Newbie needs some ideas

[MNM1009]

I recently purchased a 86 m1009 completely stock (24v) system w/6.2
it does have a plow but that is not the issue. Last week it started hard, not being plugged in I thought that was normal... ( used for plowing snow in Minnesota) drove normally about an 8 mile trip. And shut off plugged in heater for overnight and would not fire next morning... Now for the list of what was done

1. Added power service 911 and added fuel (was very low on fuel)
2.replaced fuel filter and bled out hopefully doing so properly following procedures in Tm.
3.have fuel flowing to inj pump and fuel coming out of return on top of inj pump
4. Cranked over with pink wire off fuel inj pump with one bank of glow plugs out
5. Replaced all 8 glow plugs and also have 24v at each glow plug connector when light is on....
not sure what to do next....short of checking compression in cyl
last resort is to grab the carb spray and see what happens. Lol I really love this truck tho!

 

[Warthog]

You need to check the voltage at the pink wire on the injector pump. Also you need to check to see if you can hear the fuel shutoff clicking when pink wire is reattached.

Do NOT ever use ether on a diesel that has glow plugs. Bad and expensive thinks can happen.

 

[MNM1009]

Thank you for your response warthog! I have 11.45 v at key on and 11.36v at cranking and yes i can hear the relay upon plugging and unplugging pink wire. I understand what the results may be with carb spray....but this is my first diesel and it's hard to get away from gas engine ideas lol. Kind of at wit's end

 

[Warthog]

Do you have access to an infrared thermometer?



I'm just wondering if the GPs are actually heating up.

Watch the Glowplug Video in the GP Operatioal Theory sticky. It covers how the GP system should work.

You said you replaced the GPs. What plugs did you use?

 

[MNM1009]

No I don't..i suppose I can pull a gp and ground housing to see if it heats up...I just assumed ( I know what happens upon assuming) that with 24 v at the connector I should be ok

 

[MNM1009]

I used ac delco 60g's

 

[doghead]

Nope. you need to test each one with an ohm meter. 1-3 ohms is good(wire disconnected).

Complete troubleshooting is covered in the -20TM.

If they were connected at the time you measured voltage, they should be reading around 12v.(if they are all good).

 

[Warthog]

Glowplug lesson for today.

The 60gs are 10 volt plugs. The way the system is designed is that 24v (NATO requirement) is fed to the large resistor pack on the firewall and then to the GP relay. When the GP closes, the 24v is fed to the plugs.

With the resistance at the resistor pack, the ~1.5ohm resistance at each plug and with them heating up, the total voltage will drop from 24v to about 11v at each plug. More than that and the plugs will suffer. If a plug goes bad then the others will see more voltage. Another dies and the voltage increases again. Finally the last "good" plug will see the entire 24v and will die a painful death.

Since most of us will never need to meet NATO requirements, many will remove the resistor pack and rewire the GPs for only 12v.

 

[MNM1009]

Thanks dog head not sure where to find the -20 Tm but I do have 24 volts at the connector of the gp's when they are all plugged in...not sure how to measure resistance.... From the connector lead to??

 

[hndrsonj]

Thanks dog head not sure where to find the -20 Tm but I do have 24 volts at the connector of the gp's when they are all plugged in...not sure how to measure resistance.... From the connector lead to??

At the top of the main page under technical manuals.

 

[doghead]

All the technical maunals are free to download at the top of the page(main menu bar).

To measure the GP ohms, one lead on the blade terminal and the other on the hex portion. wire off for test.

If your reading 24v with the wire connected to the GP, your GPs are burned out.

Has anyone replaced the GP relay lately? (it could be the wrong one, causing complete failure of all GPs.)