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!

 

[Jerry/MT]

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!

I don't know whether your fuel suppy is checked or not because I don't know the details of the fuel system. I'm merely suggesting that your fuel supply maybe draining back and the 4 sec crank time maybe caused by repriming the injector fuel delivery. Make sure that your fuel fittings are all tight so that you don't suck air into the fuel lines. Open the bleeder screw(s) on the filter(s) and make sure there is no air in the filter(s).

The only other possibility is improper starting procedure where you don't wait long eneough for the glow plugs to preheat the combustion chamber. As sensitive as you are to this problem, I doubt the latter is the case. It's possible the glow plug timer or the plugs themselves are faulty. Have you checked that? Just because they changed the timer doen't mean it is OK or that the glow plugs are OK. Has this been a problem since day one or has it just started?

What was the ambient temperature at the tractor whe you tried the start that went 6-8 seconds? If it was relatively cold, it reminds me of my Ford 4610 when the block heater is off in cool weather.

 

[mwb]

Same problem starting it last night and it was cold - about 5 deg C - and it cranked for seven seconds to start after a full cycle of the GP.

I measured the GP resistance, supply voltage and voltage rise as the GP heated - everything looks good. The dealer checked the same and they said that the timer was "slightly out of spec" and changed it.

I had also checked for leaks, pressure tested the supply line, flow test and everything is good. Dealer confirmed the same.

The temp for the 6-8 second crank was near 10 deg C; GP shouldn't even be required at that temperature (well even my F250, 7.3 requires GP at any temp). The supply pump is electric so even if the lines emptied back to the tank it would have time to refill - unless there is an air lock between the supply loop and the IP. I will change the supply line to a clear Tygon to test for a while.

This problem has been getting increasingly worse, sometimes (now rarely) it fires up very fast like nothing is wrong. I am baffled because I am familiar with diesels and I am well aware of the problems that air leaks can cause (my ford with the DB2 pump is very sensitive to this).

 

[Jerry/MT]

Same problem starting it last night and it was cold - about 5 deg C - and it cranked for seven seconds to start after a full cycle of the GP.

I measured the GP resistance, supply voltage and voltage rise as the GP heated - everything looks good. The dealer checked the same and they said that the timer was "slightly out of spec" and changed it.

I had also checked for leaks, pressure tested the supply line, flow test and everything is good. Dealer confirmed the same.

The temp for the 6-8 second crank was near 10 deg C; GP shouldn't even be required at that temperature (well even my F250, 7.3 requires GP at any temp). The supply pump is electric so even if the lines emptied back to the tank it would have time to refill - unless there is an air lock between the supply loop and the IP. I will change the supply line to a clear Tygon to test for a while.

This problem has been getting increasingly worse, sometimes (now rarely) it fires up very fast like nothing is wrong. I am baffled because I am familiar with diesels and I am well aware of the problems that air leaks can cause (my ford with the DB2 pump is very sensitive to this).

The only thing I can think to do is to crack an injector line prior to a starting attempt and watch for fuel while someone cranks the tractor over. There should be fuel available at the injector right away. If there's not, something is causing the fuel to drain back. (I'd have to suspect the pump at this point because it's udownstream of the injectors but with this new a machine, the pump does not have a high probablility for problems.) Check all the lines, one at a time. You'll have to wait for some time to allow any potential drain back to occur before testing the other injectors.

How do you use your tractor? Have you followed the manufacturer's recommendations regarding air filters, fuel filters etc? Are you working it in a dirty/dusty environment? Is your airfilter relatively clean and is there a delta P sensor on it to tell you if it's getting clogged? You say that sometmes it fires right up. Anything different about the ambient conditions , or the length of time between uses, etc, that will give you a clue as to why that might be? Is your fuel control via hydromechanical controller or is it a digital electronic controller like your Ford 7.3l?

This is a pretty baffling situation because diesels in reasonable mechanical condition are pretty reliable starters except at low ambient temps and even then, with starting aids, they start well as long as they have fuel and they turn over.

 

[alltoys]

Just a dumb question but are you cycling the glow plugs long enough?

On mine I have to cycle the plugs for at least two cycles at 20 seconds and it starts immediately. My temps get down to -40 and with plugging it in I still have to cycle the plugs.

You can cycle the glow plugs by engaging the pto, depressing the clutch and turning the key to the crank position. The safety switch will not allow the tractor to crank with the PTO engaged.

 

[mwb]

Well, it's back at the dealer now (actually it has been there for five days now). I told them that I am not in a rush for it - I just want it fixed. They have confirmed that there is a problem - the last time they changed the GP controller, tried it once and said it was fixed.

They are replacing lines and fittings on the fuel supply side. I have a suspicion that it's the high pressure side that's the problem though!

 

[uphere]

Just out of curiosity, your dealer - is that the fella south of Ottawa ... in Halville (McLoughlin?) ... if so, how have they worked out so far?

 

[shakin]

is that a common rail motor or does it have an injection pump.

 

[mwb]

Dealer is in Hallville. I am very happy with their customer service and I would recommend them.

This machine has an injector pump. My fear is that the IP is the problem (under warranty though).

 

[tractorbarry]

tell them to pull the glow plug rail of and remover all the paint around the the holes. there is no contact from the wire to the plug's

 

[Tul01]

good to see ya back Tractorbarry.