Cold Weather Starting Tricks ?

[peakbagger]

My SEE is currently buried under a pile of early season snow and it usually sits there all winter until spring. Normally it starts instantly but in cold conditions or in the spring it really does not like to. One of the casualties of the mouse repairs was the ether can on the firewall no longer connects up the intake tract. The can is empty but I do get a whiff of ether when its cold so there are some fumes in the can.

My normal spring routine is have charged batteries and make sure I prime the fuel system up to the filter. I then remove the air filters and spray a liberal dose of starting fluid down the intake duct. It will crank over readily and I can here the starting fluid turning it over but it takes a lot of cranking with the pedal on the floor before I get any signs that fuel if getting to the injectors. Eventually it does start and after a few minutes its running fine. It then restarts well and does so until the next spring.

I think the fuel injectors on the SEE are typical diesel injectors that are spring loaded to hold fuel until it reaches a certain pressure and then it sprays. My guess is that the injector lines are drained and possibly the injection pump is air bound. Since the pump depends on fuel for lubrication I don't think its a great idea to crank it for long periods. Of course the other issue is that the vacuum leak in the fuel inlet piping is coming back to haunt me with the higher viscosity fuel due to temperature.

The question for the group is, Is anyone aware of prepriming procedure I could use to prime the injector pump all the way to the injectors?

One thing I have considered is hook up a pressurized fuel source on one of the Tees on where the diagnostic pressure transmitter is and pump pressurized fuel directly into the fuel line upstream of the mechanical fuel pump. In theory this should eventually recirculate back to the tank. Of course if the fuel is just dribbling out of the injectors as the preload springs are not holding, I expect the fuel is just washing down into the oil. I do have to be careful as I don't know the pressure rating on the fuel filters.

 

[PETE BALLARD]

I think you have fuel system issues that need repair, it is not normal for diesel engines to loose their prime due to non-use- I would predict find and repair the defects and it should start without any problems and stay away from Bio-blend fuels when you are going to have an extended period of non-use especially in cold periods of the year.

 

[Speedwoble]

Yep, with a primed system and no fuel leaks, mine will start very quickly with no starting fluid down into the 20's. Also, placing the pedal on the floor will hinder starting(I assume you were doing that trying to get it primed.)

 

[peakbagger]

Thanks for the input. I am not sure if this is applicable as I wait for warm day in the spring before even trying, so gelling shouldn't be an issue.

I have tried the pedal in various positions over the years.

Worse case is I set up my boat tank gravity fuel system with a squeeze bulb on it to pressure prime it and then start chasing the fuel system issues again. Not like I haven't gone through that routine multiple times

 

[porkysplace]

Thanks for the input. I am not sure if this is applicable as I wait for warm day in the spring before even trying, so gelling shouldn't be an issue.

I have tried the pedal in various positions over the years.

Worse case is I set up my boat tank gravity fuel system with a squeeze bulb on it to pressure prime it and then start chasing the fuel system issues again. Not like I haven't gone through that routine multiple times

Actually gelling could be a issue come spring , if the fuel gels in the filter the paraffin wax in the fuel will remain solidified and plug the filters.

 

[The FLU farm]

When I had fuel line problems, being lazy I just sat in the seat and sprayed starting fluid into the bottom of the cover on top. Then kept squirting as needed until the fuel system took over.
One thing I've never tried is giving it more throttle than just over idle.

Oh, and I do use anti gel.

 

[TModler]

The OM352 is hard to prime correctly, because even if you do it right, it still likes to keep little bits of air in the system. It is an iterative affair. This matters most for cold start and high HP tunes.

If you are having to prime you definitely have a leak. Fix the leak and you should start right up at colder temps if your engine is in good kit.

Applying the accelerator pedal during cranking can help, but should not be needed, unless you are doing this to mimick the high idle throttle setting, which all OM352’s need at cold start. They loose about 250-300 RPM due to being slow turning when cold.

At least, that’s what I think I know.

Happy New Year.

Charles

 

[The FLU farm]

Guess I should try giving the pump a few strokes before starting the Winter SEE next time.

For some reason, the last two times I've started it, it cranks for quite a while before firing up. Of course, I may have used up the ether canister by now.
With lows below zero these days, it could use all the help it can get.

 

[911joeblow]

I put the hand throttle 1/2 inch higher than the idle stop, no prime, no ether and she starts right up down to 0 deg every time. One very very cold morning (my ether can is empty and cant remove it, stuck) I did give it a shot up into the snorkel during cranking and is fired right up. So I think you are dealing with a fuel air leak. One thing to try is to put a hair drier on the fuel filter assembly to preheat the fuel.

 

[TModler]

Air leaks in the fuel system are hard to find.

Any lines that were removed/loosened/otherwise messed with should have the crush washers replaced.

The fuel filter housings are suspect, make sure you have new, good rubber seals for the housing to seal on.

The OM352 is not self priming, you need to purge the air from the pump also. If you don’t then truck will run OK, but you will be low on power as the fuel galley in the IP will not fill fully. Some people say that the air works out of the pumps by itself, but I think that only works on the engines that came with the self priming option code...

