Electrical Problem

[Dacotah]

Our 2001 Sportscoach on a Freightliner chassis has developed a strange problem. Last week when I started it in our storrage area after sitting for 2 weeks, it fired once and died, and would turn over and not fire. When I tried with the emergency start boost switch it finally started but the tach was bouncing between 0 and 750 and the voltmeter was reading about 10 volts, and the check engine light was on. After running for 5 minutes the tach settled down, the check engine light went out and the volt meter read 12 volts. I removed both group 31 starting batteries, charged them overnight, and checked the specific gravity, and found 1 dead cell and 2 weak cells. I bought 2 new batteries, gave them a good charge, cleaned all terminals and wires, tried to start the coach, and same problem... it would not fire until I used the boost switch and the tach, volt meter, and check engine light did it again!! I used my voltmeter and the batteries were getting 14.2 volts when running and 12.7 at idle. 10 minutes later same thing. I have read that the digital dash processor can cause problems, but not like this. Any ideas?? Thanks, DACOTAH

[rver98]

Why don't you give Freightliner a call at 1-800-385-4357 and explain your situation and see if they can narrow down your problem

[tims52ford]

check and clean all your ground wires

[Pusherman]

I had a similar problem on my 2000 Journey (diesel) many years ago. Turned out a control wire from the alternator was faulty. Repaired the wire and was good to go.

Symptoms were alternator gauge bouncing all over the place, ABS light coming on, and ABS clunking while driving. No issues getting it started, however.

Many times it's a very simple problem manifesting itself in very complicated ways. These diesel coaches with all the electronic controls are very sensitive to low/high engine voltage situations.

[wa8yxm]

Sounds to me like the battery is low... Most folks do not know how long it takes to fully charge a battery.. If a battery is at 50 percent and you are charging at 30 percent one would think 1.4 horus and you will be there right? WRONG, 4-6 hours is needed.

The batteries, over the winter, have been both self discharging, and discharging even more when you fire it up for the monthly run.. You have not run the engine long enough to re-charge them.. They are low.

Another issue, which I doubt is dirty terminals... That keeps my coach from starting more than anything else.. (In fact the count to date (six years) is "Dirty terminals 4, all other causes zero")

The reason I don't suspect this is the low voltage would have been fixed within a second or two as the alternator came up to speed if that was the case. The voltage remained low (10) because the battery was sucking major amps.

[dantrim]

You didn't mention what the ambient temperature was at the time. Mine did a similar thing recently, but the temperature was around zero. I got the generator started and turned on the block heater and a few hours later it started and ran normally.

[Dacotah]

Thanks to all that responded!! Since the batteries were new and fully charged, I have rulled that out along with dirty terminals. I will check for a loose ground to the chassis and look at the alternator wires. After that I will call Freightliner for help. Dantrim, since I live in South Florida, (originally from North Dakota) the ambient temperature is 80 degrees in the daytime, but I do remember using the old motor home in below zero conditions for ski trips. You are never alone with your problems on this forum, it is great!! I will report back with progress. Thanks again, DACOTAH

[Dacotah]

Last night I checked all the grounds and they were OK, same for the alternator. Today I called Freightliner and their tech, Rhonda is extremely knowledgable and suspects it is corrosion on the harness that feeds the ECM. Tonight after work I will start checking from the batteries to the 5 fuses on the harness. To be continued...... DACOTAH

[Dacotah]

Update.... Last night I found the 5 fuses and each one had corrosion on the terminals and the fuses. I tried a quick scrapeing of th metal parts with no results, so today I will replace all fuse holders and fuses, then trace the harness to the ECM connector and check it for corrosion. It seems that warm hummid climates such as South Florida with the salt air causes a problem with this harness that supplies all power to the ECM. When I replace everything I will use di-electric grease on fuses and terminals to better insulate the system....more later. DACOTAH

[dreamer]

DACOTAH,

Where were these fuses located?

dreamer.

[GWCowgill]

Dacotah, where you at in SF. I live in Homestead and have seen the corrosion problem for years. It is not uncommon here to see ground connections corroded, contacts corroded and of course the terminal connections. Good Luck on getting it straightened out.

[Dacotah]

Update.... I replaced all 5 fuses and holders which are located in the battery compartment forward of the starting batteries. Then I traced the wiring to the 6th fuse by the passenger frame rail and replaced it and the holder, then I disconected the 23 pin connector to the ECM and cleaned all terminals and resealed with Di-electric grease. Now I have the same voltage from the batteries to the 23 pin connector, but the engine will turn over but will not start. there definitly was a low voltage problem with all 6 fuses and that is now solved. I called Atlantic Freightliner in Pompano beach and they will send a tech out next Tuesday AM to put the computer on and check fault codes. The shop forman said the ISB Cummins engines can have lift pump failures or problems with the injector pump which would show up on the computer.
Should I open the fuel line to one of the injectors and see if there is fuel, if not work backwards until I find the problem or just wait and spend big bucks on Tuesday? Thanks for all the input! DACOTAH

[Dacotah]

Update....... I have now contacted Cummins and joined their Power Club which gives you a 10% discount on parts and service, and registered on Cummins Quick Serve which gives access to all engine and trouble shooting manuals on line for free. I am switching my tech appointment to Cummins for next Tuesday and on Monday I will replace all fuel filters (there are 3) and follow trouble shooting guides as much as possible before the $106.00 per hour guy arrives on Tues. In the mean time, think of all the fuel we are saving by not having the engine running!! DACOTAH

[Dacotah]

Update.... After changing the filters it took a long time to prime the system but the engine finally started. I drove to the Cummins shop and they found that the engine speed sensor was bad and after replacing it, everything is OK. This was a 3 week process; it is always a big problem when you can't get the motor going to drive to the shop. The speed sensor feeds info to the ECM, and when it fails many times the motor will not start because the lift pump gets the wrong signal and the engine looses its prime. Hope this helps others. Thanks to all who gave advise!!
DACOTAH