MEP003-A Manifold heater wiring Please Help.

[jlboyce]

Hello all. I am brand new to the Forum, and hail from the eastern slope of the rockies, near the Royal Gorge.
I have an MEP003-A that I just reconditioned the injectors in, and the machine was received with 3 broken glow plugs. I don't want to pull heads, so now need to get manifold heaters working. I am aware that this machine uses 2 12v heaters in series, and have researched all the posts I can find on here to try to determine the grounding scheme for the heaters. I find that the aluminum plate which the heaters are screwed into is totally electrically isolated from the intake manifold. In a post I found here, it is mentioned that a wire runs from one of the mounting plate bolts up to one of the manifold mounting bolts. I find no such wire nor any evidence of such wire on my machine. Will I fry the heaters if I remove the insulating sleeve and washer from one of the mounting plate bolts, to provide ground for the heaters? Anyone on here with experience with this circuit please advise me.
Thank you in advance for any help.

 

[jlboyce]

[h=2]MEP003-A Manifold heater wiring Please Help.[/h]

Hello all. I am brand new to the Forum, and hail from the eastern slope of the rockies, near the Royal Gorge.
I have an MEP003-A that I just reconditioned the injectors in, and the machine was received with 3 broken glow plugs. I don't want to pull heads, so now need to get manifold heaters working. I am aware that this machine uses 2 12v heaters in series, and have researched all the posts I can find on here to try to determine the grounding scheme for the heaters. I find that the aluminum plate which the heaters are screwed into is totally electrically isolated from the intake manifold. In a post I found here, it is mentioned that a wire runs from one of the mounting plate bolts up to one of the manifold mounting bolts. I find no such wire nor any evidence of such wire on my machine. Will I fry the heaters if I remove the insulating sleeve and washer from one of the mounting plate bolts, to provide ground for the heaters? Anyone on here with experience with this circuit please advise me.
Thank you in advance for any help
​

 

[justacitizen]

i am pretty sure mine has the ground wire from bolt to the mounting screw on plate. better wait until someone else chimes in just for sure though. one thing i do know from experience is that to start reliably in cold you will need the glow plugs also.

 

[Triple Jim]

The schematic shows 24v power going to one plug, then to the other, then to ground. If they're mounted to an isolated plate, I'd expect the power goes to the top of one, then out of it into the plate, then from the plate into the second heater (backwards compared to the first heater), then out the top of it to ground. If you ground the plate, you'll put 24v on the first heater, and that would be bad.

I'll try to watch this thread, and if you still have a question tomorrow, I can go look at mine to confirm.

 

[jlboyce]

The 24v circuit hits the first heater at the top of the heater, then has a short jumper to the top of the second heater. Both heaters ground to the plate through their threads. My machine had no ground wire attached. I have determined from researching old posts here, that factory wiring included a jumper from one of the plate attachment bolts to one of the bolts which hold the intake manifold to the heads. Since 24 volts is wired to the heaters in series, I'm wondering if the factory ground wire is stainless steel stranded 12AWG wire to add resistance, or just copper to take the grounding point directly to the engine assembly instead of depending on the intake manifold. Thank You Triple Jim for your interest and help. If your machine has the jumper I describe, could you see if it is copper or some type of resistance wire? Thanks again.

 

[Guyfang]

If you look in the -34 manual, it describes how to make each and every wire in the wire harnes. It tells you what kind of wire to use and how long to cut and what ends to put on it. When I get home and you still need the info, I will look in the manual.

 

[Triple Jim]

I looked at mine. It's wired exactly as I thought. 24v comes in to the top of one, and a short ground wire goes from the top of the other to a bolt on the engine. The mounting plate connected the two together, and is not grounded.

To wire it as you said would put 24v one each one, in parallel, so either the heaters would have to made to operate on 24v, or they're miswired and already blown. I'm absolutely sure that no resistance wire was used.

I agree with justacitizen that the glow plugs are more important in getting the engine started than the intake heaters. The indirect injection design is not good at starting without the glow plugs.

 

[Chainbreaker]

...I agree with justacitizen that the glow plugs are more important in getting the engine started than the intake heaters. The indirect injection design is not good at starting without the glow plugs.

Yeah, about the only way to start it without working glow plugs would be to somehow bring the unit (oil, cylinders, etc.) and ambient air up to about 60F so engine compression would be enough to fire it off. About the only way to do that, short of a heated shop/garage would be to use an oil pan heater and warm the air surrounding it (tarp over it & heat gun or hair dryers blowing hot air?). Of course during a power outage your not going to have electricity to do that. If you do some searches here on SS there are some threads about removing broken glow plugs. Worst case you can remove the heads and take them to a machine shop to have them removed. Then when replacing with new glow plugs be sure to use the proper size copper washers and anti-seize. I use the copper anti seize.

 

[jlboyce]

Many thanks to Triple Jim and vielen dank to Guyfang. I will wire in series as Triple Jim suggests. Heaters were miswired when received, but with no ground provided, did not cook the elements. I realize that glow plugs are necessary with pre-chamber engines, but with heads in present condition do not have the wherewithal to pull and recondition. Hoping that with operational heaters and plumbers torch in air cleaner housing will get acceptable

 

[jlboyce]

Sorry, my last post didn't show up completely. Hope to be able to start using heated intake air, we'll see. Thanks to all for your interest and help.

 

[Guyfang]

Yeah, about the only way to start it without working glow plugs would be to somehow bring the unit (oil, cylinders, etc.) and ambient air up to about 60F so engine compression would be enough to fire it off. About the only way to do that, short of a heated shop/garage would be to use an oil pan heater and warm the air surrounding it (tarp over it & heat gun or hair dryers blowing hot air?). Of course during a power outage your not going to have electricity to do that. If you do some searches here on SS there are some threads about removing broken glow plugs. Worst case you can remove the heads and take them to a machine shop to have them removed. Then when replacing with new glow plugs be sure to use the proper size copper washers and anti-seize. I use the copper anti seize.

If if push come to shove, use the fire stick. I take the air filter out. Then take a nice long, thin rod, a gas welding rod is just the thing. We took a piece of cloth, jeans being a good material. Fold a small loop in the end of the rod, and pinch it closed around the cloth. Then dip the cloth in the fuel tank. Let it drip mostly off. Light it on fire, and hold it in front of the open air cleaner canister. Start the engine. The heated air is sucked into the intake, and the engine starts "right now". Works every time. The fire stick was the accepted way to start the old Herman Nelson heater, without loosing all the hair off your hand, arm and sometimes your head.

 

[justacitizen]

for a cheap alternative you could install a thermostart https://www.asap-supplies.com/us/thermostart-bonfire-heater-plug-for-perkins-4108

i have some on tractors and other machines and they work flawless.

 

[jlboyce]

Thanks to all of you for your help and advice. Today it was 55F here. I wired the manifold heaters properly per Triple Jim's advice, tested them for operation, and the machine fired with some smoke, but very little rough running after 30 seconds of manifold heaters and 5 seconds of cranking. The injectors have new nozzles, and are calibrated evenly for 1950 PSI break point. When the temperature gets below 40F I will use 1 minute of manifold heaters and plumbers torch in air cleaner canister. Thanks again to you all.