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restwzeasy · 02-17-2012, 06:06 PM

Sorry for the extra long post - I'm just trying to give as much info as possible in case it contains some info that may be helpful.

We took our 04 Revolution (with ISC 350) out of storage the past weekend after about 3 months and took a little trip (about 300 miles round trip). We noticed a stutter after about 20 minutes on the road, once we hit the highway. It appeared to happen about every 5 minutes. It would hop a little (less than 1 second) with the RPM, speed, and turbo gauge dropping just a bit and then return to normal for a second. It usually did that in sets of roughly 5. We seen this hop start slowly in about October before we put the RV into storage and when I took it to the service they told me that they found an old code from some kind of governing/limiting sensor trying to limit the speed below 25 miles. Apparently that is to protect the engine, but still let me drive slowly to a service. It would never limit me to that low limit and was usually seen on the highway once the engine was hot. Anyway, the shop in October said that they reset it and that things should be fine which it did look like for about a week. Winter was on its way and it was happening randomly with what seemed only annoyance problem so we put the RV into storage. The shop told us that unless we get another service light there is not much they can see with it happening randomly.

Well, so we took our weekend trip and by the time we got back the stutter seemed to be happening more often. I tried to identify a pattern and think it was only doing it while under load going uphill. Stepping on the accelerator all the way while slightly downhill or on flat ground didn't always cause it. The problem was still random, but I did plan to take it to a shop since it seemed to be much more frequent. While I was waiting for the turbo to cool down in front of our house on end of our trip, the engine just died with the oil and battery lights turning on. I tried cranking it, but nothing. I tried again and it started and all lights went off and gauges looked like everything was normal. The next day we took it to the service which is about 1/2 hour away and what a trip that was. Everything was fine for about the first 5 miles. However, at about 5 miles the engine light came on and the engine limited itself so that we could not go faster than about 25 miles/hr. We knew there was trouble and luckily we did get to the shop - slowly. Once there, I spoke to the service manager and then went outside to drive the RV around the block to see if anything has changed. Everything seemed normal with the usual hop. About 200 feet down the road was a stop sign onto a main road so we stopped and once clear proceeded. I accelerated and the engine died with us moving slowly in a turn with cars approaching. I tried to crank the engine 'in neutral' but nothing. It did start on the 3rd attempt which allowed me to breath again and drive around the block straight to the shop.

I spoke to the service manager today and he didn't have much good news for me. He said that it took them most of the day to try to identify the problem. He confirmed that there definitely is something wrong. They went for a trip and monitored the fuel pressure. He said once they hit highway speeds and stepped on it, the engine starved. He said that it somehow created vacuum in the fuel system and they suspect either a collapsed hose or dirt in the tank. We purchased the RV in early fall and drove it without a single problem for about 1500 miles. We did refuel near the end of our trip (about 300 miles from home), but things still seemed fine until about 3 weeks later. We reside in Canada and the RV comes from FL/GA. Does anyone have any experience with something similar? I know it is difficult to diagnose long distance and at this point I'm thinking about everything from hose deterioration, to dirty fuel, dirt in the tank, and even algea. The RV is still in the shop where they are thinking about re-running a new fuel line to the tank to see if that fixes the problem.

Appreciate all input.

KIX · 02-17-2012, 06:21 PM

I would suggest that you repost this in the Cummins(?) Engine forum. I think you would get more response.
Have you changed the fuel filter> If so, did you open the old one to look for contamination? That would be my first step in looking for the cause.

