I noticed that recently our 1997 C8.3-325 was frequently taking longer than "normal" to start the first time for the day of travel. Historically, it started very quickly at the turn of the key. Recently it has frequently taken several seconds to fire up on many occasions. Coincidentally, historically, I filled the fuel tank near the end of each travel day, but recently have been postponing fill ups for a few days to take advantage of lower fuel prices along our travel route. On our most recent trip, I observed that it started immediately in the morning after a fill of the tank just before stopping for the night. If the tank was down a bit from full, the first morning start was slow. Each of these "coincidences" happened at least twice during the trip. The starting behavior shows no correlation to ambient temperatures, but does correlate directly with the level of the fuel in the fuel tank.
I plan to check with Berndt Ramspeck in NAC regarding the issue. Does any reader of the forum have experience to clarify the issue or suggest a solution?
Mine was the Winn systems air leaks then replacing all the rubber fuel line hoses that the low sulphur fuel had dried out.
Have you had your fuel lines changed out yet?
For the price of fuel filters I would change both of them.
JD,
Like others said if you have Winn I'd look at reworking it or preferably replacing it with the Racor with integrated prime pump. Great unit. Other than that, since your symptoms are obviously fuel related, checking the lines to and from the engine fuel pump might be a good call. Look at fuel line fittings as best you can.Takes a couple of fittings but not too hard to do is installing a clear vinyl line temporarily between primary and secondary filter. That'll show you if you're sucking air from a bad fuel line, fitting, pickup tube etc. Does your engine have the mechanical fuel pump or electric?
the 8.3 usually doesn't have a "Winn" system. The 1997 8.3 has a mechanical lift pump.
The problem sounds like air getting in the fuel lines or a failing and/or failed lift pump.
Do it do it with fuel tank full and engine parked downhill?
If you find cracking in the lines around the hose fittings (even if that is not the cause) wrap some Rescue silicon tape around the end tightly (or the cloth electrical tape) and that will prevent air entering and give you time to get lines changed. I did all of mine (even on top of tank) when I had a hole cut in floor for inspection just to be on the safe side-but had almost no cracks too.
Another way to stop air entering is what I did a few weeks ago on the 2 lines that come and go from Cooling system filter when it was pouring out of there while on this trip. I cut some new small diameter rubber rad' piping and sliced it down one side then wrapped it around leaking ends and used 3 clamps on each one to squeeze this new hose slightly over all the cracked area. I have done 1k miles since and not a drop of fluid lost since, so I know it would do the opposite and seal any air leaks on fuel lines. I hope it lasts till we make it home, but will at some time soon get a couple of new lines made up and change them out when I have the chance to get under the rear again.
Just and idea that does work- for me right now.
JohnH
Rescue tape and tie wraps can do wonders. Or Rescue tape and hose clamps.
All fuel lines were changed about three years at FOT. They replaced the rubber lines with plastic lines. They pulled the fuel tank and replaced all the fittings at the fuel tank.
R B Services (Bernd Ramspeck) tweaked a couple of the fittings on the fuel lines and repaired a leaking injector line about two years ago.
The mechanical lift pump was changed one year ago by R B Services.
The fuel filter is a simple spin on filter with a sight glass at the bottom. I think there is only one fuel filter. It is located passenger side near the start batteries. There is no priming or purging device in the fuel system.
I've seen no signs of fuel leaks since R B Services repaired the leaking injector line.
The coach always remains level when parked. I know it starts quickly with the tank full. It requires some cranking to get it started after sitting overnight when the tank is more than 50 gallons down from full.
FYI, I think there is a secondary fuel filter mounted on the engine...I believe on the passenger side. It often gets overlooked.
That's a tough one. If there is absolutely no sign of fuel leakage, you've got an air leak into fuel system somewhere that is allowing air to enter and fuel to siphon back to the tank. The easiest, and probably first place to check is at your fuel filters, including the drain valve on primary. You should have a secondary filter though, typically located very close to mechanical fuel pump on side of engine. Are proper gaskets installed on filters?
Does anyone know....I've heard oblique reference to a check valve in the engine fuel system somewhere. Is there such a valve?
The secondary filter is a fleet guard FS1251 FORMERLY a fs1226.
If you change these d'ont forget to fill with fuel.
yes on my Cummins it is on pass' side abpout mid pont of engine. Be very carefull there though as behind it is the wiring for ECM and the connection pins and that is what caused all my problem last winter. If you are removing it DO NOT use anything other than a thin metal strap type filter wrench.
JohnH
Thanks to all for suggestions and education. I'll seek out the "other" fuel filter so that I know where it is. I think I have spares in the coach, but have never personally changed or tweaked them.
