no start , i think some how i killed all the glow plugs and the resistor bank

[fastbuckink]

I parked one of my 1009s the other day and accidentally left an electric fuel line heater on overnight, so in the morning the batteries are dead. No big deal, i try to jump it with my other one. No go. Pull the batteries, charge them, still nothing. Crank and white smoke, i have fuel to the injectors. check the voltage at the glow plug solenoid. 24v. check the plugs. 24v. All the plugs are dead. waiting on a new set. pull the resistor bank. the tm says it should be .28 ohms, i get .5 so I have a used one of those coming. Hopefully that will fix it.

Any idea what caused this?. I is a daily driver, i parked it overnight and i was surprised that all this suff burnt out, by some how letting the batteries die or jumping it.

 

[cpf240]

No idea on what caused it. Perhaps now is a good time to remove the GP resistor bank and power the GP relay with 12v from the 12v buss right next to it.

 

[cucvrus]

What is an electric fuel line heater? And how is it powered?
Another question. How would the ballast resistors have anything to do with this type of failure?

 

[doghead]

Did you leave the key on for any length of time without the truck running?

 

[amphi]

And did you wait the required 3 to 5 minutes before attempting to start the truck?

TM -10 clearly states:

"Wait 3 to 5 minutes after hooking up slave cable to "dead" truck, before attempting to start it. Damage to the truck’s electrical system may result if the truck is started sooner."

"If one battery is missing, DO NOT attempt to slave start."

Example:
If the rear battery is completely shorted:
No voltage will be dropped resulting in the front battery and the entire 12v truck circuit seeing 24v. Not a good thing

Example:
If the rear battery is open or missing:
All voltage will be dropped and the front battery and 12v load will see nothing.

Anything in between these two extremes is possible with an imbalanced battery charge state .

This wait time is an attempt to allow the batteries to receive charging current form the source/slave and become somewhat balanced allowing the 12v circuit to see a voltage close to the designed 12 volts.

With the resistors bypassed it is possible to fry the glow plugs with over voltage during slave starting. Not sure how the GP controller would react to over voltage.

I think this might be why the resistors exists in the original design.

Your resistors might have been bypassed by the PO.

 

[cpf240]

...
With the resistors bypassed it is possible to fry the glow plugs with over voltage during slave starting. Not sure how the GP controller would react to over voltage.

Really? How? If the GP relay is getting its supply voltage from a 12v source, even if the NATO slave port is used, I don't see how they can get 'over voltage'... if that were the case, then the rest of the 12v system in the truck would be susceptible as well. In addition, the GP controller card is a 12v part. The sense wire is the only one that could ever see anything above 12v, if any of the GPs are bad, and it is designed for that purpose.

 

[flumsi]

Assumed that .5 ohm is measured correct, the over all current in the glow plug system during jump start was
I = U / R = 24V / (0.5 ohm resistor + 0.2 ohm all plugs) = 34 A
The resistor reduced the voltage by 34 A * 0.5 ohm = 17 V
The plugs saw the voltage 24 V - 17 V = 7 V
So: current and voltage were lower than usual and nothing should be damaged during jump start.

"With the resistors bypassed it is possible to fry the glow plugs with over voltage during slave starting."
Yes, if someone "bypasses" the resistor with a direct wire from 24V bus bar to glow plug relay (haha - "don't try this at home")

 

[MarcusOReallyus]

There's something weird here. If you see 24v at the plugs, they are all open. But how did they get that way? The higher resistance on the resister bank probably means one of them is open (there are two in parallel), which would cause LOWER voltage to the plugs, as already pointed out.

Somewhere in the process you fried your plugs, and possibly one of the resistors in the resistor bank. If it were not for the high resistor value, I'd say this is a classic cascade failure.

Maybe doghead's question points in the right direction. Or is the GP card inop, and keeping the GPs energized?

But what burned out the resister? Maybe the same problem. If it failed somewhere during the cascade event, there could still be enough jolts to fry the remaining GPs.

In any case, this would be a great time to lose those resistors. Unless you are slaving off of other 24v vehicles, they are a liability.

 

[amphi]

Really? How? If the GP relay is getting its supply voltage from a 12v source, even if the NATO slave port is used, I don't see how they can get 'over voltage'... if that were the case, then the rest of the 12v system in the truck would be susceptible as well. In addition, the GP controller card is a 12v part. The sense wire is the only one that could ever see anything above 12v, if any of the GPs are bad, and it is designed for that purpose.

