Ether system troubleshooting

[Guruman]

It seems maybe my ether start system in inop.

I left the block heater unplugged to test if the ether was working. Seems that's a "no".

I replaced the can with a new one from NAPA. I understand the ether won't activate until it's cold, but how cold? It's in the mid teens today, and man it did not want to run...

Pressing (even holding) the ether switch did not seem to do anything. It was still just crank-crank-crank. Should I be able to hear it activate?

It finally did start, but not what I would call normal, way too much cranking then slowly firing on more and more cylinders until it would finally spin on its own.

 

[doghead]

How are you operating it? I’m not familiar with FMTVs but assuming they use the same system as most diesels you need to hold the button, let it “load” then it releases the measured shot of ether when you release the button.

 

[Guruman]

How are you operating it? I’m not familiar with FMTVs but assuming they use the same system as most diesels you need to hold the button, let it “load” then it releases the measured shot of ether when you release the button.

I tried pressing it, then cranking, holding it for a bit then cranking. Cranking and pressing it while it was cranking, and cranking it and holding it down for several seconds while it was cranking. None of that made it fire right up.

 

[doghead]

As I said, the only time ether is released into the engine intake is after you release the button. In your post, you do not mention releasing the button.

 

[doghead]

You want to release the ether into the engine while it is cranking over.

 

[Guruman]

I did plenty of releasing too. Both before and during cranking.

 

[Ronmar]

This system on the LMTV doesn’t ”load” it is direct injection from the bottle into the manifold via a solenoid valve on the canister. it works differently on the different trucks. The A1R it is controlled by the ECU automatically. On the A0/A1 it is a simple circuit, 24V from CB22(fan/ether breaker) thru the dash switch, thru a thermal switch down on the coolant bypass pipe on the A0 right in front of the head and back thru the solenoid coil to ground. I am not sure where the thermal sw is located on the A1, might be right into the main cooling plumbing Near the thermostat. The spec for the A0 switch says 90F so the coolant needs to be lower than that. I have heard the A1 sw is specced at a lower temp closer to freezing but don’t have any reference for that.

Yes, you should be able to hear the solenoid go clunk At the cannister.

if your fan solenoid is working when you cycle the main switch on and off then CB22 is intact. I would next check the thermal sw to make sure it is connected and has a circuit thru it. You can unplug and jumper across the connector easy enough.

The op manual says switch in on for 3 seconds off for 2 while cranking so about a 60% duty cycle, until the engine will run without it…

 

[Third From Texas]

I maybe just have a good nose, but I can smell the ether the scant few times I've ever tested a truck.

I don't know if there is a way to see if the bottle is full. What's the TM say?

*edit: I see you have a fresh can so n/m

 

[Guruman]

Thanks @Ronmar . I definitely could not hear it doing anything. It's too freaking cold to mess with it anymore tonight. I'll try jumping the temp sensor at some point.

 

[Ronmar]

In my A0 coolant system re-design I removed my bypass pipe where the thermal switch is placed. Since I am about to do some sensor changes in the coolant system, I dug it out and pulled that ether thermal switch out so I can get it into the thermostat housing. Looking at it, it is not the same part as is specced in the 24P. I threw it in the freezer and it closes around 35F and opens back up around 37F…

 

[BKubu]

It generally doesn't get very cold in MD. But, it does get cold on occasion. It was recently in the single digits. I've started my 1998 M1078 (with the 3116) and it always fires up. My 2007 M1085A1 with the C7 is a slower starter, but it always starts, too. I assume (and know) Indiana sees colder temps. I don't offer any starting aids, and these two trucks always start just fine...again, down to single digits. I have used ether...manually added...to my M939 series trucks. I never, ever even checked to see if the stock bottle was full. I just started cranking, while I added a sniff (a couple second blast) of ether to the air intake. And, those trucks always started. A few years back, we had a serious cold spell where temps at night were below or around zero for about two weeks. During the day, the highs were about 18 degrees...with the more regular temps around 10-12. My M925A2 started OK with a sniff of ether, again while cranking, but added manually from a can. I do not like to start any of my diesels when it is cold if I can avoid it. The few times I have recently (mentioned above), I HAD to use the truck.