I agree that the symptoms indicate some drainage to the fuel tank. The level of fuel in the tank would affect the "suction" on the fuel supply system when the engine is off. Drainage would require some air to replace the volume of fuel. A "less than full" tank might be required to such a bit of air into the system.
The problem is currently more of a curiosity than a "show stopper." I'm due for some services on the engine and coach. Those services will be done by people in NAC who know the systems. I'll see if the behavior changes after the filters are changed.
You may laugh at this but see if the fuel tank in the mornings is under suction?
Mine had non vented fuel fill caps on it. Overflowed up steep hills from the pressure buildup and after the hot fuel cooled off the tank was under suction from the reduced volume.
Needs to be a vented cap as far as I know.
I believe the OEM fuel cap is non vented. When I fill up while travelling I hear/feel the pressure in the tank release.
Roland
Mine shot fuel out after going up cajon pass and out of grapevine, ca with non vented caps.
Same hill, vented caps, no overflow and smells and fuel all over the road.
No idea what was supposed to be there but as I drive mine harder than most those were my results.
Bought two new locking vented caps and the overflow isdues went away.
The first thing I would have checked is the fuel return check valve on the injection pump.
TORK TEK CUMMINS ADJUSTABLE OVERFLOW VALVE OFV010 - Tork Teknology (http://www.torkteknology.com/products/TORK-TEK-CUMMINS-ADJUSTABLE-OVERFLOW-VALVE-OFV010)
The first thing I would have checked is the fuel return check valve on the injection pump.
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Yes I agree high failure rate on oem return fuel line check valve. I replaced mine with the following...
I just checked the engine compartment from above using a small flashlight to illuminate dark areas. I found the secondary fuel filter high on the side of the engine, toward the front (of the coach), on the passenger side. I could see no evidence for fuel leakage anywhere on the engine or fuel systems.
The only designation on the fuel tank caps was "Diesel Fuel Only." I saw no holes in the cap, but I think they may be vented. In the section that screws into the filler pipe, there appear to be some ports in the molded plastic and there may be some kind of venting system. The tank never "exhales," nor "inhales" when I remove a cap. It must be vented somehow.
After I get the engine started one time during the day, it starts very quickly thereafter. The only "slow" starts appear to be after the coach has been idle overnight with a partial tank of fuel. That situation takes a long time to reproduce. We'll see what happens with new filters installed by experienced mechanics. I will also inquire about check valves in the system that might affect the starting issues.
Thanks for contributing to my continuing education.
Any change in starting habits usually goes hand in hand with either air being introduced into the system or a restriction. Overnight system pressure drop could also be related to a fuel return valve but less likely. A DOA heated intake screen is another possibility if you have one. A tank of fuel with a low cetane rating will make for poor cold morning starts as cooler weather approaches and may contribute to slower starts.
Anytime a coach is driven up a relatively steep incline with a tank less than half full, it should be fast idled for a couple of minutes to insure no air has been picked up in the tank before shutting down. This has caught several members.
Pierce
When I helped tear apart a 2000 u270, I finally got to see the vent. It comes along the front bulkhead right in the middle of the coach. It was a small hose with a screen on the end. Never would have seen it, but the entire front end was gone and converted to a 5th wheel.
Our U300 vent is set for 2-4 psi so has a fairly good "whoosh" when the cap is removed.
Pierce
JD,
A longer crank time after it sits makes me think that fuel is leaking back from the engine toward the tank requiring more cranking to bring the fuel back.
If you have changed your fuel lines that should eliminate that.
Did this start since the last fuel filter change? Oil filters have a check valve to keep them from leaking down, l'm not sure if fuel filters do. If this started after the last filter change you might consider changing them again. Save the ones you take off if they are new and don't solve the problem.
JD
If your 295 has aqua hot their is a one way in its fuel supply line I am told.
If the aqua hot lines are cracked and the one way is bad then fuel can be sucked from the engine.
Not an expert on the exact connections in there and I may have mis stated exactly how it's hooked up but something to consider.
I noticed the change when I started allowing the fuel level to stay at lower levels overnight. I can't correlate the slow starting with a change of filters. I can correlate the slow starting to a change in my habits.
It is time for oil and filter changes. We'll see what happens after the fuel filters are changed. I also plan to describe the symptoms to Bernd. He may check some things during the service event.
