Loss of Power CAT C10

[Ilvmygt]

On our last trip out we lost power while driving on a flat road. It would only go about 20 MPH. It acted like it was not getting enough fuel. The engine did not stall or miss, just no power. We got off to the side of the road.

The ScanGauge did not show any codes and NO Check Engine light. If it went in to limp mode I would think it would have a code and a light. It felt like it was not getting enough fuel.

While on the side of the road I put the coach in Drive, with the brake applied and floored it. It made about 10 pounds of boost but responded poorly, it didn't rev freely. Unfortunately I didn't think about looking a fuel flow while doing this test. It was started and shut down several times while evaluating the problem

Since I didn't have a specific cause for the loss of power I changed both fuel filters. After the filter change I redid the “Drive, with the brake applied and floored it” test and the engine was more response and made 21 pound of boost and was more responsive. Drove the rest of the trip without any problems. We were shut down on the side of the road about 80 minutes.

With no Engine Codes it would seem like fuel flow problem and I thought the fuel filters might be plugged. However the Fuel Filters had only about 500 mile on them. Maybe a bad load of fuel or the fuel tank is rusting would cause the filters to plug.

The filter change went pretty normal. I don't have a fuel shut off valve at the primary filter and the fuel drains from the tank freely while primary filter is off. This time was no different.

I was able to cut the filters a part and they look we clean to the naked eye. I was expecting to find the primary filter to be full of some thing. There was no significant amount of rust in the primary filter bowel.

Using a video probe to inspect the fuel tank through a vent line nipple. As best I can see the inside of the tank it looks good with the exception of where fill nipple was welded. There is some rust on one side of the nipple where it was welded.

The ECM has some fail safe functions. If the oil sending unit was intermittent and sent a 0 PSI to the ECM, would that force the engine to go to limp mode or shut down to protect the engine? Wouldn't that set a code?

Is there another sensor that could cause loss of power? But if so wouldn't set code or Check Engine light?

The fuel system is simple. The fuel goes from the tank to the primary filter (30 micron) then to the mechanical transfer pump on the back of the engine. From the transfer pump it goes to the secondary filter (2 micron) then to the injector pump. The injector pump has a return line to the tank.

I heard that some early 2000 MAGNAs had defective fuel lines and have posted on the County Coach forum asking about that.

Looking for ideas on things to check.

[Tha_Rooster]

If I read your problem correctly when you changed filters the problem went away?

[Ilvmygt]

Yes the problem went away. However when I cut the filters apart I expected to find them dirty and they appeared to be clean

.

[Tha_Rooster]

Originally Posted by Ilvmygt

Yes the problem went away. However when I cut the filters apart I expected to find them dirty and they appeared to be clean



Attachment 385786.



Attachment 385787

There has been post about fuel gel maybe that could be the problem?

[Ilvmygt]

The day the problem occurred was in the high 40s or low 50s which seems high for a fuel gelling problem. Also when I changed the filters the fuel ran out of the primary filter housing while the filter was off.

[Ted DuPuis]

I'd just keep some more spare filters and keep driving it. My guess is that you got some water in the fuel and that was your issue. Water won't mix with diesel, it'll settle to the bottom of the tank. You'll have correct fuel pressure and flow, but because some of that "fuel" is water, the engine won't run well on it and you won't be making horsepower or boost. By changing out the filters you may have gotten that water out of it.

You might not get a check engine light on a diesel either. The Cat ECMs keep a number of faults internal that don't necessarily generate a check engine light, but the only fault in that condition that I would see potentially providing a check engine light would be low boost/boost unresponsive for full throttle. Even then, I don't know if the ECM has diagnostics to determine that.

[CLKimmel]

The other thing to check besides fuel flow is air intake. Is your air filter clogged or any of the air lines between the filter, turbo and engine leaking?

[Rob_M]

Maybe your exhaust brake stuck for a bit.

[Onyrlef]

Originally Posted by Ilvmygt

On our last trip out we lost power while driving on a flat road. It would only go about 20 MPH. It acted like it was not getting enough fuel. The engine did not stall or miss, just no power. We got off to the side of the road.

The ScanGauge did not show any codes and NO Check Engine light. If it went in to limp mode I would think it would have a code and a light. It felt like it was not getting enough fuel.

