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Topic: Engine losing power (Read 1044 times) previous topic - next topic

Engine losing power

Hey there Foretravelers,
I noticed the shore power was out at our storage facility. Sure enough the coach batteries were run down. Thinking I could just recharge them with the generator during my ride I went ahead and took it out.

Drove about 25 miles to my destination and noticed the rpms dropped upon exiting the highway. When I got to the red light the coach was non-responsive to the pedal even though it was running. I turned it off and restarted and was able to get it to my destination at low mph by short little spurts from the pedal.

I went ahead with my business (son's tennis tournament) and left the generator running for about 4 hrs. When I came back the engine started right up and was driving much better but about 10 miles down the road started sputtering on the pedal again but I managed to keep it about 55 mph. I tried putting it on cruise control a few times but it didn't seem to make that much difference.

When I exited is when big problems started all over again. Unfortunately I had a long string of red lights where each time it either died or the pedal became unresponsive. Had to kill and restart to get the coach to move. Sometimes several times per intersection.

I made it back to the storage facility out of sheer stubborness.

Thankfully, I already had an appointment booked at MOT for next week right after TG. But not sure I want to drive it like this all the way from Dallas, especially not knowing what the problem is.

Question: Any ideas what this might be?

Thanks,
Mike



2003 U320 3820 Designer Series

Re: Engine losing power

Reply #1 –
How much fuel is in the tank and when were the fuel filters changed,try less expensive things first,top the tank off and change filters and use some diesel additive and go from there,don't even think of going to MOT like that.Mike,the batteries will charge from the engine alternator when driving no need to run generator just to charge batteries.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Engine losing power

Reply #2 –
Mike,

What was chassis battery voltage when this occurred?

House battery voltage?

While fuel issues are more likely, since this occurred immediately after batteries going dead, worth a quick check.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Engine losing power

Reply #3 –
If it idles OK but does not take fuel well when you try to leave an intersection, it's the filters in most cases.  When the engine is stopped for a while, the debris falls to the bottom of the filter but then clogs the filter again. Usually runs the best for a little while in the morning before driving far.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Engine losing power

Reply #4 –
Mike your ISM is electronic controlled and fuel injected. I would think that the operational voltage would be quite low since all takes place during starting with lower than normal operating voltage while cranking. I would think you are involved with several symptoms at once and may or may not be related to battery voltage. Indicated voltage may also be different than actual. I would chase fuel restrictions in combination to charge and capacity issues. If both are good then fuel air leaks.
Scott

Re: Engine losing power

Reply #5 –
Yep, everything is on the table now. Still waiting for a shop to let me in to look for it.
Jim
Jim Frerichs
2002 U320 42'

Re: Engine losing power

Reply #6 –
Hey guys,
I can't thank you enough for responding and coming up with some suggestions. It is most appreciated!

John,
We were down to 1/2 tank. Fuel filters were changed end of Jan 2020. I've been using Sta-Bil stablizer at each fill. Can you add too much? Possibly kicking up junk into the filters? Thanks for opinion/reality check to not try to take it to MOT. I've got to take it somewhere as I am not handy or proficient with this kind of work. My local shop here in Dallas doesn't do chassis work but I might call and see if they can do a quick look to see if it might be something easy or that I may have overlooked.

Brett,
The short answer is I don't know because currently I'm not sure I know how to measure that the correct way. I did check the ProSine display which was at 13.75V battery status while the generator was running and could turn the cabin lights on after I turned the generator off and switched off the chassis battery when I got back before plugging into shore. I will look into fuel issues as you and others have recommended.

Scott,
Yes, I can see how I have confounded the problem by presenting the coach battery issue but couldn't help but wonder after they were run down. I was told by JJ at Blue Moon that he didn't think the display was providing proper incoming voltage. Thanks for bringing up the ISM and possible fuel air leak. I will take yours and Brett's advice to check electric, then go to fuel.

Many thanks!
Mike
2003 U320 3820 Designer Series

Re: Engine losing power

Reply #7 –
No, you can't use too much additive. Does not make any difference when you changed filters. A tank of bad fuel can clog new filters.

Outside change your lift pump may have gone bad.

If you have proper voltage when the engine is running, it's not the batteries that are causing the lack of power.

Change the filters if battery voltage OK.

There is a reason I put a pressure gauge on the discharge side of the secondary filter. Also, on the intake side of the primary.

Also the reason I put dual voltmeters right in front of me so I can instantly tell if any voltage problem.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Engine losing power

Reply #8 –
The voltage displayed on the Prosine is the HOUSE BATTERY BANK.

