k0ua
Epic Contributor
yes, it is the larger one in the middle
DK40SE HST No start - fuel problem? electrical?
- Thread starter tabacman
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yes, it is the larger one in the middle
ritcheyvs
Veteran Member
This should help:
I think your no-glow must be either the glow relay (most likely and least costly) or the display unit, although all the other display unit functions seem OK.
I think your no-glow must be either the glow relay (most likely and least costly) or the display unit, although all the other display unit functions seem OK.
seacap04
Gold Member
Last fall I had a hard start issue with my DK45. It would start and stall several times before it would finally run. I had very low voltage on glow plug buss bar. 70 amp glow plug relay was latching and had continuity through to glow plugs. Key switch contacts were clean with continuity were it should be. I was just about to start on the fuel system when I thought I should check load voltage going in and out of the 70 amp relay. Bingo. Good voltage going in and low voltage coming out. Replaced relay and now runs fine. This is not my first issue with the glow plug circuit. The symptoms are the same, run for a second or two and stall.
OK frustrating results on quickly replacing the preheat relay. Same no start.
Didn't have time to check the voltage at the plugs... but if I had to guess - no juice.
Anyone know how much the Timer relay runs? Or should I bite the bullet and get both that and the display unit - which looks pretty pricey - just judging by the wires it has going in and out of it.
Do all the safety switches etc. cut the actual starter motor circuit? I don't have the full diagram with me during the week... not entirely sure I would be able to tell even if I did.
I've replaced the preheat, start, and fuel stop relays so far. Getting fuel from the bottom of the tank up out of the top of the injection pump. Harness connections seem OK for all the ones I can pull up to where I can see. I guess I should check the actual connectors to see if anything weird is going on there - but no obvious indications like a wire hanging out the back.
Alright end of the venting of general displeasure - as always you guys are a great deal of help...
ritcheyvs
Veteran Member
tabacman: Do yourself a favor and do diagnostics before replacing any more parts. Do you have voltage to the glow plugs (key both on and cranking) or not? Also clarify: are you getting fuel to the injectors when you crank?
If you don't have a helper, get some long meter leads so you can connect/see the meter while working the key switch.
The MIE Kioti parts site will give a good idea of costs.
If you don't have a helper, get some long meter leads so you can connect/see the meter while working the key switch.
The MIE Kioti parts site will give a good idea of costs.
Ok cracked fuel pipe on top of injector and i do see fresh fuel.
Checked all glow plugs. No power in on or crank postion.
Seem to get power on blk rd wire into preheat controller.
Very brief spike of power on blk rd wire coming out of timer relay.
I think that timer relay needs to power longer than 1 sec.
Also i dont see that power spike at the rear glow plug where harness attaches.
I get good power on red wire out of timer relay.
I think that timer relay isnt right.
ritcheyvs
Veteran Member
OK, so you have fuel to the injectors, that's good.
I previously assumed that all the SE models used the Display Unit (photo in post 32) to control the glow relay (and also the pulse to the SS pull coil). But maybe some earlier DK40SE models use the older preheat controller (T4620-69054) (plus a timer relay) instead of the Display Unit (T2185-69872 to T2185-69875). So I will assume you really have a preheat controller (vs Display Unit) on your firewall. It is possible that none of the published DK40SE service manuals show your exact configuration (this is the case with the stop solenoid on my DK45s).
The timer relay only effects the SS, it does not effect the glow system. If your stop solenoid works OK, don't worry about the timer relay.
I'll assume your schematic is similar to the DK45s, which also used the preheat controller. In that case, the ONLY things that can prevent power from reaching the glow plugs (key in crank) are the key switch and the glow relay. The black/red wire to the preheat controller is the output to the glow relay coil. It should get power from the preheat controller before starting and for maybe 15 seconds after the engine starts (called after glow which helps the engine run smoother. This wire also gets power directly from the key switch whenever it is in crank positions. The fact you see about 12v on this wire means the glow relay coil should be getting power (i.e.. the switch and preheat controller are OK).
The glow relay is the same as the start relay. One quick check is to swap relays and see if it still cranks. Usually you can do this by just swapping the connectors (e.g. don't move the actual relays). If you get a no-crank after swapping relays you know you have a bad glow relay. These are common automotive relays which should be available at any local parts store (like Autozone).
You can also take voltage measurements at the relay connector. There are two wires for the "contact" pins (#30 and #87) which should have bigger wires. One of these should always have 12v and the other should be wired to the glow plugs. As a test, you could jumper these briefly (less than a minute) and see if you get power to the glow plugs (you should if the wires are OK). The other lugs (#85 and #86) are for the relay coil. One of them should be ground (zero volts and zero ohms) and the other should read 12v but only when the key switch is in glow or crank. If these voltages don't check out, there is a problem with the wires. With the relay unplugged, you should be able to measure 50-60 ohms between 85 and 86 and an open circuit between 30 and 87 if the relay is OK.
