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Topic: electrical issue?? 1996 U320C fuel pump/ECM problems (Read 740 times) previous topic - next topic

electrical issue?? 1996 U320C fuel pump/ECM problems

Hi all!

We have a 1996 U320C stuck in a random shop after we got an engine shutdown light on the highway in the middle of the night in N Florida some months ago. We would really like to get it back on the road!! We hadn't previously experienced any issues with the chassis side of the RV while driving. We had had intermittent issues with the chassis batteries dying and needing a jump to start. In one instance, a jump did not work, and a mobile mechanic found an ignition wire (I think) that needed to be repaired, and we thought that problem may be solved. Still, the batteries have died twice in the time the coach has been sitting in the shop these months, with everything shut off inside the coach (including dead switch).

The diagnostic process has been a bit all over the place maybe? After making sure our batteries were the correct voltage and in good order, the mechanic determined there was a problem with the fuel system. He said it would run off starter fluid. He thought there may be a leak, but did some kind of pressure test and determined that was not it. We replaced fuel filters and the fuel pump. Still a no go. He said he did not have the ability to connect to our ECM without some kind of harness that was supposedly going to take longer to obtain than presuming there is probably an issue with the ECM and getting it repaired. So we sent the ECM somewhere for repair. When we got it back, the mechanic found some kind of grounding issue when testing out the "repaired" ECM. The RV started and then died after a few minutes and has not started again since. He did some voltage tests and determined that the ECM is not getting the correct voltage but is stumped where to go from there.

Just putting this case out there to see if there are any thoughts, or if anyone has seen something like this. I saw a thread " Topic: coach repaired; was ECM/fuel pressure/speed sensor, oil press, etc" but not much info there...

Thanks for reading!!
Tara and Tyler

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #1 –
I would check the wires going from the ECM to the battery. There are four wires going
from the ECM and then through 2 fuses to a #10 wire to a post on the frame to the battery.
I have had trouble with the fuse holders and also the connection where the four wires are
attached to the #10 wire. If those connections are bad they will let voltage through but not
enough current to run the ECM
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #2 –
There are a few threads as to findings these fuses.  I bet when Michelle has time,  she can find these threads if you don't find them.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #3 –
If you look on the top of the bellhousing/ transmission there are a couple of fuse holders inline in the wireing harness on me 99 295 they are a heavy red fuse holders. These are the ECM fuses on an ISC 350 IIRC. Yours may be in the same place.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #4 –
Quote from: turbojack –
There are a few threads as to findings these fuses.  I bet when Michelle has time,  she can find these threads if you don't find them.

I will look around for them, thanks (to all)! Was also told to look into replacing the engine harness, and will be looking for more info on that as well!

edit: think I found the relevant thread? Cummins M11 ECM Fuses

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #5 –
On a previous post you said that some mechanic ran the engine on either. If that engine crank and ran even for a short period of time you need to hunt for something other than the wiring harness. Keep posting things that have happened so we can get this figured out.
What fuel pump did this fellow replace?
Which exact engine do you have as those were the years that they were doing swap overs and was using what ever they could get.

Mike
Pamela & Mike 97 U 320

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

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #6 –
Well no answer this guy after several attempts from this week, so that I could ask what exactly is happening when he tries to turn it on these days. Various things have been replaced/repaired since then. It was a Cummins Part# 3090942 fuel pump replaced on a Cummins M11 engine.

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #7 –
That is bad when you can't talk to the mechanic.  If he replaced that fuel pump that should have had a new fuel cut off valve so unless it (fuel shut off valve) isn't getting voltage to open that system should be ok. It sure seems like there is a fuel problem like bad suction hose, clogged fuel filter either primary or secondary, not enough fuel in the tank or some other fuel related problem.

Mike
Pamela & Mike 97 U 320

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

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #8 –

As many have done in the past you are at a point that many multipliers to your original problem could have been induced .

1.  You need to establish your Start battery system is healthy
      A. Batteries have capable cranking capacity
      B. Ground cables are capable of transmitting full power. Just because you can read voltage it must be measured during cranking. I really like using a simple test light in parallel to the cable in question. If the light lights up you have resistance during cranking.
      C. Power cables same test. With the test light connected to the battery across to the starter lug the light should not light up static or during cranking.
      D slow rotational speeds will prevent starting. Do not use either for T/S starting, I was shown to use Napa contact cleaner

2.  Establish a list of start codes. Buy an engine code reader. Doesnt need to be super expensive , just enough to read and clear codes.  170$ Amazon.com: ANCEL Heavy Duty Truck Scanner HD601 All System Diesel Diagnostic...
      A. Verify ECM is powered up and fuel valve is being powered during crank cycle. Should see fuel mist/vapor out the exhaust pipe.
 
