cucv glow plug controler and 12v conversion

[richingalveston]

I have a M1009 and i am considering the 12V conversion.
the reason for the conversion is because i plan to add a much larger 12v load
in lights stereo and other accessories wich will cause exceptional heat from the resistor. and it is not the best 12V source, because the resistor nocks the voltage down closer to 10.5 or 11 volts and most new 12V items are good at 12V or a little higher and not lower. (correct me if i am wrong)

upon further study it appears the only thing converting to 12v you cannot change or correct is the glow plug relay controler card. reading the glow plug sequence opperation posted when you perform the 12V conversion, the glow plug controler will always be in the safety mode of operation because it will now normally be reading the Voltage source between 12.5 and 13.6 when on battery. Thus it will never cycle the plugs properly and stay in safe mode of turning them on and off.

if all of the above is correct then i was wondering if anyone tried to install a small 1 to 2 volt drop resistor directly in-line on the power input to the control board and if this would allow the CUCV glow plug controler to operate normally.

i have the 12v starter and plan to change glow plugs before i start driving it (currently being painted, see M1009 repaint project)
so i would like to know all my options.

if my assumptions are wrong above please let me know.

 

[doghead]

Your confused. The only thing the resistors on the firewall are used for, is the glow plugs.

Your starter is 24 volts.

Everything else is 12 volts and runs solely on the front battery(charged by the DS alt).


Changing the supply voltage for the Glow Plugs, to 12 v, does not adversely affect the GP controller card. The advantage/reason to resupply the GP relay with 12 volts is to avoid all of the glow plugs going bad, when only one is bad. That's it.

 

[rnd-motorsports]

As doghead stated the resistor only controles the glow plugs and just the glow plug relay under the hood the other itams in the cab are still only 12 volts! the only true 24 volt itam on the truck is the starter and the jump slave in the grill. Everything else is still just 12 volt. I use mine as a daily driver and work truck so I convert mine to all 12 volt for that reason do not need to jump a tank or whatever and if I need a jump or need to give a jump I can and less parts to go bad and if they do I can go to any parts store and get parts you cant get a isolated ground alt or 24 volt starter anyplace! some guys here dont like to change them but its not a big deal its still the same truck just less parts to go bad and less hasles to get fixed!!

 

[davidkroberts]

actually with dual 100 amp altenators I dont see what you are going to gain by converting to 12v. Just run whatever extra your going to run off the front battery. The DS alt charges the front 12v side battery. The battery charging system doesnt become 24v until the post closest to the firewall. As far as jumping a vehicle off just use the front battery. I can jump off anything with mine civilian or military. You can even be jumped off with the front battery using a civilian vehicle if the rear battery isnt completely dead.

I would be scared to change to 12v on a CUCV. These trucks are fairly complicated and most problems with them have been identified and fixed on list if you stay with the stock system. If you convert it nobody is going to be able to tell you for certain what is happening because you will be changing the wiring schematic.

As to a starter you can still run a 12v starter you just have to move the hotwire from the 24v busbar on the firewall to the positive post on the front battery. Its a one wire conversion but a 24v starting system is much stronger.

 

[markg]

thanks, mark

 

[rnd-motorsports]

When you convert to 12 volt then anybody can work on it! its not complicated its complicated becouse of the 24 volt and daul alts thats why nobody will work on them you take that away and they are just a 85 chevy 1 ton truck thats it alot easyer to work on. the millitary spec. made them so most places wont work on them becouse of the 24 volt starter and daul alts thats it nothing else is differant sorry you are not going to prove anything being simpler bye staying with 24 volts and two alts most dont know about it and see it and gets scared off its a simple system and is not needed for a everyday driver that will never jump start a tanks or whatever alot less costly to replace parts and less parts to replace when you remove the 24 volt starter and one alt! and after doing so like I stated anybody will work on it being its just a 80s chevy truck!!!!!!!!!!!!

 

[ranchhopper]

Its relatively easy to convert to 12 volt I have done a few there is a step by step write up with pictures done by rosecommon I think I found it on this site in the resources section but you will have to change your starter to a 12 volt unit and they are pricey.

 

[richingalveston]

thanks for the input, i already have the 12v gear reduction starter which i beleive ran around $400 when i bought it 4 years ago for my first M1009 which is now the parts m1009 due to floor and body rot. it is barely used since i only drove the truck a dozen times a year for dear hunting.

