Glow Plugs

Everyone should read this.

http://beru.federalmogul.com/sites/..._all_about_glow_plug_pfmbu1435_-_en_lores.pdf

Really good info on the Beru's.

It's really good info on what they currently have/are doing.

I'm still not sure from that PDF how our ZD9s are built, and what properties they have.

I am thinking it might be worthwhile to design a "GN" style system; it probably wouldn't be too hard to build a small controller with 8 PWM circuits and feedback resistors.
Your controller could then sense the temperature of each glow plug and maintain it as long as needed, and more importantly the failure of one glow plug would not throw the entire system out of whack.

It might even be possible to do it far more simply, using integrated PWM modules and a few resistors with no controller, for lower cost.

After reading the document in the original post, I would like to ask, for my (non-turbo) 1988 F-250's 7.3 IDI diesel:

1. Is this a AnteChamber, Turbulence Chamber or Direct Injection engine?

2. A number of different types of glow plugs are described. What type(s) does my engine take?

3. Will it take these "BERU" type glow plugs?

And then on another note:

4. I noticed that in recent cold weather it took several tries to get my engine started. On this occasion the weather had been below freezing for an extended period but the morning sun had warmed the engine compartment while the temperature of the engine itself would have still been below freezing.

This curious/unusual difficulty in starting the engine that day made me think that the sensor that determines how long the glow plugs operate before the wait to start engine light goes out must be on the outside of the engine where the engine compartment temperature was significantly warmer than the engine temperature itself perhaps causing the glow plugs to "turn off" prematurely. Is that possible?

Thanks for considering my newbie questions.

-- ****

rempfer said:

After reading the document in the original post, I would like to ask, for my (non-turbo) 1988 F-250's 7.3 IDI diesel:

1. Is this a AnteChamber, Turbulence Chamber or Direct Injection engine?

2. A number of different types of glow plugs are described. What type(s) does my engine take?

3. Will it take these "BERU" type glow plugs?

And then on another note:

4. I noticed that in recent cold weather it took several tries to get my engine started. On this occasion the weather had been below freezing for an extended period but the morning sun had warmed the engine compartment while the temperature of the engine itself would have still been below freezing.

This curious/unusual difficulty in starting the engine that day made me think that the sensor that determines how long the glow plugs operate before the wait to start engine light goes out must be on the outside of the engine where the engine compartment temperature was significantly warmer than the engine temperature itself perhaps causing the glow plugs to "turn off" prematurely. Is that possible?

Thanks for considering my newbie questions.

-- ****

Click to expand...

1: Antechamber, they're usually called Precombustion chambers or "Precups" around here. Also, these engines are called IDI's because they're In-Direct Injection

2: Motorcraft ZD-9 is what you want for these 7.3's. You can special order them from O'Reilly's, Rock Auto, or a bunch of other places. Beru makes them for Motorcraft, they're the exact same thing; it's a Motorcraft box with Beru glowplugs in them.

3: These engines take ONLY these Motorcraft / Beru glowplugs. DO NOT let the parts counter guy talk you in to Bosch, Autolite, Champion, Diesel RX, or ANY OTHER GLOWPLUG. Motorcraft / Beru ZD-9 is the ONLY glow plug for these engines, ALL others WILL in very short order (often in 1-3 start cycles) and force you to pull the heads off the engine.

(Anyone who says they've been running Autolite's for years without problems is clearly a deep cover agent sent by Chevy to sabotage our trucks. Be warned!)

4: The GP controller uses a coolant temperature sensor towards the front of the engine to help determine how long to glow the plugs, but if the sensor is bad I don't know how the GP controller would act. Someone who knows what they're doing will probably chime in on this. Someone with a clue chimed in, so ignore me while I wear the cone of shame. I'm a derp and should know better.

Golden Helmet said:

4: The GP controller uses a coolant temperature sensor towards the front of the engine to help determine how long to glow the plugs, but if the sensor is bad I don't know how the GP controller would act. Someone who knows what they're doing will probably chime in on this.

Click to expand...

