L2550 - Hard starting at all temps

[North Idaho Wolfman]

Your glow plugs are in spec:
You need to do a compression test.
This engine does not have rebuildable injectors, they can be tested but not worth it.
You can buy new injectors for cheaper than testing.

Pardon Our Interruption...

 

[GreensvilleJay]

yessh, 1/2 ohm so will draw 25 amps +-, EACH ! Hope you got REAL good battery 'under the hood'
OK, curious, I pull an L2250-2550 WSM and it shows the 3 glowplugs in series BUT... the GP test from NIW post shows 'tab to ground'..which would indicate a parallel circuit and 75 amps...

are there 2 different L2550 tractors ??

 

[North Idaho Wolfman]

yessh, 1/2 ohm so will draw 25 amps +-, EACH ! Hope you got REAL good battery 'under the hood'
OK, curious, I pull an L2250-2550 WSM and it shows the 3 glowplugs in series BUT... the GP test from NIW post shows 'tab to ground'..which would indicate a parallel circuit and 75 amps...

are there 2 different L2550 tractors ??

No there is not mutiple different glow plug set ups.
ALL glow plug circuits in Kubota's are parallel, exception of the very very old models.
Just have to look at the flow print and not the wire color print.

 

[GreensvilleJay]

thanks for clearing that up. sad 1st 2 diagrams are wrong... neighbour had an 'old' Kubota where gps were in series, many hours spent on that......

now I'm impressed that switch handles 75 amps !

 

[sitric]

Your glow plugs are in spec:
You need to do a compression test.
This engine does not have rebuildable injectors, they can be tested but not worth it.
You can buy new injectors for cheaper than testing.

Pardon Our Interruption...

View attachment 146237

I know it has been warned many times on this board, about "cheap" injectors. This almost seems to be, too good to be true. How does one know if they are a suitable replacement?

 

[GreensvilleJay]

curious....
17391-53000
in post #21 is $200 CDN from Kubota Canada !!!!
At $40 US ( those epay ones) ,

I'd probably try them....IF they are the problem......

 

[North Idaho Wolfman]

You've got to be careful, this is one time that the "rules" don't apply.

The injectors for this engine are not the same injectors as 95% (guess) of all kubota engines.
This tractor and a few others in the same time frame used Pencil injectors and not Cartridge injectors.

Pencil injectors typically are considered non rebuildable, even though some they have rebuilt ones.

Pencil Injectors:
It's still possible, but I've have very few bad off the shelf of these type injectors.

Cartridge injectors:
A lot of these injectors are bad from sellers.

 

[pigdoc]

One thing to keep in mind is that the D-1402 engine in your L2550 is a direct injection engine.

Since I've had my L2500, with its D-1403 indirect injection engine, I've been amazed at how easily it starts, in any weather, even the coldest.

That's in GREAT contrast to the freshly rebuilt 12V Cummins engine in my truck, which is direct injection. Below 20F, it will not start without pre-heat of the intake charge.

Just saying, you may be a victim of the cylinder head design in your tractor.

-Paul

 

[sitric]

You've got to be careful, this is one time that the "rules" don't apply.

The injectors for this engine are not the same injectors as 95% (guess) of all kubota engines.
This tractor and a few others in the same time frame used Pencil injectors and not Cartridge injectors.

Pencil injectors typically are considered non rebuildable, even though some they have rebuilt ones.

Pencil Injectors:
It's still possible, but I've have very few bad off the shelf of these type injectors.

View attachment 146287

Cartridge injectors:
A lot of these injectors are bad from sellers.

View attachment 146288

Yep, my 2850 has the same injectors, which is why I asked

 

[North Idaho Wolfman]

One thing to keep in mind is that the D-1402 engine in your L2550 is a direct injection engine.

Since I've had my L2500, with its D-1403 indirect injection engine, I've been amazed at how easily it starts, in any weather, even the coldest.

That's in GREAT contrast to the freshly rebuilt 12V Cummins engine in my truck, which is direct injection. Below 20F, it will not start without pre-heat of the intake charge.