For the new m1009 i plan to change the glow plugs before i start driving it. and it already has the upgraded glow plug relay (not sure which one but it is the round one not the stock)
My NAPA dealer did not have the "doghead" relay in stock but should have it after lunch tomorrow. i plan to do this right away.
still to do: is the resistor bypass and maybe (probably) 12V conversion

am i missing any upgrades that should be done before i make it a semi-regular driver.

thanks for the input
Rich

 

[SouthernSteel]

Well i personaly like the 24 volts as i have figured out a way to regulate the voltage for use with cb equipment that was my whole intentions of buying the m1008 i love my truck the 24 volts is defintely a better way to turn the massive 21:1 Compression diesel that is in the cucvs also our local lawenforcement have got cucvs and old military humvee which are all 24 volts still so that is why i left mine 24 volts i have had some hiccups but for the most part nothing serious so far i did the dog head relay and havent had any problems since but its your truck do what ever u want im pleased with my truck the way the military made it

 

[richingalveston]

doghead realay and 12v

i have heard some people say the doghead relay is not nec. when going to twelve volt.
i have already bought it and planned on doing it along with 12V conversion.

I would think it would the relay would be required with 12v change since lower voltage means higher amperage on the relay.

rich

 

[D T]

southernsteel,you got me soo curious,what do you have ,a sweet sixteen?,what kind of potentiometer are you talking about?....if you dont mind,thanks

 

[rnbebout]

Hello. I Have an 85 military blazer that I can't seem to get enough power to the glow plugs. It's already been changed to 12v system. I'm getting 12+ to in put side of glow plug solenoid, just can't get enough on out put side. What do I need to do? Any help would be appreciated.

 

[doghead]

Is the resistor bank on the firewall connected? If so, remove it,

How much is coming out when the relay is closed(GPs on)?

 

[rnbebout]

Hello. I have an 85 army blazer that I can't seem to get enough power to the glow plugs. I have tried 2 different glow plug solenoids, with no luck. It has been changed to 12v, so I'm wondering if that has any thing to do with it! I'm getting 12v+ to input side of glow plug solenoid but not on out put side. Any help would be appreciated.

 

[doghead]

Yeah, we know this already!

 

[rnbebout]

Low volts to glow plugs..

Yeah, we know this already!

Sorry, didn't realize it posted twice! Any Ideas I could try?

 

[cpf240]

Step one: take/provide the voltage measurements as per the troubleshooting section of the TMs
Step two: post the results here along with details as to how your setup is wired

 

[rnbebout]

Low power to glow plugs

Step one: take/provide the voltage measurements as per the troubleshooting section of the TMs
Step two: post the results here along with details as to how your setup is wired

Well, right now I can tell you that the glow plug out put side is 2 orange heavy gauge wires,one to each side of engine. Factory spliced to the green glow plug wires. Tested input side voltage with battery tester. But friends tester broke before testing out put side. Using test light, it lights up bright on input side but not near as bright on output side. And when using test light on the 2 small terminals on solenoid, terminal marked (s) lights test light and terminal marked (i) lights test light. Should one of these terminals be grounding? Thanks for the help!

 

[cpf240]

Well, right now I can tell you that the glow plug out put side is 2 orange heavy gauge wires,one to each side of engine. Factory spliced to the green glow plug wires. Tested input side voltage with battery tester. But friends tester broke before testing out put side. Using test light, it lights up bright on input side but not near as bright on output side. And when using test light on the 2 small terminals on solenoid, terminal marked (s) lights test light and terminal marked (i) lights test light. Should one of these terminals be grounding? Thanks for the help!

From this description, it *sounds* like the relay is probably bad, as well as being the wrong one for the stock CUCV GP system. What you have there sounds like what is commonly called a "starter" solenoid. The CUCV GP relay *must* be an isolated-ground unit, otherwise it might be on all the time and could case issues with the alternators. The stock GP controller switches the ground connection "on" and "off" to operate the solenoid.

Please read the FAQ/Stickies section of the CUCV section of the forum, where you will find suggested part numbers for the correct relay. I'm also guessing that the contacts inside your relay/solenoid are carboned up, thus not passing enough current to the GPs.

 

[rnbebout]

Low power to glow plugs

From this description, it *sounds* like the relay is probably bad, as well as being the wrong one for the stock CUCV GP system. What you have there sounds like what is commonly called a "starter" solenoid. The CUCV GP relay *must* be an isolated-ground unit, otherwise it might be on all the time and could case issues with the alternators. The stock GP controller switches the ground connection "on" and "off" to operate the solenoid.

Please read the FAQ/Stickies section of the CUCV section of the forum, where you will find suggested part numbers for the correct relay. I'm also guessing that the contacts inside your relay/solenoid are carboned up, thus not passing enough current to the GPs.

I can add that each time I tried a new GP relay, It had to be special ordered, ie; listed as GP relay only!