I previously assumed that all the SE models used the Display Unit (photo in post 32) to control the glow relay (and also the pulse to the SS pull coil). But maybe some earlier DK40SE models use the older preheat controller (T4620-69054) (plus a timer relay) instead of the Display Unit (T2185-69872 to T2185-69875). So I will assume you really have a preheat controller (vs Display Unit) on your firewall. It is possible that none of the published DK40SE service manuals show your exact configuration (this is the case with the stop solenoid on my DK45s).
The timer relay only effects the SS, it does not effect the glow system. If your stop solenoid works OK, don't worry about the timer relay.
I'll assume your schematic is similar to the DK45s, which also used the preheat controller. In that case, the ONLY things that can prevent power from reaching the glow plugs (key in crank) are the key switch and the glow relay. The black/red wire to the preheat controller is the output to the glow relay coil. It should get power from the preheat controller before starting and for maybe 15 seconds after the engine starts (called after glow which helps the engine run smoother. This wire also gets power directly from the key switch whenever it is in crank positions. The fact you see about 12v on this wire means the glow relay coil should be getting power (i.e.. the switch and preheat controller are OK).
The glow relay is the same as the start relay. One quick check is to swap relays and see if it still cranks. Usually you can do this by just swapping the connectors (e.g. don't move the actual relays). If you get a no-crank after swapping relays you know you have a bad glow relay. These are common automotive relays which should be available at any local parts store (like Autozone).
You can also take voltage measurements at the relay connector. There are two wires for the "contact" pins (#30 and #87) which should have bigger wires. One of these should always have 12v and the other should be wired to the glow plugs. As a test, you could jumper these briefly (less than a minute) and see if you get power to the glow plugs (you should if the wires are OK). The other lugs (#85 and #86) are for the relay coil. One of them should be ground (zero volts and zero ohms) and the other should read 12v but only when the key switch is in glow or crank. If these voltages don't check out, there is a problem with the wires. With the relay unplugged, you should be able to measure 50-60 ohms between 85 and 86 and an open circuit between 30 and 87 if the relay is OK.
Last edited:
Thanks ritcheyvs.
I will check the relay again... but i replaced start, fuel stop, and preheat (bigger) relays with new parts.
I think what im hearing is that i need to check preheat controller box. I have that with a separate timer relay.
The only thing left is key switch and harness wires.
My otr trucker friend suggested a shot of starter fluid w glows disabled to see if it would catch and blow unspent fuel out. Sounds dangerous.
I like the older workshop manual - way more info than the one that came w mine (2007). Thanks for link.
My wiring diagram doesnt show a display unit and i dont see in engine bay.
I was also thinking of puttin 12v separately right on glow bus connection and seeing if it caught.
I will check the relay again... but i replaced start, fuel stop, and preheat (bigger) relays with new parts.
I think what im hearing is that i need to check preheat controller box. I have that with a separate timer relay.
The only thing left is key switch and harness wires.
My otr trucker friend suggested a shot of starter fluid w glows disabled to see if it would catch and blow unspent fuel out. Sounds dangerous.
I like the older workshop manual - way more info than the one that came w mine (2007). Thanks for link.
My wiring diagram doesnt show a display unit and i dont see in engine bay.
I was also thinking of puttin 12v separately right on glow bus connection and seeing if it caught.
k0ua
Epic Contributor
Keep in mind the glow plugs draw about 60 amps. So if you do the wire jumper thing.. use a big enough wire, or you will see how a smallwire acts as a fusible link Or even a source of light and heat for a short period of time.:shocked:
ritcheyvs
Veteran Member
You can run a BIG jumper wire direct to the glow plugs from the battery positive to see if it starts. That bypasses all the glow control logic so it should start if no-glow is the root problem. BUT (1) use a big wire (maybe 10 gauge or bigger), (2) connect it briefly (like less than a minute), and (3) make sure it doesn't short to chassis ground anywhere.
You can also jumper the two big wires right at the relay connector to energize the glow plugs. That may be safer and easier.
Heed James' advice. It's pretty spectacular (not to mention dangerous) when a section of wire vaporizes in a flash.
Now, NEVER use ether starting fluid with an indirect-injection Diesel (like we have). Indirect injection engines are the type that have pre-chambers and glow plugs. I understand it's OK to use ether with direct-injection Diesels (but I wouldn't do it). Many of the big trucks are direct-injection engines, that may explain the advice you got.
You can also jumper the two big wires right at the relay connector to energize the glow plugs. That may be safer and easier.
Heed James' advice. It's pretty spectacular (not to mention dangerous) when a section of wire vaporizes in a flash.
Now, NEVER use ether starting fluid with an indirect-injection Diesel (like we have). Indirect injection engines are the type that have pre-chambers and glow plugs. I understand it's OK to use ether with direct-injection Diesels (but I wouldn't do it). Many of the big trucks are direct-injection engines, that may explain the advice you got.
