Not happy with 3940 starting

[mwb]

I am having problems with my 3940 not starting well when cold (i.e. room temperature). I have to crank it for minimum 4 seconds or longer before it fires; if I crank it for 4 seconds, pause, then crank again it will start immediately.

I have checked the glow plugs and fuel supply and everything looks good. Took it to the dealer (warrantly) and they said that the GP controller was slightly out of spec and changed it. Brought it home yesterday; started it this morning (9 deg C) and cranked it for 4 seconds and it started. Fuel supply flow is good, supply pressure is about 5 psi (deadhead the supply line). Machine runs awesome under full load / rpm (not starving).

Can anyone else comment on their Mitsubishi S4L2 engine starting? How long do you have to crank for?

I will call the dealer back (they are very supportive) but I would like some comparision info first.

I can't accept that this engine starts this lousy; my suspicion is that the fuel supply pressure is not consistent or that the IP pump is suspect.

 

[Dallas_Lilly]

Does it start right up when warm? or the ambient temp is warmer? If it only does it when cold that seems to be the normal. When temps start dropping (last week) me and others on this board have had to activate the glow plugs for a longer period of time than the timer allows. Here is the thread that describes that procedure.
http://www.tractorbynet.com/forums/montana/134967-3040-cold-start-problem.html

 

[mwb]

No, this is not temperature sensitive. Even at 20 Deg C it is hard to start. Once it has been running it will be fine the rest of the day. It seems to reoccur after a full cool down (overnight). It seems like it is a fuel problem but with the electric pump there should be no problem repriming. If there is an air bubble at the IP then that would be a different issue.

 

[Jerry/MT]

I am having problems with my 3940 not starting well when cold (i.e. room temperature). I have to crank it for minimum 4 seconds or longer before it fires; if I crank it for 4 seconds, pause, then crank again it will start immediately.

I have checked the glow plugs and fuel supply and everything looks good. Took it to the dealer (warrantly) and they said that the GP controller was slightly out of spec and changed it. Brought it home yesterday; started it this morning (9 deg C) and cranked it for 4 seconds and it started. Fuel supply flow is good, supply pressure is about 5 psi (deadhead the supply line). Machine runs awesome under full load / rpm (not starving).

Can anyone else comment on their Mitsubishi S4L2 engine starting? How long do you have to crank for?

I will call the dealer back (they are very supportive) but I would like some comparision info first.

I can't accept that this engine starts this lousy; my suspicion is that the fuel supply pressure is not consistent or that the IP pump is suspect.

How many hours on the engine? If it's relatively new (under 100 hours), it could be a tight engine. Four seconds of cranking doesn't sound excessive to me especially for a new diesel starting cold. Expect the cranking time to increase with decreasing ambient temps below ~50F unless you have a block heater in operation. It's also possible that your starter output is not per spec but if this is a new machine there's not a high probablility of that being the case. Is the engine oil per spec? Oil viscosity affects the starter loads. Is the fuel per the manuafacturer's spec (cetane number)?

As far as you supply fuel pressure, checking dead headed pressure is interesting but it doesn't tell you much. Put a "T in the line and measure the pressure with flow and compare that to the spec.

 

[mwb]

170 hours, oil is to spec, engine turns over very fast. Four seconds (or more) seems like a very long crank to me. If it was Janurary then this would be (maybe) acceptable but not during the summer months.

Can anyone else with this engine tell me how many "one - one thousand's" it takes for their machine to start.

 

[Dave5264]

Well, I cant help you onthe Mitsu engine, ive got a 5264, its a FIAT engine, 50 hrs on it, it starts immediately, less than a second of cranking, regardless of temperture.

 

[Jerry/MT]

170 hours, oil is to spec, engine turns over very fast. Four seconds (or more) seems like a very long crank to me. If it was Janurary then this would be (maybe) acceptable but not during the summer months.

Can anyone else with this engine tell me how many "one - one thousand's" it takes for their machine to start.

You might try tightening up the fuel lines because ther might be a small air leak or look for a faulty check valve in the fuel lines to the injector that maybe allowing the fuel to drain back from the injector lines causing you to have to reprime the injector lines on each start.

 

[Jughead3040]

i have a 3040 with mitsubishi engine...it cranks for while before is starts too, unless it is warmed up (from block heater or from running) in which case it fires immediately.

 

[blueriver]

After reading this I went to the barn to check the 4340C ... the glow plugs stay on to a count of 15 ... thats one thousand and one ... one thousand two and so on to 15.

When I hit the key I don't even get one thousand and ... it starts ... no problem here.

 

[mwb]

You might try tightening up the fuel lines because ther might be a small air leak or look for a faulty check valve in the fuel lines to the injector that maybe allowing the fuel to drain back from the injector lines causing you to have to reprime the injector lines on each start.

Out of town for the long weekend...

I don't think there are any check valves between the injectors and the IP. What check valve are you referring to?

I started the darn thing last night after being away for four days and it cranked for 6 - 8 seconds with "hit and miss" on the last few turns. I am not happy with this.

I firmly believe that it's a fuel problem; maybe I will install a check valve in the supply line to the IP. I called the dealer today and they are not sure what to do; they suggested that this is the way Mitsubishi's start!