Cold Start Issue

[JLElectric]

Even when its 50*, I have trouble starting. If I plug in my block heater it's perfect. New batteries. I have tested the GP relay. 12.5 in 10.6 out. Do I need to check the other wires on that? I checked the glow plugs by one lead on neg terminal of batt. and other lead on valve cover where the harness connects to. I checked the two outer prongs on each side. I got .7 ohms. I would think that is fine. What should I do next. What about the control module? Or if that was bad I wouldnt get power to relay, right?

[cman962]

I've been down this road before, and again currently. I am repeating what I have read on here.
Make sure the GPR is sending current for at least 30 seconds, it should be more like 1 - 2 minutes. If it is not it is getting weak and not sending voltage to the GP's long enough to heat the GP's properly.
If you need to replace it I would advise spending the money on the HD Stancor GPR. I replace mine the first time with a NAPA GPR and it lasted through 1 winter.
Hope this helps.

[dfdinc]

JLElectric I’m new to diesel repair and troubleshooting but I have worked with automotive electric for several years. From what I understand the .7 ohm's on the GP's is good. But the reading you are getting on the GPR may not be. I would check the GPR with the GP's calling for power, the input and output should read almost the same. when the GP's are not calling for power the in put should have power and the putput should read 0. If you got the 12.5 in and 10.6 with the GP's calling for power I would replace the GPR. It sounds like it is starting to burn the contacts inside the GPR. If you got the 12.5 wile the GP's where not asking for power and then the 10.6 while they were. I would check the battery cables on both end and the grounds; you should have more power then 10.6 volts. I hope this helps

[JLElectric]

The gpr is sending power for atleast 2 min. Im gonna go ahead a change that out. I did remove one valve cover to look at the harness. It looked fine.

[dfdinc]

are the 12.5 and 10.6 volt readings both wile the GPR is sending power to the GP's

[JLElectric]

I changed out the gpr. I took both valve covers off. All my glow plugs are fine and the harness look good. It 30* outside this morning. I tried to start my truck and it won't. Turns over but the batteries about went dead. When I do turn my key on, when the glow plugs kick on my lights dim. Its almost like I am losing voltage somehwere. This new relay is doing the same thing. 12.5 amps then when I turn the glow plugs on it drops to 10.5. My batteries and batt cables are new

[JLElectric]

I see others have spent a lot of money trying to fix this. I have done the injector buzz test, its fine. Im going to double check the batteries and the cables. And starter cables and alternator cables. If my hpop is leaking into the valley would that have anything to do with it? I actually saw that a post. Im going to go ahead and change the orings on my fuel filter housing.

[JLElectric]

Fixed! Neative batt. cables had a couple splits with a little bit of corrosion. Had to look really good to find. I replaced them and now it starts like a champ.

[dfdinc]

Im glad you found it, some of the voltage drop problems are hard to find but with determenation you can save a lot of $$$$