BX glow plugs - current draw favor

[rusty1778]

Hello all, I'd like to ask a favor from the group. Anyone who has a BX and a DC clamp meter, can you hook it to the main wire connected to the glow plug bus bar and see what kind of draw you get when you activate the glow plugs? I get around 32 amps initial, but it drops to under 20 amps after 5 seconds. Not sure if that's a problem, it seems like it is being a bit hard to start in the cold weather this year for the first time ever.

Thanks in advance!

 

[number two]

Seems like glow plugs pull 10-12 amps each.
Good Luck!

 

[BravoXray]

The drop in current draw as they heat up is normal. As they heat up their resistance increases and the current drops.
Sounds like about the correct current draw though.

 

[Dave M7040]

Hello all, I'd like to ask a favor from the group. Anyone who has a BX and a DC clamp meter, can you hook it to the main wire connected to the glow plug bus bar and see what kind of draw you get when you activate the glow plugs? I get around 32 amps initial, but it drops to under 20 amps after 5 seconds. Not sure if that's a problem, it seems like it is being a bit hard to start in the cold weather this year for the first time ever.

Thanks in advance!

I suggest rather than focus on the current draw of all three GP's, you need to verify the correct function of each one.
Disconnect the lead between the three and then measure the resistance of individual ones to ground.

Have you installed a block heater as this can affect starting in unexpected ways.

Dave M7040

 

[rusty1778]

I suggest rather than focus on the current draw of all three GP's, you need to verify the correct function of each one.
Disconnect the lead between the three and then measure the resistance of individual ones to ground.

Have you installed a block heater as this can affect starting in unexpected ways.

Dave M7040

I'll try that, what's the go/no go for restance readings? It has a block heater, one with 'made in Canada' on the plug. The block will be over 50C in a couple of hours and it starts like summer. It's just never struggled to start down to -15 until this year even when it's not plugged in, so it made me suspect a bad plug.

 

[Dave M7040]

Here is the required GP reading from the WSM. 0.9 ohms

This next test is to verify the GP's are being powered both during PREHEAT and also START on the key switch.

I have not readup on how your GP's on time is controlled. If it is all manual then the block heater is no problem.

If there is a controller using the engine block temp to determine on time, the warm block results in a very short GP on time yet the engine is inhaling very cold outside air and can have big problems getting fired.

Since you are not currently concerned with using the block heater then focus on the condition of the GPs individually and also the key switch in two positions mentioned.

Tell me about your fuel supply. Do you have a bulk tank, do you buy and bring home in cans, if so where and when do you buy. I see many people buying and then trying to use fuel from warmer seasons in very cold weather perhaps by using some mechanic in can as an additive.


Dave M7040

 

[rusty1778]

Thanks for this info Dave, much appreciated. I'll give this a try when I get some time after work some evening. I believe the BX is fully manual on the GP, the key is spring loaded in the GP position and when you release it the current disappears. I'll test the leads in the start position while I have it disconnected.

Fuel supply is 2 plastic 20L jerry cans. Homeowner with no other diesel equipment. Guaranteed some of it is still summer diesel, I don't think they switch to winter diesel here until the fall. I've had the pre lift pump filter freeze before, which is common on these since there is no separator. Since then, I've treated all the fuel with 'diesel-mate' and have had no issues since. It runs at full power/RPM with the snowblower no issues, so I don't suspect a fuel delivery problem. In fact, I went through a whole tank cleaning the yard after the most recent snowstorm.

 

[LittleBill21]

sounds like they work exactly like mine, 30 amps initially dropping around to 14.7 amps for the rest of the duration. i wondered why it dropped as well, but one of the above posters explained it. i just tested this last week on a 3 cyl mitsu engine (one in my signature)

ironically i checked for the same reason. then I added some new fuel, and it seems better now, after playing with the glow plug wiring as well

 

[rusty1778]

What I just refilled it with I know is winter diesel and I treated it as well, so I'll be interested to see if it starts easier.

 

[Norm W]

I always checked glow plugs individually with a test light made from an old head light. A broken element can sometimes make contact giving a false reading on a meter. The headlight draws enough current to break that false contact reading.