336muffin · 02-17-2012, 06:48 PM

Restwzeasy,I have a story for you. Last week we were talking to some friends of ours that were waiting to get their Cummins in a 2003 American Eagle that was starving for fuel. I told them of a very close friend that had the exact same symptoms a year earlier(in a 2003 AC Eagle)! I told them of a filter on the driver side frame rail on the inside next to the engine. It is very hard to see and locate. Also some of these have a screen on the lift pump before it gets to the two filters. This never gets checked or cleaned. One of the coach's had a fuel (third) filter in this hidden location! Look or have it checked, this saved my friends last week thousands of dollars! Hope this helps. Good luck! And let us know please.

restwzeasy · 02-18-2012, 08:15 AM

Thanks for all suggestions. 336muffin, the previous owner had fuel issues the past summer (we just purchased the RV in Sep) and his issue ended up being clogged strainer on lift pump due to hose deterioration and hose separating causing dirt to get sucked in. I called the shop last night and gave them the additional info. They are off until Tuesday so that gives me little more research time. I suspect that it will be a plugged lift pump strainer again. The detailed research the previous owner did made sure that the 04 Revolution only has 1 fuel filter. This was apparently confirmed by both Freightliner and Cummins. I'm definitely adding a 2nd filter/water-separator in front of the lift pump in the spring (easier and cheaper to replace filter than lift pump or worse off the high pressure pump). For now I'm stuck with the shop experimenting at $95/hr. The one good piece of news they told me was that the high pressure pump seemed fine.

KIX · 02-18-2012, 08:27 AM

Quote:

Originally Posted by restwzeasy

I'm definitely adding a 2nd filter/water-separator in front of the lift pump in the spring (easier and cheaper to replace filter than lift pump or worse off the high pressure pump).

I called Cummins a couple of years ago and asked about adding a 2nd filter to mine. IIRC they told me that addiing a filter in front of the lift pump was not adivised. Are you getting different info???
Cummins does have a filter relocating kit to make the single filter more accessible.

restwzeasy · 02-18-2012, 09:13 AM

Quote:

Originally Posted by KIX

I called Cummins a couple of years ago and asked about adding a 2nd filter to mine. IIRC they told me that addiing a filter in front of the lift pump was not adivised. Are you getting different info???
Cummins does have a filter relocating kit to make the single filter more accessible.

The previous owner did the research on this and I believe he found a way. The goal was to minimize the pressure drop due to the extra filter. His suggested approach was to move the lift pump to the back. He would extend the lift pump input line to the area where the current filter is (in the back of the RV) as well as move the lift pump into that area. He would add a new Parker/Racor fuel water separator with a 200 mesh rating in front of the lift pump and would leave the existing filter. Finally, he suggested shortening the line to the high pressure pump to equalize for the extra line length to the new water-separator. I'll have to find fuel pressure gauges to check before and after numbers when I do this as I definitely don't want to burn the HP pump, but changing the lift pump every 6 months is also not an option.

The 200 mesh rating on the first pump was in order to limit the strain on the HP pump. I'm not sure what the mesh rating on the lift pump strainer is, one thing I'll have to research.

As I already mentioned, all this research is thanks to the previous owner.

KIX · 02-18-2012, 01:00 PM

It would seem to me that it would be better in the long run to find the source of the contamination and fix the problem rather than work on the symptoms. If the problem this time is the lift pump strainer then you've got "proof" that an additional filter may keep the lift pump strainer cleaner but you've really not addressed the problem.

restwzeasy · 02-18-2012, 08:50 PM

Quote:

Originally Posted by KIX

It would seem to me that it would be better in the long run to find the source of the contamination and fix the problem rather than work on the symptoms. If the problem this time is the lift pump strainer then you've got "proof" that an additional filter may keep the lift pump strainer cleaner but you've really not addressed the problem.

I agree with you fully KIX. The shop is also planning to pull a new fuel line (not sure if metal or rubber) to the fuel tank or as far as they can get in order to bypass the current fuel line and see if that changes anything. They thought about taking the fuel tank down and checking it, but since it is 3/4 full they said they don't have anywhere to put roughly 110 gallons of diesel. Until they or I find the actual problem, I'm going to have to do my best in order to live with the problem and minimize the trips to the service by protecting components with that 'me' serviceable extra filter. Once things are fixed, that extra filter should not be in way if I do things right. Just a thought, does anyone know if the lift pump or anything else is different between the 1 system used during 2003-2005 and the 2 filter models used before/after?

