3016/3616 Hard starting/ glow plugs failing.

[rdinatal]

BillC72,

What's are those diodes rated at (amps)?

-R

 

[BillC72]

6 amps

 

[ronchp]

Great information! I'll check it out this weekend.

 

[jgedmond]

The controller is mounted on the firewall with one 10mm bolt. You will want to remove the coolant tank and set it aside. There are two connectors on the controller. the one on the left is where you will find the white/orange wire. You want to install diode such that power can come from the controller. If you purchase the same diode I used....one side has two black leads, cap and stow one of them, cut the w/o wire, leaving plenty of room for a butt connector (slice the black covering to achieve this). Connect the other black diode lead to the w/o wire from the controller. Then connect the colored diode lead to the other side of the w/o wire. this will complete the fix. I am unsure of how long this diode should last, so I wired in my additional dash light so that I can SEE anytime the glow plugs are getting power. My dealer is in another state btw, and I did call to inquire about this issue before seeking help on this forum. The service tech I spoke with had never heard of this backfeeding issue and advised that my controller was probably bad. I'm merely guessing on this, But I presume there is a diode inside the NGK controller that fails, allowing the backfeed. I also presume that the diode I added is replacing that one inside? Not sure. I just know this works and it only cost me two set of glow plugs before I got the help I needed and like six bucks for the diode.

I just went thru this same issue. With the help of the OP I was able to correct this issue and added a second dash light to see future failures. I bought a blocking diode for use on vehicle trailer lights, wired it into the glow plug control box on the white/ orange wire. then added a light on the dash wired directly to the glow plug feed wire. Now I can see when the plugs are energized weather the gp light is on or not. My first set of plugs were fried because of the back feeding. The diode corrects that. And now when I turn the key on, the gp light illuminates as well as my added light. The factory light goes off and I start my 3616, then I see my added light flash four times over the next 30 seconds or so, then it stays off. If my diode was to fail, my added light will come on to tell me that the glow plugs are getting power. Not a very hard fix once you know which wire to use. Mahindra is really proud of the glow plugs, you don't want to keep buying these things.

BillC72 thanks for the very clear explanation which helped me greatly in doing this modification. I found that 12V was always going to the glow plugs and all 3 had high resistance. With 12V to the plugs, less than 1A was flowing through the circuit. New glow plugs are on order from sparkplugs.com for $13 each instead of Mahindra's $80!

I mounted a 12V yellow LED in the panel just below the factory glow light and wired it to the front glow plug and ground. I also found "solar cell" diodes rated at 10A / 1000V and wired one into the white / orange wire off of the NGK QGS controller. The light behaves just like BillC72 said. I read up on glow plug systems and I think the short powering of the glow plugs is to reduce emissions during cold running and is also controlled by the engine thermocouple.

Looking forward to years of "as new" cold start performance! :thumbsup:

 

[Roondogy]

I just went thru this same issue. With the help of the OP I was able to correct this issue and added a second dash light to see future failures. I bought a blocking diode for use on vehicle trailer lights, wired it into the glow plug control box on the white/ orange wire. then added a light on the dash wired directly to the glow plug feed wire. Now I can see when the plugs are energized weather the gp light is on or not. My first set of plugs were fried because of the back feeding. The diode corrects that. And now when I turn the key on, the gp light illuminates as well as my added light. The factory light goes off and I start my 3616, then I see my added light flash four times over the next 30 seconds or so, then it stays off. If my diode was to fail, my added light will come on to tell me that the glow plugs are getting power. Not a very hard fix once you know which wire to use. Mahindra is really proud of the glow plugs, you don't want to keep buying these things.

 

[Roondogy]

I'm unable to locate the orange/white wire coming out of the NGK QGS controller. On the left side looking at it from the front is a solid red wire and a black/red wire. Both pretty heavy gauge wire 10 ga. The right side looking from the front there is a white/red wire. Maybe 14 ga. wire. I'm not sure where to install the diode. My glow plugs are on all the time.