Last but not least if you have any spots in the fuel line that have been kinked or otherwise damaged, there is a high likelyhood that you have some very small cracks in the edges of the kink. This took me a while to diagnose when I discovered it.

In all cases don’t expect to see fuel from the leak, you are looking for something smaller than that.

Or just be a redneck and throw an electric pump inline and call it good enough... (Blasphemy, but....)

C.

P.S. Engine condition (compression), starter motor condition, and Injection System condition are also big factors in cold starts. I do not use ether on my OM352a and I have never had trouble starting it, but I use a gear reduction starter...

 

[peakbagger]

Thanks for all the input. I made an inquiry of a local Unimog Expert http://www.unimogcenter.com/ (Yes he does have this much inventory although I think he sold one of the ambulances shown and a SEE). He agrees that there is most likely leakage on the suction side of the fuel system which is something I have battled from day one but thought I had licked. He did suggest that the low pressure mechanical fuel pump may need rebuilding and he also is an advocate for switching to the newer style Bosch hand priming pump (which I have done). He doubted that my injectors are stuck open but did suggest running a high dose of seafoam blended with diesel through the system to clean whatever junk is in the system. Once the cold part of the winter gets past I will set up my temporary gravity fuel system and diagnose the system again.

He has an former European Unimog Plow truck (in the left side of the photo) complete with tipper bed, sander and liquid deicing salt system to keep his steep long driveway open and uses his mint SEE for loading grit into the sander and has no issues with winter starting.

Yes the electric fuel pump idea is awful tempting

 

[The FLU farm]

He agrees that there is most likely leakage on the suction side of the fuel system which is something I have battled from day one but thought I had licked.Yes the electric fuel pump idea is awful tempting

I thought I had that part licked, too but maybe it's time to give it another checkup. A quick push on the primer pump will tell part of the story.

If you recall, I temporarily ran an electric pump on the Summer SEE, which had both icky "fuel" and leakage issues. As it turned out, placed right after the strainer it didn't do much good with the main problem being the gasket for the strainer's cup.

On the positive side, the Winter SEE holds air pressure for over a month now. But that could be because of rust plugging the leakage points.

 

[PETE BALLARD]

I know the thought is intimidating, but the reality is you need to find the leak- that is the best remedy not to add more parts to maintain and still have to fix the leak anyways. Take the fuel line off of the fuel tank and find a way to pressurize it with 3-5 lbs. Find the defect and take corrective action. Make sure you pay attention to the parts/fitting you remove- any loose ones are most likely the problem. Check all the connections and inspect all the hoses for evidence of leakage. Keep in the back of your mine sometimes the pickup tube is the problem so you might have to remove it from the tank and inspect it but I doubt it. I encourage you to jump in with both feet- remember we are all here to help you get back on the road.
it is probably something very simple to repair once you find it.
all the best- pete

 

[Karl kostman]

OK George from the Unimog center is a truly wonderful guy, very knowledgeable and honest!!! I have probably the single greatest starting aid in the entire land and it will work on virtually all of our trucks no matter brand or country of origin! Its called using either a convective coolant heater that all you do is plug in to an outlet. Cranking is hard on starters, COLD starts are hard on everything and Ether when not used properly is another destroyer of anything and everything. Get you fuel issues worked out so that is all working as its supposed to then install an coolant heat source on the engine and plug it in, you will never use Ether again!!!!
Karl

 

[The FLU farm]

Get you fuel issues worked out so that is all working as its supposed to then install an coolant heat source on the engine and plug it in, you will never use Ether again!!!!
Karl

Dang it. I just knew ​I should've built the carport somewhere close to an outlet. Guess I could use a generator instead.

 

[peakbagger]

If I was to need to depend on one for winter use I think a Webasto is the way to go. Leaving the rig plugged in all winter really chews up the juice.

 

[The FLU farm]

If I was to need to depend on one for winter use I think a Websto is the way to go. Leaving the rig plugged in all winter really chews up the juice.

Meh, it wouldn't cost that much. The rodents would chew the cord off fairly soon.
And the the Webasto would really come in handy.

 

[88FLU419]

As tmodler said air needs to be bled from the pump. There is a large hex plug about 7/8 wrench size if I remember correctly, on the front of the injector pump facing the passenger side front tire near the top. After bleeding air from the filters, crack this screw and bleed air from the pump and the engine will fire much faster no starting fluid required. Fixing the leak will solve the problem, but bleeding the air out of the pump speeds starting until you find the problem.

 

[frank8003]

Dang it. I just knew ​I should've built the carport somewhere close to an outlet. Guess I could use a generator instead.

~convective coolant heater ~ how many watts does one of them use?
There is many flavors of these.
Could also put a few 12VDC batteries in parallel and an inverter if you need AC out there.
This is a old small one of these and it will do 500 watts for quite a while.
Could be a solution for power for a convective coolant heater?


If you had power there you could just put an oil filled space heater under it, very safe but need AC. they are inexpensive and economical.

 

[Jericho]

Peakbagger ,Iam just down the road from you, dont have a SEE (yet) but i just wait till Mount Washington gets above 60 below zero and winds die down under 150 mph LOL, its the nature of the beast , Rad heater or block heater will do it !