hard start problem

[pdub58]

I am puzzzled. I live in Michigans Upper Peninsula where the winter has been very cold this year, but I have been able to start my M1008, no problem, without plugging in the block heater as long as the temps dont drop below 5 degrees. As the temps have been rising more frequently into the 20s by day and single digits at night lately it has been taking much more cranking to get the truck started. Last week on our warmest day in 4 months (40 degrees) i couldn't start it at all. I have tried several times in the last few days while the temps have been in the 20s and 30s to no avail. Today I decided to plug it in for a few hours and try it (it was 30 degrees all night and 40 during the day today). It started instantly. hmmm?
Here are the facts about my truck: I have had a fuel leak from the throttle shaft since I bought the truck almost a year ago, but it hasn't kept the truck from starting quickly. I have done the spin on fuel filter mod. I have rebuilt the starter and it has worked quick and flawlessly for 6 months now. I have combed through many posts on here and cant find anything quite like my problem.

Any ideas?

 

[Warthog]

Make sure your glow plugs are operational. With it starting when the warmer was plugged in leads to the GPs not working. They don't last forever.

If they are bad many go with the AC-60s and remove the 24v GP resistor pack and make the plugs a straight 12v

 

[Westech]

A side note on removing the resistor:
The glow plugs can draw a ton of starting power off that first battery. The way the charging system works you are able to install a larger reserve capacity battery up front to insure the voltage won't drop too much while the glow plugs are heating up.
You do not need to match the batteries. Get a good one for the back and a honker for the front. It really does help and I cheaper.

 

[Keith_J]

Yes, that was the design philosophy for the ballast resistor (firewall mounted resistor coils), keep battery balance. Also remember, the starter solenoid (Doghead or stock) runs off 12 volts, the front battery. If voltage in the front battery is depressed from glow plug draw, this solenoid may not have the ability to remain closed. The Doghead replacement requires 6-8 volts to remain closed, the starter can depress voltage enough to cause it to open. Then you get a staccato sounding starter engagement, definitely hard on all stater components.

 

[pdub58]

I should have noted that this is a truck that has been converted to 12 volts before I bought it. I read about the rosscommon meathod and it seems to be consistent with that. This being said, I checked the resistance in my glow plugs and none of them have continuity at all. They are AC60G and were new about 6 months ago. My GP relay seems to be working correctly, I have 12v to the red wire on top, 12v to the orange when the key is on and 12v to the pink wire while the wait light is on and the relay is pulled in. What may have caused all of my glow plugs to go at once like this? Is it possible the relay stuck once before burning up the plugs but works fine now?

 

[Warthog]

Your GP relay is on all time time. It has burned out your glowplugs.

 

[pdub58]

What was the indicator to you that it's on all the time?

 

[Warthog]

Your description of 12v on the orange wires. It should only read voltage when the GP controller card calls for it.

The big red wire will be hot at all times. The pink wire will be hot whenever the key is on. The light blue wire is a ground for the GP relay and it will close when the controller says to. The will energize the internal coil, close the main relay and send 12v to the orange wires which go to the GPs.

The GP relay must have an isolated ground (not use the mounting bracket for ground).

 

[pdub58]

I just tested again to be sure I was correct and I was mistaken. The orange wire on the bottom reads 12v when the relay closes and goes to 0 volts when the relay opens. The pink wire has 12v when relay is closed and 0 v when relay opens. The blue wire has 0 v when relay is closed and 12v when it opens. Does this seem correct?

 

[pdub58]

This is what I am looking at

 

[Warthog]

That is the correct operation. Maybe you got a bad batch of glow plugs.

You might edit your profile and add to you sig line that your truck is converted to 12v.

 

[pdub58]

I changed all the glow plugs and it fires right up. Thanks for your help Warthog.

 

[Keith_J]

Relays stick. It would only take one stick to burn all glow plugs out.

 

[doghead]

Relays stick

In this application that would not be likely. More likely for the control system to fail(on) than the relay to "mechanically" stick on.


I'm curious where the 12v supply for the relay is coming from. It can't be seen in the pics

 

[pdub58]

I'm curious where the 12v supply for the relay is coming from. It can't be seen in the pics[/QUOTE]

It's being fed from the buss bar on the firewall, behind the battery

 

[doghead]

So, the resistors on the firewall were removed as well?

 

[pdub58]

Yes

 

[pdub58]

.

 

[pdub58]

[quote

 

[pdub58]

In this application that would not be likely. More likely for the control system to fail(on)

Well.. My glow plugs were all changed about 3 weeks ago and several have burned out already. Could I assume my controller card is acting up?