J.D., you wouldn't necessarily see any fuel leak, when the coach is idle the lines are under suction, not pressure. Any small leak, air can come into the lines, letting fuel drain back to the tank. A low tank increases the problem. Sounds like you're going to be getting your filters changed anyway, if this doesn't cure the problem then the "banjo bolt" on the return side of injector may, as others have suggested, be the culprit. If you do end up replacing this relatively inexpensive part, I'd suggest replacing with one that's tapped to allow a pressure gauge to be inserted or installed. It's possible to tap the stock Bosch part, or purchase an aftermarket unit that is already tapped. If the old one is worn enough to leak down, a new part will probably give you some additional power also.
I know what you mean though. I really like the fact that my C8.3 cranks up instantly, it's like switching on an electric motor.
A leaking lift pump on mu 95 280 with the 8.3 created the same symptoms that you are describing. An alert mechanic while rebuilding the bracket for the hydraulic pump asked if I would like him to replace the lift pump while the welded bracket cooled off. I told him to go ahead and all the symptoms disappeared. As a side note he apologized when he charged me $38 bucks an hour for labor for the whole deal, wish he was still alive and I still had a FT.
Gary B
Here is an interim update on the C8.3 starting issue.
The primary fuel filter was filled with "black stuff." The bottom of the fuel tank was covered with "black stuff." The fuel tank was inspected with a camera and LED on a flexible stalk. Bernd showed how my tank looked compared to another tank that was mostly clean on the bottom, but with some "black stuff" in the corners. In the "clean" tank, we could see reflections from the bottom of the tank, as well as the top surface of the fuel, as the camera was lowered into the tank. In my "dirty" tank, we could see no reflections from the bottom of the tank.
The plastic primary fuel line installed at FOT a couple of years ago had a kink in it at the fuel tank.
The fuel tank has been pulled and cleaned. The primary fuel line will be replaced from tank to primary filter with a new flexible hose.
Bernd thinks the "black stuff" and kinked fuel line are significant contributors to the starting issue. It still puzzles me that the engine starts quickly on a full tank of fuel, but takes 15 seconds to crank at 1/3 full. The slight pressure differential from full tank to partial tank apparently has an effect. The engine has performed well after the first start of the day. Subsequent starts during the day were usually rapid. The issues noted above needed to be fixed. We'll see how things work after I retrieve the coach.
We've had the coach about 5 1/2 years. I've been careful to keep the fuel tank full when the coach is parked. I've bought fuel from high volume stations. I've tried to buy fuel with the least percentage of biodiesel, depending on availability. Between "real" trips, I've driven the coach 20 miles or more every month to exercise and lubricate the systems, and circulate fuel. In spite of that care, we've got a lot of "black stuff." My research indicates that the ULSD fuels are more likely to accumulate "black stuff." Biodiesel is more likely than petrodiesel to introduce water into the system. Biological invaders are more likely to cause problems when the is more water and less sulphur in the fuel. I plan to start using some fuel treatments to avoid the "black plague."
Other issues that are being addressed include: cleaning/treating some rusty areas while the fuel tank is out; replacing a "shrunken" exhaust manifold, cleaning/treating some rusty areas around the radiator and engine compartment; adding some electrical cable to enhance cranking power from the chassis batteries. I plan to report on a couple of those issues in a different thread.
We get the same "Black stuff" in turbine airplane fuel tanks and it is a growth. Some airplanes have Strontium crystals inside that are changed at intervals as they get used up. In time it corrodes the aluminum fuel tanks. Water is held in suspension in kerosene/diesel/parafin etc. and the growth thrives on it. They use stuff called "Biobore" to clean it out. One application and it evaporates. I would suspect your fuel source.
I cannot answer why it starts better with a full tank although fuel hoses comes to mind from other posts??
Brian
It's actually a bacteria growth,is common in the lousy fuel they get on the offshore platforms,been up many a night changing
fuel filters every hour because of the black stuff.
I always treat fuel with a lubricity/cleaning additive. If stored for a long period of time, I add ILFC 1032. ILFC Ten32<br/>Fuel Inhibitor<br/>Storage Stabilizer, Lubricant — Internation... (http://www.ilfcinc.com/ilfc-ten-32/)
I found information about Biobor here: Biobor Jf Fuel Additives - Products (http://www.biobor.com/products/biobor-jf-fuel-additives/) Biobor was the only additive that I found that has a MIL-SPEC qualification. The specification appears to be primarily related to "stabilization" of diesel fuel. However, the manufacturer claims that it is also effective as a biocide and enhancer of lubricity.
My research indicates that some of the "black stuff" may be asphaltene, a precipitate from degraded diesel fuel. Many of the fuel treatment products claim to "stabilize" diesel fuel, kill microbes, and improve lubricity. I plan to choose an additive and use it regularly. My previous attempts regarding fuel "hygiene" appear to have been inadequate.