3.  Fuel.  This is equally important as everything else. Do you have an air leak? The ISM sucks fuel from 25 feet away and must have an operational lift pump. If there is any air leaking into the fuel line you will not meet the required pressures for easy starts.  Air compresses liquids dont. You have either already changed your factory fuel lines or you will be planning to change them. We all have changed them for leaking air into the lines causing poor start conditions.
      A. Does your lift pump function during the start cycle? Does it move fuel? Is there air bubbles in the fuel? Which fuel secondary filter system does your coach have? I recently finally removed my factory WINN system and went to FASS system and have nothing but good thing to say and recommend everyone to also IMO. Provides continuous fuel pressure to the engine driven pump while the engine is running and removes all air during operation if there was a air leak. FASS Diesel Fuel Systems - Diesel Fuel Pumps and Systems
Basically you're looking for three things. Fuel, air, and rotational speeds  fast enough to create combustion.

Coach wont start trouble shooting (Battery)

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Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #9 –
Maybe a silly ? back to basics, what about low coolant level in black reservoir tank or sensor? Jim.
Jim and Dona
2002 U295 36'
Lily, blue healer. Our fury person
Manx mid travel Ecotec turbo
2022 Bronco badlands Sasquatch
Trail 90 and 110cc

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #10 –
Low coolant level sensor failure will allow start and run for 30 seconds to clear roadway. Resets for another cycle when key is cycled

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #11 –
Thanks very much everyone! At the time of the incident, coolant and low fuel were not issues, but who knows by now I suppose. Supposedly the new fuel pump is not getting enough voltage to run correctly. Fuel lines were also replaced. I really don't have more details than that without asking the mechanic who won't answer the phone. We have not discussed a lift pump. I don't know if it's been examined to see what's happening there.

As I can't get it out of his shop without towing it, I am considering seeing if I can find a mobile mechanic that will go take a look at some of this stuff. Or see about towing it to the nearest Cummins place if they will take it. So wish we hadn't ended up at this shop!!

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #12 –
You do not have a lift pump.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #14 –
Quote from: tarabee –
Supposedly the new fuel pump is not getting enough voltage to run correctly. Fuel lines were also replaced.
. So wish we hadn't ended up at this shop!!

As others have stated you don't have a lift pump only the main pump you gave part number for. But this voltage thing is a problem as the fuel shut off valve needs voltage to open. This could be nothing but a bad connection. It would be nice to know if they just replaced what fuel lines they could get to in the engine compartment or did they completely go all the way and pull the fuel tank to get to those hoses. Don't feel bad as when you are broke down on the side of the road you are at the mercy of who ever you get. You would be money ahead to get the coach to someone that is familiar with a Foretravel.

Mike
Pamela & Mike 97 U 320

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

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #15 –
Where is the coach located, someone might be able to suggest a better shop, or even be able to go down and take a look at it
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #16 –
Quote from: kgrover –
Where is the coach located, someone might be able to suggest a better shop, or even be able to go down and take a look at it

in Citra, FL!

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #17 –
Quote from: Pamela & Mike –
As others have stated you don't have a lift pump only the main pump you gave part number for. But this voltage thing is a problem as the fuel shut off valve needs voltage to open. This could be nothing but a bad connection. It would be nice to know if they just replaced what fuel lines they could get to in the engine compartment or did they completely go all the way and pull the fuel tank to get to those hoses. Don't feel bad as when you are broke down on the side of the road you are at the mercy of who ever you get. You would be money ahead to get the coach to someone that is familiar with a Foretravel.

Mike

Probably just the fuel lines in the engine compartment based on the parts purchased. I think he said he'd determined via pressure test of some kind that there was not a leak in the hoses and wanted to save us money/probably also save the trouble of doing it. He was well meaning in the first place but over his head, unfortunately for everyone. Know he wants it out of there. Worried about towing it again, but we'll see if we have to!

Re: electrical issue?? 1996 U320C fuel pump/ECM problems

Reply #18 –
Google Maps

I'd give cummins a call, they are just down the road from where you are.
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246