DK40SE HST No start - fuel problem? electrical?

[tabacman]

OK so right around 300 hours on my DK40 and after a pretty rough winter the beast won't fire. Mines probably in the 2008 vintage (I'd really have to check the book).

I'm reading a lot of fuel related issues....
My symptoms are a little odd though.
It will crank like crazy but won't light off.
Dash lights all seem to indicate correctly and the fuses in the cab are all good.
Got fuel and indicates for neutral - and cranks over strong - so this has got me wondering if something in the fuel delivery is broken. But I've learned over the years electrical is a good suspect to line up first.

Taking a quick glance at the electrical diagram I didn't see if a relay is directly indicated for fuel pump. I know the mechanical injector pump seems to be the common point of failure from what I am reading in here.
Is there a relay I should check/replace first before disassembling the front of the block?
Is there a tank pump that sends fuel down to the injector pump that I should check out?

I just discovered my dilemma after being busy with other things the last month or two - so other than fuses and checking the real obvious things - gear selector position etc. - I haven't dug in yet.

I'm not the worlds greatest mechanic - but I'd like to at least suss out the source before I get my nearest dealer/repair shop involved.

THanks all for any help you can throw at me.

 

[k0ua]

Does the fuel shut of solenoid operate? It works this way, it has 2 coils, a pull coil and a hold coil. The pull coil pulls over 20 amps for 1 second, a timer is started in the display unit and the timer controls the fuel shut off relay on the firewall. The relay drops out after one second, and the second winding on the fuel shutoff solenoid which draws less than an amp and is powered thru the key switch buss holds the solenoid operated. The fuel shutoff solenoid is located on the front of the injector pump.
The relay that operates the pull coil is notorious to fail. The oreilly part will work fine. It will never fire a lick if the shut off solenoid is not operated. If the fuel shut of relay on the firewall does not operate the solenoid, then no fuel will flow in the injector pump because the shut off solenoid is not operated. Makes some checks and get back with us.

 

[k0ua]

Oh, the start relay (left most relay on the firewall) and the fuel shutoff relay (rightmost on the firewall) are the same relay, and you can swap them. If it wont crank anymore if you swap them, then you will know the relay is bad, or you can take voltage readings. The glow plug relay is bigger and is the one in the middle.

 

[ritcheyvs]

You should be able to hear the fuel shutoff solenoid make a distinct click when it retracts as you turn the key from off/accessory to run/preheat. That's where I'd start. Also, you will get similar symptoms if the glow plugs don't heat. You might be one of the unlucky few with a failed injection pump. But start by making sure the start solenoid functions OK. That's the easiest to check and cheapest to fix.

 

[TJP89]

As others have said, check the electrical start components, I was about to say check the spark plugs, but then I remembered there aren't any:duh: I've had the some symptoms on an older gas tractor where the distributor was the problem.

Unfortunately the first thing that occurred to me was the infamous injection pump, this sounds suspiciously like that. But check the electronics first.

 

[ritcheyvs]

As others have said, check the electrical start components, I was about to say check the spark plugs, but then I remembered there aren't any:duh: I've had the some symptoms on an older gas tractor where the distributor was the problem.

Unfortunately the first thing that occurred to me was the infamous injection pump, this sounds suspiciously like that. But check the electronics first.

Only three electrical things effect mechanical Diesel engines like yours: (1) the stop solenoid (SS) which must retract (or be removed) before the injection pump (IP) can deliver fuel (2) glow plugs which must be powered to start a cold engine, and (3) the starter. It is obvious if the starter cranks (not the problem here), Glow plug power is easy to check with a voltmeter between chassis ground and the bus bar across the tops of the glow plugs. The bus bar should read near the battery voltage with the key in on AND crank. Finally, you should be able to hear the stop solenoid retract and also hear if it drops out after the one-second timeout (e.g. hold coil not working).

Assuming all tho electrical things are good, check fuel flow. First make sure the fuel filter is full (no air). Then I'd check for a jammed injection pump by removing the oil-fill plate and checking (with the stop solenoid retracted) for smooth movement of the injection pump rack. It should move move to the full forward position under light spring force when the SS retracts and you should be able to push it back with just finger pressure. If you find it is jammed, read the sticky at the top of this forum.

 

[blucoondawg]

Those relays are the only issue I have ever had, last time I just tapped in them with a screw driver and wiggled the wires a little and it's worked fine since

 

[tabacman]

Does the fuel shut of solenoid operate? It works this way, it has 2 coils, a pull coil and a hold coil. The pull coil pulls over 20 amps for 1 second, a timer is started in the display unit and the timer controls the fuel shut off relay on the firewall. The relay drops out after one second, and the second winding on the fuel shutoff solenoid which draws less than an amp and is powered thru the key switch buss holds the solenoid operated. The fuel shutoff solenoid is located on the front of the injector pump.
The relay that operates the pull coil is notorious to fail. The oreilly part will work fine. It will never fire a lick if the shut off solenoid is not operated. If the fuel shut of relay on the firewall does not operate the solenoid, then no fuel will flow in the injector pump because the shut off solenoid is not operated. Makes some checks and get back with us.

<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=420868"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=420869"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=420870"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=420871"/><img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=420872"/>

Thanks to all. I will be doing a relay check first and will see what happens. Unfortunately i work away during week so it will be the upcoming weekend.

Just to clarify (thx for the pics k0ua) - the relay most prone to fail is the display or the fuel stop?
I will check thru obviously - but i think my reading of the great notes here are indicative of the fuel shut off relay.

 

[tabacman]

Ok first round of checks are done.
Replaced far left start relay and i get a definite click out of fuel shut off solenoid.
Bad news is no start.
Opened oil fill cover and found i could move the rack back and forth easily. So gear train appears to be functioning.
I noticed a fainter clicking very quickly after the main solenoid noise.
So im going to replace other relay on firewall on next go at it. Seems possible to me the holding part of the shutoff party may be the problem.
Unfortunately i ran battery down so i had to quit for weekend.

Question to all (again thanks) is that fuel solenoid tricky to change out?

 

[k0ua]

Ok first round of checks are done.
Replaced far left start relay and i get a definite click out of fuel shut off solenoid.
Bad news is no start.
Opened oil fill cover and found i could move the rack back and forth easily. So gear train appears to be functioning.
I noticed a fainter clicking very quickly after the main solenoid noise.
So im going to replace other relay on firewall on next go at it. Seems possible to me the holding part of the shutoff party may be the problem.
Unfortunately i ran battery down so i had to quit for weekend.

Question to all (again thanks) is that fuel solenoid tricky to change out?

I have never done it. but I think it is easy. Just a nut on a stud. But did you take a voltage measurement? There are 3 wires, a common and the pull wire, should be energized for 1 second, ( 12 volts and high current ) and the hold wire should be energized continuously from the key buss (12 volts but very low current.)