See the first example in post #5 above.

 

[fastbuckink]

Ok guys, just to clear some things up. The inline electric fuel heater is a 12v, thermostatically switched. i have it wired to a switch and relay off of the 12v bus so it doesn't kill the batteries on a cold night. this is what i forgot to shut off and it killed the batteries. The first battery might have been stone dead because of this. I did wait a bit tho before i tried to start it. Nothing has been bypassed or hacked to 12 v as i know that may happen to these trucks. before it checked the plugs and resistor for resistance as stated in the TM's i checked the voltage at the noid coming off the resistor bank i got 24v. I pulled a gp wire and checked the voltage and got 24v. Which i figured was not what it should be. Then i checked the resistance of 6 of the plugs and got nothing, so i figured they are burned. After per the TM i removed resistor pack and checked the resistance and got .5 ohms. now my meter only goes to .1 so that might not be totally accurate but i was expecting .3 as per the .28 stated in the tm. if the resistors were "blown" i would think id get an open circuit as i did with the plugs.

thanks for the theories so for.

 

[MarcusOReallyus]

After per the TM i removed resistor pack and checked the resistance and got .5 ohms. now my meter only goes to .1 so that might not be totally accurate but i was expecting .3 as per the .28 stated in the tm. if the resistors were "blown" i would think id get an open circuit as i did with the plugs.

The resistor pack has TWO resistors, which are in parallel. Each resistor is .56 ohms. In parallel, that's .28 for the pack.

So, the fact that you got .5 says that one of the resistors is open, leaving you with the other resistor only, which on your meter probably measures .5. (And I'm not sure what the tolerances are on these, anyway. It's probably not very precise.)

Pull the resistors out of the pack and I'm pretty sure you'll measure .5 on one of them, and open on the other.

 

[fastbuckink]

ill check them tomorrow, its been a while since an electronics class, aren't most resistors like 10-20% tolerance? thought it was strange that the tm was so exact with what the ohms should be

 

[fastbuckink]

update

The resistors i ordered came in check the resistance and got .5 ohms. cleaned up the ring terminals on both the original ones and the replacement and checked it again. Got .5 ohms on both so i put the first one in. Just got done changing the glow plugs, which wasn't so much fun, on the street, in the setting sun, in the 30's. The puddle next to my tire was icing over by the time i was done. It started on the second crank.

 

[MarcusOReallyus]

When you say you got .5 ohms, was that for each individual resistor, or for the resistor pack? The pack should be .28 ohms (TM9-2320-289-20, page 2-65.0). Each individual resistor should be .56 (to be precise).

 

[fastbuckink]

The resistor pack, on both packs i got the same reading, hooking the leads up to the wires.

 

[fastbuckink]

like this

 

[MarcusOReallyus]

Gotcha.

That's not what the TM calls out. It says the resistance should be be .28 for the pack, so I think each of your packs may have one of its resistors open. Each individual resistor should be twice the resistance of the pack, since they are in parallel.

Think of it this way - when resistors are in parallel, the current has more than one path it can take. Since it has more than one path, the total resistance is LESS than if it had only one path. Take away that extra path, and the total resistance will increase.

In this case, since there are only two equal resistors, the total resistance is just half the value of one resistor.

Running with the pack resistance high will cut the voltage to your glow plugs. That's not going to hurt them at all, but they might not get hot enough for reliable starting in all conditions.

 

[fastbuckink]

Ill check the pack in my other 1009 tomorrow when the weather clears. Does anybody have a source for these? Anybody feel like checking theirs and see what they get?

 

[MarcusOReallyus]

Well, I just measured mine, and it's .5, too. That's probably why I've been having trouble starting, or part of the reason. I have GPs on order, so I expect to see what kind of shape mine are in maybe this Saturday.

I'm not surprised my resistor bank is just a bit out of spec. The wonder is that it was working AT ALL! Take a look:




I don't know if that's genuine Iraq mud or what, but it's tough stuff. VERY hard to remove.

I'm not going to bother with cleaning up the resistors, because they are now out and staying out, but one of my alternators was full of it, too. I'm going to start a thread on that interesting saga once I get it wrapped up.

 

[fastbuckink]

if my third one rings out at .5 i have a hard time believing all 4 are bad. maybe the tm is wrong or .5 is within tolerance.