C7 Won't Start!

[jcwhitty]

Hello All. I have a 2003 Itasca Horizon, with a freightliner chasis, powered by the 330 Horsepower CAT C7 motor. Two weeks ago I moved it back to storage after a trip, and it ran great. I went to take the coach for 4th of July weekend and it would not start. There is plenty of diesel (generator runs great), batteries are good and the starter motor is strong, but it never fired at all. The check engine light is not illuminated, but there is a check transmission light. I am thinking it has to do with the ignition, and maybe the ECM. Any suggestions would be appreciated.

I spoke with freightliner, and they suggested I have it towed in. They felt it would not be beneficial, or more economical to send a mobile mechanic due to the number of issues there could be to deal with. He mentioned that there were three electrical leads to the ECM and they all have in line fuses, and suggested I check those first, but he wasn't sure where those would be located since it is a motorhome. I did remove the engine cover under the bed, and believe I located the ECM attached to the motor on the passenger side. Tough to get down to check everything. Looks like it will be an expensive ordeal unless I can figure out something simple. I did check all the fuses and relays in the panel above the generator up front, and they all tested fine.
Thanks in Advance.

John Whittaker

[DriVer]

Quote:

Originally Posted by jcwhitty I spoke with freightliner, and they suggested I have it towed in. They felt it would not be beneficial, or more economical to send a mobile mechanic due to the number of issues there could be to deal with. He mentioned that there were three electrical leads to the ECM and they all have in line fuses, and suggested I check those first, but he wasn't sure where those would be located since it is a motorhome.

John, Did you call 800 FTL-HELP? That's weird that they would offer, "wasn't sure where those would be located since it is a motorhome." The tech that will answer the phone during normal business hours @ FTL-HELP will know about motorhomes.

[heavyequipt]

Have you checked for normal operation of fuel shut-off solenoid.

[jcwhitty]

I have not called the 800 number, just the local freightliner dealer here in town. I will give them a call. Also, regarding the shut off solenoid, I have not checked its operation. Since the motorhome ran fine when I shut it off, and did not even hint at firing, I am assuming that it is ignition. Would the shut off solenoid also affect the diesel generator, because it runs fine.

[JoeT]

If it cranks, I don't see how it could be an ignition issue. It doesn't have any spark plugs. All a diesel needs to run is air and fuel.
The fuel shut for the engine would be separate from the generator.

[jcwhitty]

Since I am used to working with gas, you raise a good point. To rephrase, after reading a number of posts regarding the ECM/ECU and how it can shut down the motor when receiving a signal from a sensor, I believe it is "electrical" in nature. I assume it would shut down the motor by shutting down the injectors. Gut feeling tells me that if there were something else going on, more mechanical, it would have shown symptoms prior.....but maybe not.

Thanks, I need to reprogram my brain.

John.

[Rvfeller]

If it's not turning over, I just replaced the starter solenoid!

[MaverickBBD]

John-
Call the 1.800.FTL.HELP number first before having it towed. The tecs there just work on motor home. Many worked on the line before going into the service center. FCCO if you are a member or join will get you into access Freightliner with all your drawings and wiring diagrams.

[jcwhitty]

Thanks Tom....Freightliner help was great! I was on hold maybe 30 seconds, and Rhonda was very good. I now understnad that in fact I do not have a C7, but the predecessor which is the 3126E motor, though she said they are very similar. She suggested, as did Freightliner of Portland, to first inspect the fuse and condition of the wire which supplies power to the ECM. The diffence in her response vs. theirs is that she supplied me the exact location of the in line fuse, whereas McCoy Frieghtliner in Portland had not idea where the fuse would be on a motorhome. Will keep you all posted.

John from Portland Oregon.

[jcwhitty]

Thanks to DriVer also......

[MaverickBBD]

John
When you get a chance you should consider joining FCOC and Access Freightliner. It gives you your wiring diagrams (among tons of other drawings). The 10% discount isn't bad either. You will be attending Camp freightliner in no time. Good luck and let us know what you find.

[jcwhitty]

Lastest status....pulled codes and it shows a 39, which is the IAP valve. The local CAT dealer is sending someone out tomorrow to work on it. Will keep you posted.

[MaverickBBD]

Good job. You came a long way from standing in the dark and scratching you head and having it towed. Keep us up to date.

[jcwhitty]

Happy me! CAT showed up as promised, well prepared to make an onsite repair, even to replace the pump if necessary. As it turned out, it was simply the sensor gone bad, so we are back up and smooth running! Thanks for all the assistance. Total bill: $430.00. The sensor I believe was over $100.00.