Need Help getting L345DT started

[Jeeprrz]

Hi all, I'm hoping someone can tell me what we're doing wrong because I feel like we're just being dumb or missing some issue. My dad has a Kubota L345DT tractor that he purchased a couple years ago. It was running when he bought it but it smoked quite a bit. We did some compression tests last year and determined there was at least 1 valve not closing all the way. So we pulled the head and over the winter my dad cleaned up the carbon, lapped the valves and inspected for any warping, etc. Everything turned out pretty good and we put it all back together this spring.

We can not get this thing to fire. We've set all the valve lashes to spec, I'm 95% certain it's all correct. It sounds good when it turns over. We had issues bleeding the fuel, but after a bunch of time we're getting fuel at all 4 injectors but I'm not sure if we're getting ENOUGH of it to crack the injectors open? Cylinder one if I crack open line on the injector while cranking it over fuel shoots right out, but on cylinders 3 and 4 or sort of just pulses out without as much force.

The other issue we've had is with glow plugs because this thing has been hacked up electrically and the plugs were getting a full 12.6v and they seem to have failed. We tried some off brand ones because we couldn't find any others that would come quickly. We actually just blew the resistor in the glow plug "lamp" because we put too much voltage through (had the battery charger on it). SO we have another one of those coming.

But surely we're doing something wrong or missing a potential issue somewhere. We're not getting so much as an attempt at firing, no smoke out the exhaust, nothing. Just cranks and cranks and cranks.

Any help would be MUCH appreciated, this is the first Diesel we've worked on but we're both fairly mechanically inclined and it seems pretty straight forward. Thank you in advance!

PS - if anyone has a link to some decent glow plugs we should replace the cheap ones I think as well.

 

[North Idaho Wolfman]

Did you use an OEM head gasket?
Have you done a compression test after the head work over?
You won't get it to fire if you don't have working glow plugs.

NGK 6926 Y-106V Glow Plug

NGK 6926 Y-106V Glow Plug - Same Day Shipping. PayPal Accepted. Secure Online Ordering. Est. 1969.

www.ngk.com

Local auto parts store should have them.
Start there and get back to us with answers.

 

[Russell King]

The dealer will be able to get you the glow plugs and they will be NGK brand. They should be around ten dollars each unless they have increased the price a lot.

Are you sure the decompression knob and system is closing well?

You may want to replace the injectors and crush washers beneath them if it doesn’t start when you get the glow plugs working.

The wiring to the glow plugs is strange until you understand what is going on with it. Assuming the wiring is not too badly hacked up, you should have a key switch that simply turns the tractor on and supplies power to a knob switch that turns left for glow plugs and right for the starter to spin the engine. From that switch one wire goes to the glow plug indicator, then electricity flows through the indicator which is really a resistor to drop the voltage to around 10 to 11.5 volts. Then there are two wires connected on the glow plugs working side of the indicator. One goes onto the glow plug buss to provide power to all the glow plugs. From the knob a wire is also going to the glow plug indicator and is the second wire on the glow plug indicator but does not pass through the indicator but is connected to the glow plug buss. So the glow plugs should never see the full battery voltage. The glow plug indicator drops the voltage or the starter drops the voltage to the glow plugs. But the glow plugs are powered in both positions of the knob.

Oh and the wiring diagram shows the glow plugs are in series but they are really in parallel (all are grounded at the block and provided power at the top).

 

[Jeeprrz]

The dealer will be able to get you the glow plugs and they will be NGK brand. They should be around ten dollars each unless they have increased the price a lot.

Are you sure the decompression knob and system is closing well?

You may want to replace the injectors and crush washers beneath them if it doesn’t start when you get the glow plugs working.

The wiring to the glow plugs is strange until you understand what is going on with it. Assuming the wiring is not too badly hacked up, you should have a key switch that simply turns the tractor on and supplies power to a knob switch that turns left for glow plugs and right for the starter to spin the engine. From that switch one wire goes to the glow plug indicator, then electricity flows through the indicator which is really a resistor to drop the voltage to around 10 to 11.5 volts. Then there are two wires connected on the glow plugs working side of the indicator. One goes onto the glow plug buss to provide power to all the glow plugs. From the knob a wire is also going to the glow plug indicator and is the second wire on the glow plug indicator but does not pass through the indicator but is connected to the glow plug buss. So the glow plugs should never see the full battery voltage. The glow plug indicator drops the voltage or the starter drops the voltage to the glow plugs. But the glow plugs are powered in both positions of the knob.

Oh and the wiring diagram shows the glow plugs are in series but they are really in parallel (all are grounded at the block and provided power at the top).

Thanks for the detailed reply, the wiring is indeed hacked up, lol. The previous owner more or less gutted it. However I believe the glow plugs to be wired correctly, essentially the 12v supply (hot) wire comes through a momentary switch then to the indicator/resistor and then to the first glow plug, then feeds each glow plug in a daisy chain configuration. So I think this is wired correctly as is and was working before because the tractor started and ran, even though it's not exactly how it was wired from the factory. I do think it would be worth us getting the NGK glow plugs though.

 

[Jeeprrz]

We're going to get the NGK plugs on the way, local parts place doesn't have them in stock but can get them in a few days. Gotta find our compression tester and then we'll do that as well.

In the meantime, is there a way to test the injectors before we buy new ones? If i recall they aren't cheap so it'd be nice to only replace them if necessary

EDIT - Actually I found the injectors at Oregon Fuel for $75 each, we might just get new ones so we can eliminate that as the issue.

 

[Russell King]

You can test the injectors somewhat.

You are basically testing to see the spray pattern. Take out one injector line and turn it so it it pointed out into some area with space below it. Then bleed it and install an injector on that line pointing down and away from where you are standing. Then using some thick leather or chemical gloves, hold a piece of cardboard a couple of inches below the injector tip, crank engine and observe the spray pattern. As I understand it there should be a fairly fine mist in a fan or circular pattern. If it is large droplets or a dribbles then the injector is bad and needs repair or replacement. Then just go through all the injectors testing the same way.

DO NOT get your hand into the spray, it is high pressure and could be injected through the skin and cause many health issues.

One injector will be different than the others due to the excess fuel bypass fittings that have the small hoses attached. You may have to use the ones on the tractor that you have but they are easily removed and placed where needed.

I have not seen any discussion on what to do with the excess fuel passage during the testing above but I would try to use tubes to direct it away from the spray tip.

Good Luck

 

[D2Cat]

On those engines my experience is it takes longer then one thinks to get the air out of the fuel system. Be patient when bleeding the system, don't let the starter run but 20-30 seconds, the rest a bit. Need to let the starter cool a bit, then do it again. When you think "surly this think will start now" bleed it a couple of more times!!