Dirty fuel was my #1 suspect, but the thing that keeps bothering me is that we filled the tank about 300 miles before the end of our trip and everything seemed fine all the way home which included a stop for 3 days before continuing. I first noticed it about 3 weeks later when the engine almost died on me when I was accelerating from a stop sign. If this were fuel, I would have expected to see something right away after that refill 3 weeks before.

Any help is appreciated.

KIX · 02-19-2012, 07:07 AM

If you live anywhere near the NE Florida area I can hook you up with a guy that does marine fuel polishing. His business is mainly on boats but he can do mohos. I had mine done a year or so ago when I had algae in the fuel. If you're nowhere near this area call some fuel suppliers in your area and find someone that polishes fuel.
Just a thought....the system as it's presently configured has worked for many years without a problem.........my best advice is not to alter it

EngineerMike · 02-19-2012, 10:57 AM

Rest- how is the shop 'monitoring' fuel pressure on the test drive? I just looked at my ECU map and there is no pressure sensor on fuel until the high pressure fuel rail (after the Injection Pump and before injectors). They would have to have placed a pressure gauge or sensor of their own to monitor.
Problem could also be dying lift pump. Clog issues sound more endemic to your setup, but symptoms also match lift pump periodic failure.
Hope this helps.

Beacher · 02-19-2012, 11:59 AM

This sounds just like what happened with my old 2004 350 hp. On a trip it started the same thing no power and blowing black smoke. I made it to a cummins dealer and after 1/2 hour they said the pump was clogged. They showed me the pump and it looked like black jello. When I ask them what caused it they said it was from the low sulphur fuel and it's happening a lot. The black jello liking stuff was the inside of the fuel hose they said the low sulphur fuel doesn't have the lubrication as the old fuel did. So $1,800.00 later i was on the road they told me just to add a quart of oil to the fuel tank every time I fueled up. I sold that coach I 2008 and didn't have any problem after. Don't know if this helps but good luck

restwzeasy · 02-19-2012, 02:57 PM

Quote:

Originally Posted by EngineerMike

Rest- how is the shop 'monitoring' fuel pressure on the test drive? I just looked at my ECU map and there is no pressure sensor on fuel until the high pressure fuel rail (after the Injection Pump and before injectors). They would have to have placed a pressure gauge or sensor of their own to monitor.
Problem could also be dying lift pump. Clog issues sound more endemic to your setup, but symptoms also match lift pump periodic failure.
Hope this helps.

I'll talk to them again on Tuesday, but it sounded like they did hookup something because he told me numbers (which of course I forgot) in terms of what the pressure was and what it dropped to. Apparently when it stutters or dies there becomes vacuum in the fuel system.

restwzeasy · 02-19-2012, 03:00 PM

Quote:

Originally Posted by Beacher

This sounds just like what happened with my old 2004 350 hp. On a trip it started the same thing no power and blowing black smoke. I made it to a cummins dealer and after 1/2 hour they said the pump was clogged. They showed me the pump and it looked like black jello. When I ask them what caused it they said it was from the low sulphur fuel and it's happening a lot. The black jello liking stuff was the inside of the fuel hose they said the low sulphur fuel doesn't have the lubrication as the old fuel did. So $1,800.00 later i was on the road they told me just to add a quart of oil to the fuel tank every time I fueled up. I sold that coach I 2008 and didn't have any problem after. Don't know if this helps but good luck

I heard something similar before - regarding different fuel causing the hoses to deteriorate. When you say you sold the coach and didn't have problems after, do you mean the adding oil helped or your problems went away when you sold it? I hope you meant the first, because if not you are basically saying that I'm screwed?

Beacher · 02-19-2012, 04:54 PM

Sorry I didn't make that clear. I kept the coach for two years after I had it fixed and it was fine also it was sold to someone I know and he's had no problems at all. The dealer should be able to put the fuel pressure gauge on the unit and find the problem in the shop my did it under load setting in the garage.