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Topic: Engine surging badly at idle (Read 1912 times) previous topic - next topic

Engine surging badly at idle


We have a 1995 U320C SE that runs VERY rough (as in surging and vibrating) after start and then surges at idle when warmed up. 
After $500 worth of diagnostics at a certified Cummins place the reply was a sticking pressure relief valve in the fuel pump. 
Anyone had a problem like this and what was the fix?  Also I would like to drive it from Seattle to Oregon to take it to the Cummins folks for its service and possible fix - any reason I should not attempt this trip?

(Also we installed a new fuel filter and ran the engine on an alternate fuel source with the same results.)

We would like to leave for Oregon in a couple of days.  Any thoughts?
Stella
1995 U320 40'

Re: Engine surging badly at idle

Reply #1 –
Stella, I am not well up in the Diesel mechanics but if Cummins said it was a sticking valve in fuel pump surely that is what you need to replace, the pump???Hopefully one of the engine experts will chime in soon for you.
JohnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Engine surging badly at idle

Reply #2 –
Stella,

With your coach being a '95 do you have the mechanical or electronic M-11 with the black vale cover?
When this is happening do you get smoke out the tail pipe? 
What color is the smoke?  black, white?
When you ran the engine out of an alternate fuel source did you check to make sure that the fuel line was good?
Look for cracks at the fittings and bends where air could be getting in the system?

If you could give us some more info this may help figure out your problem?

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Engine surging badly at idle

Reply #3 –
Stella

You said you changed a fuel filter, my ISC has 2 filters.  The first is a fuel/water separator and then a finer (2 micron) final filter before the main fuel pump.  I am not sure, but if your engine has 2 filters, you might want to change the secondary filter also.

I am not a diesel mechanic, but I thought I read somewhere that you can replace just parts of the fuel pump, like the pressure relief valve, as opposed to replacing the whole pump.  This could be a much more cost effective repair/replacement as the fuel pumps can be expensive.  Ask the Cummins shop to give you a written estimate of the repair including parts and labor.

Best of luck
Ted & Karen
2001 U270 36' - sold after 12 years full timing

Re: Engine surging badly at idle

Reply #4 –
Quote from: Pamela & Mike –

With your coach being a '95 do you have the mechanical M-11 with the black vale cover?


I don't think the M11 used in the 1995 model year was "mechanical." We have a 1995 U320 with the M11 (all black) and it's definitely an electronically-controlled engine.
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: Engine surging badly at idle

Reply #5 –
We have same engine with 289,000 miles. April 28 had bad miss,took it to Kenworth dealer in Ardmore OK,they put computer on found 1 injector bad and another not performing right. Had all six replaced.
95 U320 SE
07 GMC CANYON

Re: Engine surging badly at idle

Reply #6 –
Quote from: D.J. Osborn –
I don't think the M11 used in the 1995 model year was "mechanical." We have a 1995 U320 with the M11 (all black) and it's definitely an electronically-controlled engine.

David,
Your coach is the reason we put that in there, as some had the mechanical and some like yours. There are a lot of different things that can cause this depending on which engine.
It could be mechanical or electronic and that alone will make a large difference in troubleshooting.
We went back & changed the wording to make it easier to understand what info will help to troubleshoot.
Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Engine surging badly at idle

Reply #7 –
Thanks for the inputs - here is more info....

We have an M-11 400E engine.  The mechanic who did the trouble shooting puller the diagnostics on the  computer and couldn't find anything at that end.  I assume if it was a fuel control issue it would show up then???

I would rather take it to a real Cummins service center as opposed to our local truck repair place even though they are Cummins certified.  I am concerned about driving it down the freeway for 350 miles to accomplish that.  Any thoughts?
Stella
1995 U320 40'

Re: Engine surging badly at idle

Reply #8 –
Six years ago. I had a problem with my ISL400 while away from home.  The injection pump was leaking diesel fuel and the ECU was throwing an error code.  I limped into a nearby Cummins (among other brands) truck service center.  They wanted to replace the entire injection pump (estimate was $4000), and were unable to repair the error code due to a diesel soaked electrical part (which the couln't get in a reasonable amount of time), even though they did read and look up the error code.  The diesel was coming out of a threaded plug on the top of the pump.  I asked them to try teflon tape, which has held for six years now.

I limped home, and took it to a real Cummins (Cal-Pacific) service center.  They quickly diagnosed the error code and replaced the diesel soaked part, and my total cost was $100.  I also asked about the leaking IP.  They said, had I taken it there while the leak was leaking, they would have only replaced the leaking part of the pump, not the entire assembly.  They also told me not to worry about the teflon tape fix, as it looked fine to them.
Tom Lang K6PG (originally  KC6UEC)
and Diane Lang
2003 38 U295 build 6209
2016 Jeep Grand Cherokee Summit Ecodiesel
still have tow-ready 2006 Acura MDX 
Temple City, California
Motorcade 16681 California Chapter President
SKP 16663 member of SKP Park of the Sierra, Coarsegold California
FMCA F071251
Retired electrical and electronic engineer

Re: Engine surging badly at idle

Reply #9 –
Stella,

With you having an electronic engine this is sounding more like a cam/engine position sensor going bad. If the primary side starts to fail it goes to the back up side and this action will cause it to surge/rough idle. If it is this it may not drop a code. Another member here recently had your same symptoms and I don't think theirs dropped a code when there sensor went bad.  The good thing is if you find this to be the problem a new sensor isn't too expensive.

Now remember this is just a WAG without being there to look see it first hand. It might not be much more than that if we were there.

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Engine surging badly at idle

Reply #10 –
Quote from: Pamela & Mike –
Stella,

With you having an electronic engine this is sounding more like a cam/engine position sensor going bad. If the primary side starts to fail it goes to the back up side and this action will cause it to surge/rough idle. If it is this it may not drop a code. Another member here recently had your same symptoms and I don't think theirs dropped a code when there sensor went bad.  The good thing is if you find this to be the problem a new sensor isn't too expensive.

Now remember this is just a WAG without being there to look see it first hand. It might not be much more than that if we were there.



Pamela & Mike
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4
 

Re: Engine surging badly at idle

Reply #11 –
My cam sensor went.  They get oil soaked and fail.  Mistimes the mechanical injectors electronic pulse opening the injector.

Audible misfires standing behind coach.

Well known issue.  New part cannot oil foul.

They also upgraded the internal manifold pressure sensor
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4