Just saying, you may be a victim of the cylinder head design in your tractor.

-Paul

UMMMM, that's the exact opposite of what they normally do.

Direct injection engines start up without preheat and start easy.
Indirect injection engines normally require a preheat and start hard.

 

[Stinger23]

Ok, back to trying to fix this. I think the 6.7 volts I'm seeing at the glow plugs is too low to heat them. So I guess I need to chase the voltage through the circuit and see where I'm losing it. Also need to check voltage at the GP when they aren't turned on to see what I get.

What compression tester type is used on this engine?

Anybody know what this chrome thing in the pic is?

 

[North Idaho Wolfman]

Ok, back to trying to fix this. I think the 6.7 volts I'm seeing at the glow plugs is too low to heat them. So I guess I need to chase the voltage through the circuit and see where I'm losing it. Also need to check voltage at the GP when they aren't turned on to see what I get.

What compression tester type is used on this engine?

Anybody know what this chrome thing in the pic is?

Looks like a glow plug indicator.
Is it wired to the glow plugs?

 

[GreensvilleJay]

Using NIW post #23, check the wiring.
Put DVM/DMM set to volts on the glowplug 'bus' and ground
Turn key to 'start', you should read 10-12 volts.
Then put meter on battery and do same, what is the voltage ?

 

[Stinger23]

Looks like a glow plug indicator.
Is it wired to the glow plugs?

That's what I thought it looked like but this tractor has the dummy lights below the gauges which I thought meant it wouldn't have a mechanical indicator as well.

I'm digging into where it's wired to now.

 

[North Idaho Wolfman]

That's what I thought it looked like but this tractor has the dummy lights below the gauges which I thought meant it wouldn't have a mechanical indicator as well.

I'm digging into where it's wired to now.

Give me the tractors serial number.

 

[Stinger23]

Give me the tractors serial number.

Here you go.

Certainly an indicator.

 

[Flintknapper]

Ok, back to trying to fix this. I think the 6.7 volts I'm seeing at the glow plugs is too low to heat them. So I guess I need to chase the voltage through the circuit and see where I'm losing it. Also need to check voltage at the GP when they aren't turned on to see what I get.

What compression tester type is used on this engine?

Anybody know what this chrome thing in the pic is?

^^^^

Its the glow plug indicator. I believe the glow plug circuit runs through.

The wire in the indicator heats up and will become red (with enough time) and is visible through the small hole.

It can take up to 30 seconds for that to happen, but I've not had much trouble starting my tractor once it begins to 'glow' even in cold weather.

 

[Stinger23]

Using NIW post #23, check the wiring.
Put DVM/DMM set to volts on the glowplug 'bus' and ground
Turn key to 'start', you should read 10-12 volts.
Then put meter on battery and do same, what is the voltage ?

12.79v battery key off, 12.2v battery when turned to preheat, 11.2v battery when cranking, 6.2v glow plugs when preheating.

 

[Stinger23]

The indicator reads 0.78v during preheat, 0v otherwise. It does not ever glow, did preheat for 25 seconds to verify.

One side is wired directly to the key switch to the pin that says Gr or G1 maybe, it's hard to see. It's a black wire with a red stripe. The other side is grounded.

 

[North Idaho Wolfman]

The indicator reads 0.78v during preheat, 0v otherwise. It does not ever glow, did preheat for 25 seconds to verify.

One side is wired directly to the key switch to the pin that says Gr or G1 maybe, it's hard to see. It's a black wire with a red stripe. The other side is grounded.

Well there's possibly your problem 2 fold!!
#1A That model does not take a glow plug indicator, someone added it.
#1B That model did take a glow plug indicator
#2A Someone has replaced it with the wrong indicator (there is different ones depending on how many glow plugs you have)
#2B Someone has completely wired it wrong, it should not go to ground, if it was right it would be wired in series to the glow plug buss. You sure it's not wired that way?

We need to see if you have the easy checker or not.

If it doesn't have an easy checker this is right.



If it does have an easy checker this is wrong.