If somehow you got some in your tank and/or it grew or got bigger then when/if your additive killed it,its got to go somewhere
and it went in your filters.We would get 500 gal.tanks of diesel on the platforms and for whatever the reason some would be full
of the black junk and some would not.
What I'm trying to say is when you treat it and kill the bacteria it will still be in your tank.
JD, did it look like this stuff? I found this in my primary filter last December.
Good info on the forum for recommended biocides if one searches for biocide (particularly any post by wolfe10 (aka Brett Wolfe))
We use it when getting diesel that will be in our tank for more than a month. Then run engine, genset, and AquaHot before sitting to get biocide-treated fuel into all systems.
Of course as John says, if you discover it in your tank, even if you kill it you're going to have to filter the dead bodies out, so it may take several filter changes.
If you can see it in the bottom of the tank, I would recommend you tilt the coach over toward the filler and using a small pump, suck all you can out, drive it a mile, tilt it over again and repeat the process. Cheaper and faster than changing a lot of filters. Then new filters on the generator and engine with several spares available. Check inside of tank frequently for remaining algae on both sides and bottom.
Like I said before, there is not a lot of quality control on diesel once it gets to the service station. Best not to fuel from an above ground tank as daily changes in temperature can cause moisture in the air to condense on the sides of the tank, go to the bottom and provide an interface for algae to grow. Less likely on an underground tank with very little temperature change but old tanks, algae in supply tankers still cause problems.
Pierce
My 1996 U320 fuel tank has a vent tub at the front centre of the tank which goes over the propane tank and out through the front wall and down behind the front tires.
Not sure if there is a screen on it.
I checked and my fuel caps are vented. I could blow air through both in and out.
Not sure why caps are vented, perhaps PO put them on, when there appears to be a vent tub.
Wyatt,
Your vent may have pressure relief valve set at about 3 psi to avoid tank damage from overpressure. Easy way to tell is after driving for while, remove the filler cap and if you get a puff of air, the vent has a relief valve in it. Ours is like this.
Pierce
I put non vented locking caps to replace the existing ones.
I probably drive my coach harder than whoever installed these as a hard push up steep grades caused fuel overflow out of the vent tube.
Changed to vented locking caps and no more issues. Tanks were full minus 10-15 gallons when they overflowed.
There was a screen on the end of the vent tube on the 2000 u270 that I was under a few weeks ago.
Cummins sells an asphaltine dispersant under their fleet guard label---- it works great and will greatly extend the time period between filter changes with the low sulfur fuels. It keeps the asphaltine in suspension in the fuel instead of clumps in you filters and tank bottom. I have used it with great success.
http://www.cumminsfiltration.com/html/en/products/fuel/additives/asph_cond.html
Hi All,
I have used Opti-Lube products. They now have a biocide type fuel treatment.
Raymond
No, this the filter did not look at all like that. The "black stuff" looked like a fine black powder. There were no clumps or chunks, and there was no slime. The fuel in the sight glass on the bottom of the filter was clear. There was an almost imperceptible layer of the black power on the bottom of the sight glass. I did not see it until Bernd pointed it out to me.
The filter was screwed on very (too) tight. The mechanic removed it by piercing it with a big screwdriver and using that as a lever. When he pierced the filter, the fuel that came out look like very thin used engine oil. There were no clumps or slime, but the liquid was black. It appeared that the primary filter had captured almost all the black stuff that reached the filter. I think the filter was not clogged because engine performance was good all the way to the shop.
I expect to retrieve the coach next week and will provide more information on what was done to clean the fuel system. I expect to also find out if the "slow start" behavior has been fixed.
We used big racor cartridge filters where you could see the element ,the whole element was black from top to bottom.
sometimes you could get by by just changing the primary filter.
I also use a larger Racor 1000FH filter with a cartridge element, very quick and easy to change.
My coach had similar symptoms as some of you describe. The biggest being that the coach was VERY difficult to start after sitting in place for two weeks. It was like it was empty of fuel. On occasion, I would pull into a fuel stop and fill up and it would still be hard to start. I never was stranded by the problem but when I returned to Michigan I stopped in for service at Cummins Bridgeway and mentioned the problem to the mechanic who was doing the service. He said it sounded like a bad spring on the fuel return from the lift pump and decided to check it. The spring (as I remember was about 1 1/4" in diameter and maybe 2 1/2" long. I asked the price for a new spring and the price was ridiculously high. He said that he could probably fix the old spring by stretching it out a little if I desired. We did that and it has been working fine for a lot of years. I recently developed the same problem again so I will be getting a $50 fix that I just read about on this particular message link. My coach just turned over 260,000 miles so things are probably getting a little tired, I guess.
Regards,