CE300 electic gremlins

[t-chuck]

Here is my experience over the last year with my bus. I am hoping someone can chime in with some knowledge. I have a 2006 chasis CE300 with dt466 engine. We have had various electrical stalling problems. The first time it was a bad battery with a short. We fixed that and the bus ran fine for 2000 miles or so. 2 months ago we had a engine shutdown after 30 minutes, waited a minute and then drove another 45 minutes home. The mechanic found the clean power harness positive IDM connector was blackened a bit and blew the fuse. They bypassed the connector and it was fine for a couple hundred miles. The stalls started again. Engine just shut down, every thing else was fine, no codes, nothing odd in the logs. The bus did not immediately restart, but did within 5-10 minutes and we made it to a Cracker Barrel for the night. The next day it happened again after about an hour, then again after less than 10 minutes. We where near a mechanic and made it there.

As long as I have had this bus, I have asked several mechanics about a weird wire that was connected to the chair lift solenoid on the firewall. The wire (16 gauge or less?) started in the fuse box, just plugged into an empty fuse space. The wire went through the fire wall to a splice that went to the chair relay and to a 20amp circuit breaker on the breakers on the firewall. The circuit breaker was obviously an odd replacement since it no longer fit in the weather seal and was just hanging in the engine compartment. Nobody was particularity interested in this. I removed the circuit breaker, thinking it was just for the chair lift. The bus ran fine, but the double doors for the bus no longer closed and just flopped around while driving. I put the circuit breaker back.

The latest mechanic immediately saw a problem with this since the fuse (where the circuit breaker was put in) is the IDM fuse and wiggling the connections choked the engine. So he removed the wire to the fuse box and the poor connection. He found the IDM fuse in the battery box was also blown and replaced that.

He replace the battery box fuse with the 40 AMP fuse. He also replaced the firewall fuse with a 40 AMP fuse. Now if you remove the battery box fuse, the bus won't run. If you remove the firewall fuse, the bus won't run. Makes sense. He returned the bus to factory specs.

Previously, when the bus would stall it would start right back up or within a minute or two. Now I assume that I would have to replace the burned out fuse before the bus will restart.

When we bought the bus it had a 20amp circuit breaker in the battery box for the IDM. I now think these hacks were a (successful) work around to keep the bus from getting stranded on a run. If the battery box circuit breaker tripped, the bus could run on the other circuit breaker. This was obviously happening and the bus ran fine most of the time. Mechanics have immediately dismissed this since the IDM uses 30+ AMPs and could not run on the 20 AMP breaker. But the bus WAS running on a 20 AMP circuit breaker.

Some things I'd like to know are:
What is the proper fuse size for the IDM fuse on the firewall? 40 Amp seems too large for the size of the single wire connecting it since the battery box 40AMP has 10 guage wires to it.
What is the purpose of the firewall fuse, if there is already one at the battery?
Does the wiring from the battery just go to the IDM or does it connect elsewhere?
Was the weird wire causing the battery box fuse to blow, or was it helping it not blow by providing an alternative power path?

I have the 2007 wiring diagrams. I am having a hard time following them and I am not sure they apply to my 2006 chassis. I have not been able to find the 2004-2006 wiring diagrams.

Does anyone have experience with the CE300 power gremlins?

[t-chuck]

I found the iDM fuse size listed on the firewall as 10 amps. I am losing confidence in any mechanic.
Was a 20 amp auto reset circuit breaker (wired directly to the main fuse box) when I bought the bus, last mechanic removed the direct wire and put in a 40 amp fuse.
I will try a 10 amp fuse as it is spected.

[ewo1]

Having a larger than necessary fuse could potentially allow wires and connection to overheat. Once they heat up you could expect to see crazy voltage swings especially when your grounds are not 100% clean.

I would go back and open up all you batt & Ecm grounds, clean them regardless how they visually look and retest the bus again to see iff there is any change.

Also cur and replace any discolored wiring or connectors.

