Another yard start

[Indyharleyguy]

Hey All, I think my hard start might be a little different?
When I try to start in temps even in the 70's it cranks fine but doesn't fire. Bus if I squirt just a tiny bit of ether it fires right away. They starts almost immediately after that. Both batteries and the starter are brand new. I have not replaced the glow plugs yet but since this is happening in warmer weather do you even need them? They do have a manual push button and they are getting 24 volts to them.
Any thoughts ?

 

[Barrman]

The glow plugs are needed anytime the inside of the cylinder is less than 159° according to a really long and boring paper Bosch published years ago. So, check your glow plugs and replace them if needed.

Here is a video of how to test them if you want to do that:

 

[ezgn]

The glow plugs are needed anytime the inside of the cylinder is less than 159° according to a really long and boring paper Bosch published years ago. So, check your glow plugs and replace them if needed.

Here is a video of how to test them if you want to do that:

I am going to say this believing that you already know, since you said a small amount of ether. Not a good solution to your starting problem. My guess is that your getting air into your fuel system. Check for rotted fuel lines and any place fuel might be leaking. Get a flashlight and go over every source of fuel components. You might be able to smell leaking diesel. Glow plugs should only be getting 12 volts. Sorry for posting on the wrong reply.

 

[Mullaney]

I am going to say this believing that you already know, since you said a small amount of ether. Not a good solution to your starting problem. My guess is that your getting air into your fuel system. Check for rotted fuel lines and any place fuel might be leaking. Get a flashlight and go over every source of fuel components. You might be able to smell leaking diesel. Glow plugs should only be getting 12 volts. Sorry for posting on the wrong reply.

.
Okay... So, I don't know how to fix your problem but by accident I solved my starting problem on my Cat 3116. Do nothing except turn on Main Power, then Press the red button to engage the starter. BY DEFAULT, the starter would grind for 30 or 45 seconds. To the point that I felt like I needed to release the red button, let it rest for a few minutes, then press again and in 15 seconds or so, truck fires right off.

Like I said, BY ACCIDENT my big fat foot mashed the accelerator peddle as I shuffled into a more comfortable position. Truck fired right off. It has NEVER ever cranked that fast since I got it...

You might try it on your HMMWV

Might be neat if somebody has a suggestion to solve that situation with my 3116.

 

[Tow4]

My truck needs the glow plugs to cycle three times no matter what. I can crank longer and get it to start, but I like it to fire right off. Waiting the extra 10 or 15 seconds is not a problem for me.

If the glow plugs aren't working, you need to find out why.

 

[ssdvc]

Sounds like a pin hole leak somewhere, even may be in the return line. Either that, or it could be your IP.

 

[Indyharleyguy]

The glow plugs are needed anytime the inside of the cylinder is less than 159° according to a really long and boring paper Bosch published years ago. So, check your glow plugs and replace them if needed.

Here is a video of how to test them if you want to do that:

Thanks I have some I can replace them with. If I measure right on the glow plug I thought I was getting 24 volts there and that meant they worked? Is that correct?

 

[ezgn]

Thanks I have some I can replace them with. If I measure right on the glow plug I thought I was getting 24 volts there and that meant they worked? Is that correct?

Glow plugs should be 12 volts. I would pull them out and make sure they are not swollen and bench test them like in the video above. Should be a fairly quick and easy task.

 

[Barrman]

A CUCV should have 12 volts at the glow plug. If you have 24 volts then something is wrong. Do you have the firewall mounted glow plug resistor behind the vacuum pump?

To answer your question premise. Voltage at the glow plug just means that you are getting power to it. The only way to test the glow plug for function is to do the Ohm check I showed. Or, remove the glow plug, put it in a vise and put 12 volts to it. Wear a face shield while doing this. If it turns bright red then it is good. Unless it is a Delco 60G don’t leave power to the glow plug longer than 15 seconds or it could burst. Which is why I suggested the face shield. I have had it happen to me.

 

[Keith_J]

If all eight glow plugs are burned out, you will measure 24 volts at the glow plugs when energized with the stock CUCV system.

 

[Barrman]

Keith, I tip toed around that can of worms with care I thought. But, you are correct.

 

[Keith_J]

Keith, I tip toed around that can of worms with care I thought. But, you are correct.

Per the 42 page technical paper on the glow plug system, the controller opens the solenoid connection at 16.2 volts measured at the solenoid. Probably because each plug draws over 8 amps and through the 18 gauge wire to each plug, there is a significant voltage drop.

 

[dougco1]

The glow plugs are needed anytime the inside of the cylinder is less than 159° according to a really long and boring paper Bosch published years ago. So, check your glow plugs and replace them if needed.

Here is a video of how to test them if you want to do that:

For those of us that are lazy or in a hurry, there is no need to remove all your glow plugs just to test them. Just unplug the wire to each plug and test continuity by grounding 1 lead and touching the other lead to the spade tip on the plug. If you show continuity your plug is good. If you don't have a volt meter you can use a simple test light the same way. Just hook the alligator clip of the test light to your + battery side and touch the probe tip of your test light to the spade tip on the plug. If it lights up your good to go.
If you have 1 or 2 plugs that test bad you can replace just them. If you have 3 or more bad plugs you should replace all 8 of them. That way they will have all the same resistance and last much longer

 

[Keith_J]

Yes, Doug, glow plug testing with a simple 12 volt trouble light is good enough for the majority of the time. Indirect injection has the glow plug in the middle of the precombustion chamber. Direct injection engines have the GP at the middle of the cylinder head with only a slight impingement of fuel on the plug. Glow plugs are only needed on DI engines below 45°F, even on smaller ones (under 500 cc per cylinder).

I defer to glow plug current draw. When cold, the CUCV draws over 100 amps combined. That causes a good drop in battery voltage, visible on the stock voltmeter.