Community Forums

Skip426 · 09-19-2018, 07:37 PM

I'm late to the party on this one and would ask for some clarification .

The engine quits after 15 + mins of run time , BUT will re-start 5 hours later , for another 15+ mins of run time ; with nothing done but sitting for the 5 hours ?

That sounds like one of three things ; fuel tank not venting , or plugged ( collapsing ) fuel line or #3 read the link below! . Now my old chassis doesn't vent the tank ; at least not very well : removing the fuel fill caps after running for hours requires a wait for the venting, before the cap comes off; as per warning on the caps .

I'll add the connections at the filter strainer location in the post linked , exist on my coach and I have no idea if there was ever the strainer there , due to fuel system mods by previous owners. But with a problem like the OP is having every possibility has to be explored.

If there was rust in the tank, from sitting , it would suck in and plug engine filters long before , it bothered the gen set fuel , because the gen set fuel pick up is many inches above the bottom of the tank.

http://www.irv2.com/forums/f26/the-t...er-328852.html

DanKathyC · 09-21-2018, 08:57 AM

one quick thought in a seemingly unrelated direction, these things use engine oil to pressurize the injectors. oil of the proper viscosity, cleanliness, level? may run for a bit, oil thins down with initial heat, level goes down as the top of the motor fills up?

kketterling · 09-25-2018, 09:49 AM

I would hook up a gauge and check your fuel pressure when running till it dies, to see if it slowly looses pressure. I had a unrelated problem with mine, stuttering under a load, thought it was pump related. Put gauge on and proved it was not starving for fuel, ultimately identified a bad injector.

Quick way to check if it's fuel related when it dies.

10EC · 09-26-2018, 04:53 AM

Quote:

Originally Posted by pawpawboyce

fire up my c7 has the one engine fuel filter which is a buggar to get to unless i loosen the bedroom screws and go in from the top and that is just about as bad if you're working alone. On the rear of the coach is another filter oem perhaps by freightliner. The brand is alliance with a water detection screw to release water. This situation is frustrating, if i could drive to a qualified mechanic off i would go. i'm positive it will shut down in route. Towing is so expensive including dropping the drive shaft to avoid transmission damage.

One last thing i haven't done is to drain and clean the diesel tank completely. Only this holding me off on this is i have run the cummins generator up to 5 hours off the same fuel tank. Thanks to you, country bill, gatorcq, desertdd,
for your comments and help. I feel we have narrowed it down to 2 things: An engine problem perhaps caused by electronics or something, or just bad fuel and trash.

you know that cat does have a field service. If it is a problem you cant find they can probally diagnois it for you. My service call took about 10 minutes and cost like $250.00. Bad heui pump.
Just a thought ,, good luck

twinboat · 09-26-2018, 05:05 AM

How did it run before the filter change.

If it ran as it does now, you may be getting a lot of help with the wrong problem.

For proper troubleshooting, you need to start at the beginning of the trouble.

Cat · 09-26-2018, 02:02 PM

Quote:

Originally Posted by Skip426

I'm late to the party on this one and would ask for some clarification .

The engine quits after 15 + mins of run time , BUT will re-start 5 hours later , for another 15+ mins of run time ; with nothing done but sitting for the 5 hours ?

That sounds like one of three things ; fuel tank not venting , or plugged ( collapsing ) fuel line or #3 read the link below! . Now my old chassis doesn't vent the tank ; at least not very well : removing the fuel fill caps after running for hours requires a wait for the venting, before the cap comes off; as per warning on the caps .

I'll add the connections at the filter strainer location in the post linked , exist on my coach and I have no idea if there was ever the strainer there , due to fuel system mods by previous owners. But with a problem like the OP is having every possibility has to be explored.

If there was rust in the tank, from sitting , it would suck in and plug engine filters long before , it bothered the gen set fuel , because the gen set fuel pick up is many inches above the bottom of the tank.

http://www.irv2.com/forums/f26/the-t...er-328852.html

Maybe beside the point, but its a bad idea to remove the primary screen/filter. The primary screen filters out the 10 to 15 micron particles. What happens is these larger particles get to the secondary fuel- 2 -5 micron filter. As the pressure differences between outside the filter increases higher than the after filter pressure as the filter does it job. This pressure differential causes the large pieces to be pushed through the filter media. This causes the fuel system to fail because of contamination. Most engine manufacturers had to request that an additional filter to be added to prevent fuel system failures. CAT on some of the in dusty conditions require 3 filters on their common rail fuel system. If you replaced the secondary 2-4 micron filter and wanted to limp home by removing the primary filter temporarily ok. But not for ever. Safe travels.

10EC · 09-28-2018, 02:42 PM

Hey cat,
pawpawboyce said the other (presumaley the first in line) filter was a " alliance" is that not a water/filter seperator?

Mine was a freightliner item, cat could not touch it. I was told it was water seperator. All primary and secondary cat systems i ever had i could get both filters from cat. I have never seen a cat filter ith a glass bowl on it. Old farm tractors, yes, but not a cat.

Just wondering....

AITG · 09-28-2018, 09:20 PM

Super simple way to check the fuel tank vent: run the engine until it quits. Remove the fuel cap and listen for air rushing in (partial vacuum - you may have to pull on it). If you hear that, you have a plugged fuel tank vent. That's usually a cheap and easy fix.

CountryB · 09-30-2018, 05:07 AM

Quote:

Originally Posted by Cat

Maybe beside the point, but its a bad idea to remove the primary screen/filter. The primary screen filters out the 10 to 15 micron particles. What happens is these larger particles get to the secondary fuel- 2 -5 micron filter.

The problem seems to be that the filter is not in an obvious place (hidden, and not mentioned in the Owners manual). If I had one of these filters, I would remove it and install a new primary filter in a more accessible location.

Cat · 10-01-2018, 11:59 AM

Quote:

Originally Posted by 10EC

Hey cat,
pawpawboyce said the other (presumaley the first in line) filter was a " alliance" is that not a water/filter seperator?

Mine was a freightliner item, cat could not touch it. I was told it was water seperator. All primary and secondary cat systems i ever had i could get both filters from cat. I have never seen a cat filter ith a glass bowl on it. Old farm tractors, yes, but not a cat.

Just wondering....

The chassis manufacture puts the Alliance filter on. And there is no CAT replacement for it. It is or should be a filter water separator in one.
Moving the filter to a new location is a great idea, just remember the lift pump is already sucking it through 38 feet of hose- that makes it hard on the pump and can create it's own problems- like running out of power on long hard pulls. Safe travels