While on the side of the road I put the coach in Drive, with the brake applied and floored it. It made about 10 pounds of boost but responded poorly, it didn't rev freely. Unfortunately I didn't think about looking a fuel flow while doing this test. It was started and shut down several times while evaluating the problem

Since I didn't have a specific cause for the loss of power I changed both fuel filters. After the filter change I redid the “Drive, with the brake applied and floored it” test and the engine was more response and made 21 pound of boost and was more responsive. Drove the rest of the trip without any problems. We were shut down on the side of the road about 80 minutes.

With no Engine Codes it would seem like fuel flow problem and I thought the fuel filters might be plugged. However the Fuel Filters had only about 500 mile on them. Maybe a bad load of fuel or the fuel tank is rusting would cause the filters to plug.

The filter change went pretty normal. I don't have a fuel shut off valve at the primary filter and the fuel drains from the tank freely while primary filter is off. This time was no different.

I was able to cut the filters a part and they look we clean to the naked eye. I was expecting to find the primary filter to be full of some thing. There was no significant amount of rust in the primary filter bowel.

Using a video probe to inspect the fuel tank through a vent line nipple. As best I can see the inside of the tank it looks good with the exception of where fill nipple was welded. There is some rust on one side of the nipple where it was welded.

The ECM has some fail safe functions. If the oil sending unit was intermittent and sent a 0 PSI to the ECM, would that force the engine to go to limp mode or shut down to protect the engine? Wouldn't that set a code?

Is there another sensor that could cause loss of power? But if so wouldn't set code or Check Engine light?

The fuel system is simple. The fuel goes from the tank to the primary filter (30 micron) then to the mechanical transfer pump on the back of the engine. From the transfer pump it goes to the secondary filter (2 micron) then to the injector pump. The injector pump has a return line to the tank.

I heard that some early 2000 MAGNAs had defective fuel lines and have posted on the County Coach forum asking about that.

Looking for ideas on things to check.

Sounds to me as though you solved the problem, I wouldn't overthink it. I used to always leave the fuel running when I chsnged the filters on my boats V12-149's, I'd let it overfolw the canister then tighten it down, that say I knew there was no air in the system.

[wolfe10]

Originally Posted by Onyrlef

Sounds to me as though you solved the problem, I wouldn't overthink it. I used to always leave the fuel running when I chsnged the filters on my boats V12-149's, I'd let it overfolw the canister then tighten it down, that say I knew there was no air in the system.

Careful here. Primary fuel filters in most on-highway applications are on the SUCTION side of the pump. With engine running, you will just suck a bunch of air into the fuel system.

[Rob_M]

Originally Posted by wolfe10

Careful here. Primary fuel filters in most on-highway applications are on the SUCTION side of the pump. With engine running, you will just suck a bunch of air into the fuel system.

Exactly. Letting fuel keep running out allowing it to fill the filter is possibly draining the fuel line between the filter and pump.
Edit: Not sure if we’re talking about gravity while not running or filling while running or key on. Either way doing so with filter loose is probably introducing air on a DP.

On a Cummins, The proper way to do it is cycle the ignition key several times leaving key on for 15-30 seconds each cycle allowing the electric pump fill the filter before starting. CAT may be different.

[Ted DuPuis]

On Cats it depends. On my 3126 there's a manual lift pump you can use to prime. If I only change one filter, I can sometimes get away with not priming manually. If I change both the engine filter and the water separator, I definitely can't. But my general procedure is just to use the primer pump anytime I change a filter.

[Tha_Rooster]

Originally Posted by Ilvmygt

The day the problem occurred was in the high 40s or low 50s which seems high for a fuel gelling problem. Also when I changed the filters the fuel ran out of the primary filter housing while the filter was off.

Fuel will come out once filter is removed. So have one ready to go prefilled or not.
There is a little pump handle on side of filter housing to prime.

[wolfe10]

Originally Posted by Tha_Rooster

Fuel will come out once filter is removed. So have one ready to go prefilled or not.
There is a little pump handle on side of filter housing to prime.

Yes, if the level of the filter head is below the level of the fuel in the tank, fuel will continue to run out until it reaches the level of the filter head. But, this is actually better than if the filter head is above the level of fuel in the tank. Because in that case the fuel will all flow back to the tank leaving you with 25+ feet of AIR in the fuel line!


I am a big fan of installing a ball valve on the inlet to the primary fuel filter. Turn it off to change filter, then open it before tightening the new filter in place to "prime".


And, yes, on chassis with Caterpillar engines where the chassis maker chose to spend the few extra $$ to install the Caterpillar filter head with manual primer pump, that made priming very simple. Just install the filters dry and use the manual pump to prime. Never an issue.