Power cutting out

[Balou]

Hi I have an unusual problem.

I have a 2002 Winnebago Journey with a 5.9 cummings diesel.

When on level ground I can run all day. No Problems.

When I come to a hill and give it full throttle, it will monetarily stumble like someone is turning the key off then back on.

Thoughts?

[Old-Biscuit]

When was last fuel filter change done?

[SuperGewl]

Fuel, Air filters I agree.

[Balou]

Originally Posted by Old-Biscuit

When was last fuel filter change done?

Fuel filter was changed in March of this year along with a complete service. It was doing this before the service. Rig now has 69000 total miles on it with full service records.

It feels electrical to me. The engine momentarily looses power then instantly right back to full power. It will do this a few times during a long pull up a steep grade or any situation where full power is needed.

I've tried only using 3/4 throttle instead of full throttle during a hard pull and going slower up a grade. It still does the same stumble at times no matter where the throttle pedal is positioned.

If it would quit and stay quit, I'd find the problem but it's intermittent and random as of now and comes back to prefect running condition every time so far.

[indiana journey]

Was the fuel strainer changed? The description sounds like a partially plugged strainer.
Good Luck,
Indiana Journey

[Ljwt330]

Agree that it's likely fuel related.


Your vintage coach may well have the fuel strainer that is literally buried among the fuel lines and cables that run along the chassis frame. This strainer is often forgotten and never touched after initial installation.


Look along the passenger side frame rail, on the inside, just above the rear air bag. You will see fuel lines and wire looms tied together. Buried in that mess could be the strainer.


It's in this mess, note the air bag at the bottom of the picture.


It is a Racor 1040 strainer, looks like this, and is inline with the fuel line.






If you cannot find the strainer, or it is not the issue, I still agree that it is a fuel delivery problem, not electrical.

[DancinCampers]

I would check the turbo speed sensor wire Mine fell over to the hot side of the turbo and melted, engine would run great, then not.

[Balou]

Originally Posted by Ljwt330

Agree that it's likely fuel related.


Your vintage coach may well have the fuel strainer that is literally buried among the fuel lines and cables that run along the chassis frame. This strainer is often forgotten and never touched after initial installation.


Look along the passenger side frame rail, on the inside, just above the rear air bag. You will see fuel lines and wire looms tied together. Buried in that mess could be the strainer.


It's in this mess, note the air bag at the bottom of the picture.


It is a Racor 1040 strainer, looks like this, and is inline with the fuel line.






If you cannot find the strainer, or it is not the issue, I still agree that it is a fuel delivery problem, not electrical.

The search was done, there is no fuel strainer in my system.


If its a fuel delivery problem, are you saying electrically, something is cutting off the fuel?

I've driven semi for years and know when there's water in the fuel or a filter is plugging up. I've had fuel gel up on me too from extreme cold. This does not act like that.

It's like the ignition key is being turned off and instantly back on. Not a gradual loss of power, a complete loss of power momentarily 2 3 sometimes 4 times during a hard pull.

[OldWEB]

Found this on a 'net search under "4 most common 5.9 problems". So I am assuming it might relate to yours. Can you pull off any error codes to confirm?
Good luck

4. Accelerator Pedal Position Sensor (APPS) Failure – Cummins 5.9L

The accelerator pedal position, referred to as APPS, is responsible for telling the ECM how depressed the pedal is. This controls throttle and tells the ECM to open or close the throttle body, affecting engine RPM’s. When the sensor fails, the ECM doesn’t receive a signal from the pedal, therefore not knowing what to do with engine speeds.
This problem is mostly limited to 1998-2004 Cummins 5.9’s. When the sensor fails it usually sends no signal to the ECM. However, it can occasionally flash back on and send a signal to the computer which can cause the engine to surge or lunge forwards. Driving with a failed APPS will be nearly impossible and certainly dangerous.
APPS Failure SymptomsP0121, P0122, P0222, P0223 Engine Codes

• Pedal goes dead or non-responsive
• Engine surging

Replacing the accelerator pedal position sensor is a pretty simple DIY. The APPS sensor is around $100-250 depending on whether you get an OEM or aftermarket replacement.

[Balou]

Originally Posted by DancinCampers

I would check the turbo speed sensor wire Mine fell over to the hot side of the turbo and melted, engine would run great, then not.

I'll take a look, Thanks.

In the rear of my coach, on the main frame rails, there are what looks like square fuses of some sort. They have heavy positive 12 volt wires running in and back out on studs with 3/8 nuts.

There are 4 of these in different locations. Are these thermo circuit breakers ? What do they do ? They look original. Connections are clean. Could one of these be the problem ?

[DryCreek]

What's a "cummings"?

The VP-44 in the 24 Valve engine is very nitpicky about the lift pump operating at the correct pressure. And sometimes the electronic controls fail. I would try the APPS reset first. And, it's not very difficult to watch the APPS response with a good OBD scan tool. Dropouts should be pretty obvious. In any case, you will have codes stored for either VP-44 pump controller failure or APPS out of range.

[Balou]

Originally Posted by DryCreek

What's a "cummings"?

The VP-44 in the 24 Valve engine is very nitpicky about the lift pump operating at the correct pressure. And sometimes the electronic controls fail. I would try the APPS reset first. And, it's not very difficult to watch the APPS response with a good OBD scan tool. Dropouts should be pretty obvious. In any case, you will have codes stored for either VP-44 pump controller failure or APPS out of range.

What's a "cummings"?

It's a misspelled 5.9 diesel engine. LOL

I've got the battery's disconnected with the key on. I'll try the reset and see if it helps.

It run flat ground and long mild grades just fine. It will hold 55 or 70 all day depending how I want to run. It will bury the speedometer "85" if I want to.

The throttle pedal is responsive to any position it's in.

If I run very conservatively I'll get close to 10 mpg.

The only time it acts up is on a long steep grade. I can't duplicate the problem unless I'm pulling a long steep grade.

If it had stored codes, wouldn't I get an engine service light on the dash?