12V glow plug wiring question..

[atsah]

No grounding problem, I just ohmed out from the ground on the plugs to the chassis.

 

[atsah]

I'd pull the plug on the ignition switch, and check for corroded connections first!. then I'd check each glow plug with an ohmmeter for continuity, and replace any that are bad. getting the wiring diagram is a must have, you don't want to either spend too much time on this repair, OR damage your glow plugs..

I pulled the plug and all is good.

Normally this tractor would take several tries before starting cold, I just went out and gave it glow for 20 seconds and put the throttle up to 1/2 way and turned it while moving the throttle down slowly and it started right up..

What do you guys make of that???

 

[radios1]

I pulled the plug and all is good.

Normally this tractor would take several tries before starting cold, I just went out and gave it glow for 20 seconds and put the throttle up to 1/2 way and turned it while moving the throttle down slowly and it started right up..

What do you guys make of that???

it seems unplugging and re-plugging the switch did that.. no?

 

[atsah]

it seems unplugging and re-plugging the switch did that.. no?

No I tried the throttle thing before I messed with the switch..

 

[Industrial Toys]

Seems a bit strange to me that a high current circuit like that would be intermittent, unless the contacts are burned.

 

[atsah]

Seems a bit strange to me that a high current circuit like that would be intermittent, unless the contacts are burned.

Either this tractor needs throttle to start or there is something inside the ignition switch because from what I can tell there is nothing wrong in the glow plug circuit.

I'm going to wait a little while and try giving it throttle again while cranking to see if it starts like it should..

 

[atsah]

If the tractor starts without an issue a few more times, I am thinking maybe it's more of a fuel problem considering that giving it more fuel at first start makes it start right up. When you give it throttle, what is actually happening?

 

[Industrial Toys]

This isn't a very helpful statement, but a friend had a few Bolens and I often witnessed very hard starting attempts. I always thought on account of they were old, worn out and probably had poor compression. Even when having been just used, they were hard to restart.

 

[atsah]

I tried it again without throttle 40 minutes ago and it was hard to start. I just tried it again with throttle and it started right up.. Crazy..

 

[radios1]

I tried it again without throttle 40 minutes ago and it was hard to start. I just tried it again with throttle and it started right up.. Crazy..

it's a fuel problem then.. I wonder if the injector pump is connected to the throttle?.. if not, then it's a fuel/air mixture problem.. maybe too much fuel, and not enough air, since opening the throttle lets more air in..

 

[atsah]

it's a fuel problem then.. I wonder if the injector pump is connected to the throttle?.. if not, then it's a fuel/air mixture problem.. maybe too much fuel, and not enough air, since opening the throttle lets more air in..

The throttle is connected to a unit that connects to the injection pump. I would assume the unit has timing gears and such inside of it..

If that's the case and it doesn't have enough air, what would cause that?

 

[flyerdan]

It could be that your throttle is out of adjustment and closing too far; after it has ran for a while and you close the throttle all the way, does it die, or slow to faltering? My dad had an ancient ('38 or '39) D4 cat that you shut down with the throttle.

 

[atsah]

It could be that your throttle is out of adjustment and closing too far; after it has ran for a while and you close the throttle all the way, does it die, or slow to faltering? My dad had an ancient ('38 or '39) D4 cat that you shut down with the throttle.

No problem with that, turn it down to idle and it idles..

 

[thepumpguysc]

The amp draw is why people went w/ the Ford starter relay/solenoid.

 

[PILOON]

Bingo..

I have a test light and a DVM. I removed the plugs and ohmed them out, .07ohms on each one, so I think they are good. There is a light on the dash but no relay at all in the circuit. The plugs are connected with a buss bar, the power wire comes from the ignition with a tap to the dash light on a 5 amp fuse straight to the furthest glow plug. I get about 9V at the glow plugs but not all the time. The glow plugs look new and heat up fast if I put 12V to them and take it away quickly so they are good.

Sounds to me like the ignition switch is the faulty link.
Yes U could power direct to the glow plug 'buss bar' but with a heavy duty switch as the amps will be considerable.
But first I'd squirt some WD40 into the key switch slot so as to soften (disolve) the lubricant that was factory installed as that is a fairly common problem.
The grease they use cakes up and hardens making for poor contact especially at the higher amps the plugs draw.

If U do bypass with a manual switch use a spring loaded momentary type double pole toggle and use both sides in parallel to give U a 20 amp capability as plugs draw a fair bit of current. (most switches are rated at 10 amps)

When manually activating glow plugs do so for about 8 seconds or so at a time otherwise U might toast them.

U get 9 volts because of the plugs draw a lot and create a voltage drop plus that battery is weak.

 

[atsah]

Went out last night after it sat for 7 hours, gave it plenty of glow plug time 20 seconds. It turned over a lot before starting.

This morning I went out 26F and gave it 3/4 throttle and 20 seconds of glow plug time, it fired quickly and when it did I brought the throttle back to idle. If I remember right we had a Perkins a few years ago that needed throttle to start.

What is giving it throttle on first start actually doing?? Giving it more air or fuel or both??

 

[LouNY]

It's allowing the pump to push more fuel to the injectors.
Many engines will start better with a quarter throttle, some like more especially when cold.

 

[atsah]

It's allowing the pump to push more fuel to the injectors.
Many engines will start better with a quarter throttle, some like more especially when cold.

Maybe it's an indication of the injectors leaking the fuel back or down into the cylinders and it needs the throttle to fill the high pressure lines back up?

 

[atsah]

Just talked to a guy at a local injection place, he said he doesn't think the injectors are the issue, If they are leaking it would be hard to start hot as well which it isn't, he said some machines like throttle when cold and if it starts well with the method of cranking with the throttle 3/4 open and then backing it down to idle as soon as it fires then so be it..

He said half of the heavy equipment he works on require some throttle to get them to start quickly after sitting..

So I guess I just happened to stumble on the ingredients to start this particular engine quickly..