It is the CHASSIS BATTERY BANK that supplies the Allison and Cummins computers.

Best is to start with your digital voltmeter at the chassis batteries when this happens.

Be sure that terminals are clean and tight.

And, if the chassis batteries are low, use the boost switch to "add" the house bank to the chassis batteries.  Even if the alternator is not working, run the generator which powers the inverter/charger to charge the house bank.  With the boost switch on, that will charge the chassis batteries as well.

Again, not suggesting this IS the problem, but really easy to eliminate at zero $$.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Engine losing power

Reply #9 –
Our U300 has an OEM analog engine voltmeter as part of the instrument cluster. Does yours?

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Engine losing power

Reply #10 –
As stated, check both chassis batteries for voltage with your multi-meter, really easy to do. If they are low, pull them and take them home to recharge. Depending on age, you may need to replace them.

Fuel filters would be next. I would replace all of them, unsure how many are in yours. Also, ensure there is not any algae in there, that can mess with the fuel supply for sure.

From there, if you have a scanner, I would see if there are any codes. You may need an adapter and most generics will not ready everything. Report back when you have more info
Jason
2000 U295 36' Non-slide  ISC350

Re: Engine losing power

Reply #11 –
Thank you to all who continue to offer suggestions for my M-11 450 engine. Lots of good ideas.
Jim

2002 U320
Jim Frerichs
2002 U320 42'

Re: Engine losing power

Reply #12 –
Am confused,are Jim and RV Mike the same guy or is Jim confused?????
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Engine losing power

Reply #13 –
Me too!?
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: Engine losing power

Reply #14 –
Oh probably Jim, but then I've been reading both threads and just wanted to thank everyone involved.
Jim or am I RV Mike?
Nope,
Jim
Jim Frerichs
2002 U320 42'

Re: Engine losing power

Reply #15 –
Is your coach diesel? Could be your accelerator pedal, if it runs by air.

Re: Engine losing power

Reply #16 –
When's the last time you changed air filter?

Re: Engine losing power

Reply #18 –
Engine air filter was checked by Cummins 2 months ago -when they looked for my problem. Not dirty enough to be restrictive.

Thanks for the suggestion,
Jim 2002 U320
Jim Frerichs
2002 U320 42'

Re: Engine losing power

Reply #19 –
O sorry, mine is older and a Cat, runs by air. I did take it to Cat once in Florida and the guy assured me my air filter was to clean. 40 miles later I swapped it out anyway and waalaaa lol.

Re: Engine losing power

Reply #20 –
If you take new fuel filters off and dump out into a glass jar, you will know if its fuel tank issue with sediment because you will see the water and stuff seperate. I first got this one it has a glass type on it. I drove it from LA to West Palm Fl. And dumped out sand like I never seen. Gentlemen before me never let it go passed 1/2 tank. It has been clean ever since. As a trucker I know that's a no no lol

Re: Engine losing power

Reply #21 –
My symptoms are that it runs weil for 50-70- miles then runs out of fuel to the turbo - no turbo pressure anyway.
Jim
Jim Frerichs
2002 U320 42'

Re: Engine losing power

Reply #22 –
Tank vent , hot fuel, weak injector pump,  weak  intake hose , plugged exhaust .

Re: Engine losing power

Reply #23 –
Quote from: Jim Frerichs –
My symptoms are that it runs weil for 50-70- miles then runs out of fuel to the turbo - no turbo pressure anyway.
Jim
Wonder if the map sensor could be causing issues to under fuel? What is the most boost you see when first operating?

Re: Engine losing power

Reply #24 –
Quote from: Protech Racing –
Tank vent , hot fuel, weak injector pump,  weak  intake hose , plugged exhaust .
Tank vent could produce those symptoms. The fuel pump will actually pull a vacuum. I have a fuel filter minder to indicate hi vacuum indications of a plugged fuel filter. Easy to check by opening fuel cap check for a vacuum being present. I doubt hi fuel temperature is possible on a 60 min run this time of the year.. intake would not be temperature sensitive. Plugged exhaust would be present all the time. I have once seen a plastic bag in a fuel tank cause this. Releases with no flow then resets itself somewhere down the road to repeat. A temperature fault in the ECM could cause this. It is fuel cooled but may take a few miles to become a active fault. I would suspect it would set a fault code thou. The ISM fuel injection pump seems to be a robust pump with few failures. A failing cam position sensor may also cause faults after warm up..
Scott