The controller does not use a coolant sensor to sense the temp of the engine. The only way the controller knows the temp of the engine is by sensing how much current is flowing to the glowplugs. The glowplugs will draw more or less current depending on how hot they are. The controller monitors the current by reading the slight voltage drop across a shunt (some people call it the "z bar strip) mounted on top of the controller. This design works well but has one fatal flaw; If one glowplug burns out, then the system will not draw enough current and the controller brain thinks the engine is warm and will not glow the plugs long enough to start the engine. The engine will start on 7 glowplugs, I have started mine on 5 glowplugs in the winter. But the original glow plug controller will not allow this.

rempfer said:

4. I noticed that in recent cold weather it took several tries to get my engine started. On this occasion the weather had been below freezing for an extended period but the morning sun had warmed the engine compartment while the temperature of the engine itself would have still been below freezing.

Click to expand...

The only advice I can give, your idi diesel pickup is not going to fire off like a fuel injected gas engine. It's not even going to fire off like a carbed gas engine. These diesels are harder to start than other engines. Some diesels fire right off, some don't. I don't care how warm it is outside, these idi's always like some glowplug time before they start. The colder it gets, the more cranking will be needed to get them to start. Consider it something to live with, if you have ever ran diesel tractors and other equipment, you get used to it, the idi is really no different than a diesel backhoe or skidsteer as far as starting.

My work truck is a 09 6.0 f350, and it starts right up whether I let it glow for awhile or not. But it has a different fuel injection system on it also.

franklin2 said:

The only advice I can give, your idi diesel pickup is not going to fire off like a fuel injected gas engine. It's not even going to fire off like a carbed gas engine. These diesels are harder to start than other engines. Some diesels fire right off, some don't. I don't care how warm it is outside, these idi's always like some glowplug time before they start. .

Click to expand...

Absolutely no issues with mine. On a warm day I have no need for GP's.

Mine 'bump' starts as long as glowplugs are in good repair. That's w/o block heater plugged up.
I do have DB starter also, so it spins quick also. Does make a difference between original and gear reduction type starter.

Thanks for the read Russ!!

So, I just thought I'd add an extra data point here:
Champion glow plugs(CH84 for 7.3 idi). I'm not sure quite who makes them, but they are often the only ones available at the parts store.
As such, two of my trucks came with them installed.
I've pulled two sets worth at this point. None bulged at all or cracked.
On both trucks, at the time I decided to pull the glow plugs(due to hard starting issues), I've found a single bad glow plug.

Not wanting to spend the money to replace the entire set, I just got two more of the same to replace the dead ones; we'll see how long the complete set lasts.

After reading the Beru guide, I decided to test my new glow plugs before installing them.
The first, I took a 12-ga piece of wire and connected it to a 12V battery. I held it on the terminal until the entire glow area got red hot, then disconnected it.

I found that the glow plug bulged a little near the tip. I think that this can be attributed to water/moisture in the ceramic packing material.
After letting it fully cool, I got it red hot a couple more times(though /less/ hot) and it continued to work correctly with no more bulging.

The second one, I decided to be a little more gentle with. I heated it up slowly - holding for perhaps 5 seconds, then letting it cool down a little, heat it back up etc. It heated up red hot as well, and did /not/ bulge.

Anyway, I installed the second one in my current DD. It improved starting immensely(well, yeah...); fires right off from 20-30F on the first try, not being plugged in.
With 7 working, it was smokey and usually required 10-15 seconds of cranking.

The first one, I was going to return as defective(having never installed it in an engine), but then I decided 'screw it', and installed it on cyl #2 of my other truck(while bulged a little, it wasn't enough to interfere with anything).

Once I got good connections on all the glow plug terminals, it fired up on it's own after having sat for a few weeks, with what seems like an iffy starter.

Now, we'll see what happens long term.
Just a reminder - I /do/ know what I am doing(I like to experiment with things), and am no stranger to pulling heads and rebuilding motors... I'm not going to pull these glow plugs as long as they keep starting the truck, then I will report on the results.


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Might as well report on another datapoint: Diesel RX DRX00088, spade style.
For the last 3-4 years, I've run an 88 with a pushbutton setup. I used a 9th glow plug in the cab so I could tell how hot they were getting, 8 spade-style glow plugs, custom wiring harness, and the resistor/relay off a 7.3 controller.

During that time, I've managed to kill a number of them. It's been user error("OH SH*T it's not starting, give it more glow plugs!" with gelled fuel) most of the time.
While they may or may not be the best when it comes to holding up under adverse conditions(Looks like the Beru handle high voltage for a long time better), I did not have any bulge or crack. Period.

I'm not going to say that they will work correctly with a proper controller, but I did use them for several years with a pushbutton setup.