it shouldn't be started at all. It typically takes at least 20 miles to get all fluids to temperature. I just hope this well-meaning ignorance of large diesel engines hasn't caused any permanent damage.

Where are you located? Exactly what engine and transmission does it have? Does it have Knorr Bremse disk brakes? I assume it has IFS.

Good luck with it. A Prevost is the most complex of all buses, maybe even more complex than Neoplans and Setras! If you can eventually understand your bus you will be in a much better position to take good care of it, and Prevosts definitely need lots of good brand-specific care.

John

 

[AlexLasVegasBusSales]

@Crown_Guy Amen to your post.

If anyone needs any help I am a Prevost/volvo mechanic let me know.

 

[Crown_Guy]

Then you know Brother what he's in for, as we who deal with Coaches know all to well. I fear I may have frightened him off and we'll never see him again. He's committed for sure, unless he can manage to back out and look for a more reasonable school bus to start with. I truly wish him well but also question his judgement and hope he can find someone nearby to guide him and protect him from the $$$ consequences of biting of more than he can chew. Unless of course he's independently wealthy and $$$ is no object.... then by all means Swing Away.

 

[AlexLasVegasBusSales]

@Crown_Guy Absolutely right. I am confident they will want to get this coach back on the road though. Even though it may be the best yard ornament ever!