 

[5030]

My only comment is, glo plugs are for intermittent use only and all glo plug equipped engines are pre-chamber engines, designed with a smaller pre combustion chamber in the head that allows the glo plugs to heat the cold diesel fuel upon cold cranking to initiate the combustion process. That process then allows the main combustion chamber to ignite the diesel fuel and allow the engine to start and why it 'bangs and clangs' upon initial start up as the fuel in the main combustion chamber isn't igniting 100% and why you get a puff out the exhaust pipe. Glo plugs are for intermittent use only. If they are on all the time, they are most likely shot and need replaced. My Kubota's have a glo plug override under the dash panel that will limit the plug actuation to a pre set time. I can initiate the glo plugs via a starting key detent but if for some reason I hold the key in the glo plug on position for too long, the under the dash panel override will engage and turn them off.

Even in the dead of winter up here, with a fully charged battery, I never need longer than 15 seconds of glo plug actuation to start my diesels.

If I were you. I'd install an external toggle switch to activate the glo plugs independent of whatever starting system you have and be able to turn them off as continuous operation will destroy them pretty quickly. Like I said, they are for intermittent cold start use only.

Candidly, I've never replaced a glo plug in any of my diesel pre chamber engines, including my '97 7.3 Navistar diesel pickup truck.

One other thing to note is, your starting battery as well as all the physical connections, must be clean and corrosion free and the battery must be fully charged, especially in cold weather. Cold temps adversely impact a starting battery's ability to provide sufficient starting amperage to turn over a cold engine with thickened lube oil and the extra amp draw on the glo plugs even compromises the starting battery's ability to provide sufficient amperage.

Batteries and corroded connections are the most overlooked items on any diesel engine. I replace the starting batteries and brighten all the connections and apply di-electric grease to them, every 5 years, maximum or load test the batteries to determine if I need to replace them sooner.

 

[Roondogy]

My only comment is, glo plugs are for intermittent use only and all glo plug equipped engines are pre-chamber engines, designed with a smaller pre combustion chamber in the head that allows the glo plugs to heat the cold diesel fuel upon cold cranking to initiate the combustion process. That process then allows the main combustion chamber to ignite the diesel fuel and allow the engine to start and why it 'bangs and clangs' upon initial start up as the fuel in the main combustion chamber isn't igniting 100% and why you get a puff out the exhaust pipe. Glo plugs are for intermittent use only. If they are on all the time, they are most likely shot and need replaced. My Kubota's have a glo plug override under the dash panel that will limit the plug actuation to a pre set time. I can initiate the glo plugs via a starting key detent but if for some reason I hold the key in the glo plug on position for too long, the under the dash panel override will engage and turn them off.

Even in the dead of winter up here, with a fully charged battery, I never need longer than 15 seconds of glo plug actuation to start my diesels.

If I were you. I'd install an external toggle switch to activate the glo plugs independent of whatever starting system you have and be able to turn them off as continuous operation will destroy them pretty quickly. Like I said, they are for intermittent cold start use only.

Candidly, I've never replaced a glo plug in any of my diesel pre chamber engines, including my '97 7.3 Navistar diesel pickup truck.

One other thing to note is, your starting battery as well as all the physical connections, must be clean and corrosion free and the battery must be fully charged, especially in cold weather. Cold temps adversely impact a starting battery's ability to provide sufficient starting amperage to turn over a cold engine with thickened lube oil and the extra amp draw on the glo plugs even compromises the starting battery's ability to provide sufficient amperage.

Batteries and corroded connections are the most overlooked items on any diesel engine. I replace the starting batteries and brighten all the connections and apply di-electric grease to them, every 5 years, maximum or load test the batteries to determine if I need to replace them sooner.

 

[Roondogy]

Thank you for your quick response. I will do just that. I will install a separate switch.

 

[BlackOps]

ust cauht this thread. short story from a longer adventure - tractor was in shop for a leak and servicing. then they had troube starting - messed with it for over a month and then had too order glow plugs and now this AM found out they too had to replace the glow plug timer on a max 25. WTF is it with this timer thing going wrong on a number of tractors. took them a month to get glow plugs too. today is over 2 months now in shop.50 miles away!


Frustrated.

have a good one!