[sportyrick]

The stalling after an hour then again after 10 minutes seems heat related, why doesn't it do it when it's cold? Why the repeat after 10 minutes? This could be a circuit breaker as they are heat sensitive. Or a spade connection just barely making contact, firewall plug connections are renowned for that. I have become fond of conductive grease, you might try cleaning connections and applying a little of that. I think you have several things going on at the same time to send you in the wrong direction.

[QuixotryHugger]

t-chuck, don't have wisdom about your issue, unfortunately... saying hey as I'm also converting an '06 CE300 DT466. It may be mutually useful along the way to chat given the same bus, perhaps similar quirks. Godspeed getting those gremlins.

[ewo1]

Originally Posted by sportyrick

The stalling after an hour then again after 10 minutes seems heat related, why doesn't it do it when it's cold? Why the repeat after 10 minutes? This could be a circuit breaker as they are heat sensitive. Or a spade connection just barely making contact, firewall plug connections are renowned for that. I have become fond of conductive grease, you might try cleaning connections and applying a little of that. I think you have several things going on at the same time to send you in the wrong direction.

You are 100% in the right direction…electrical connections!

One thing that is greatly overlooked are relays, their contacts!
Contacts get dirty, pitted and burnt. The coil may still work when energized…cold, but when hot they do weird things!

Look at your relays and the other wires to each pole. If the wires are discolored youhave an overheating issue.

[Omnibot2000]

This is in the wrong forum. Should be in international.

While I see you have a wiring issue, don't rule out a failing CPS. I've seen them shut down engines for no reason at all and restart.

[PorchDog]

Many folks think that a DT466/360/whatever is a Detroit Diesel engine. And I would too -- looking at those letters..

However-- the DT466, DT444, are International engines. D is for Diesel, and T is for turbocharged. Good old International Harvester Corporation.

[nikitis]

Originally Posted by ewo1

You are 100% in the right direction…electrical connections!

One thing that is greatly overlooked are relays, their contacts!
Contacts get dirty, pitted and burnt. The coil may still work when energized…cold, but when hot they do weird things!

Look at your relays and the other wires to each pole. If the wires are discolored youhave an overheating issue.

I replaced all my front firewall relays in my 3 box. When I first got the bus. I knew I had electrical issues with a bad VPM but didn't know that was the cause originally. I just saw videos about the relays being common problems for people and they were 5 dollars each. The ones I replaced with have LED lights on the top which tell me if they energize which is cool so I can visually inspect them if they go bad while in use in the future. Kind of neat to have futuristic relays on a 30yo bus.

[t-chuck]

Thanks for the input guys. I'm always interested in those with the same era/model bus as well. Overall it has been a great bus. We have put about 8000 miles on it so far.

I have no idea what the school mechanics were doing with the odd additions to the wiring. I did look up how that type of circuit breaker works and found they can trip around 140 degrees. Since the circuit breaker did not fit back into the holder on the firewall (it is bigger than an ato fuse), the circuit breaker was basically hanging just above the engine. My guess is when it got hot (sun beating down on the hood and engine heating up below) the breaker would trip. That tripping may have also caused a surge on the battery box fuse and blew that as well. Additionally the butt connectors were not well done and the last mechanic could make the engine stumble by wiggling the wire.

We have put about 2000 miles on it since the last fix with no problems. Yay!

[cadillackid]

Originally Posted by PorchDog

Many folks think that a DT466/360/whatever is a Detroit Diesel engine. And I would too -- looking at those letters..

However-- the DT466, DT444, are International engines. D is for Diesel, and T is for turbocharged. Good old International Harvester Corporation.

it gets worse...


the 7.3 is simply called the T444E, (there was no named DT444E)


whereas the original DT466 was a DT466, then the electronic version came out and they called it a DT466E, then after 04 they called it a DT466.


when the 6.0 came out instead of calling it a T365E and a T275E for the 6 popper.. they became the VT(V-style Turbo). VT365 and the VT275.


yeppers International..