This is my first post.Just want to say this site is great.
I have a 2000 7.3 4x4 I checked my glow plugs today with my meter and what I found was that I had 0 ohms from battery ground to pins.I tested the passenger side first and all four came up with 0 ohms and I then did the driver side and they were .05 .04 .04. 04 . I beleive the passenger side is my problem? I read in another thread that you should have .01 at least but 0 is bad is this true.Any help would be great THANKS

 

What problem are you having? Is the truck hard to start?

Depending on the quality of the meter, it might not be able to tell the difference at that low of a reading or it might mean that the GP wires are shorted to ground. My #8 GP wire was against the pushrod and wore through to the bare wire. You can always pull the valve covers to take a closer look and ohm out the plugs directly (and retorque the rockers and injectors).

 

Did you ohm the injectors on the Passenger side(1,3,5,7). If they looked good we can't blame the .00 readings for the glow plugs on a loose connector. Not all 4 anyway. If the injectors ohmed OK it is time to pull the valve cover and check everything out. Might as well have new glow plugs ready or a way and place to get them while the VC is off.

Edit: Trevor, you must have hit submit as i started typing. Yeah, I'm that slow.

 

If all 4 are all 0 on one side, might be a possible UVCH issue.

The drivers side are bad too if they really read .05. They should read .6 at minimum.

 

I am having a real hard start in the morning hard crank not a quick crank. Put new batterys in last week had the old ones load tested and they both were bad 9 years on those batterys.Checked glow plug relay that checks out good.It's a good meter Fluke. I did meter out the injectors to and they all checked out good. Do you know if 0 ohms is bad? Thanks

 

0 ohms basically means no resistance. The wire is open.

 

0 is a dead short, which would draw lots of amps and probably is whats making the engine crank slow. Just for the hell of it, unhook one of the small wires on the GPR (glow plug relay) and see if the engine cranks faster. It would make more sense for them to fail with a high resistance, but I suppose they could fail low too. Sounds like its time to wipe any dirt off the top of the engine, pull the VC's and take a closer look.

 

If the wire was open, there would be infinite resistance. Most meters read will read "OL" or "---"on an open circuit. 0 ohms is a short.

 

Ok I will un hook one of the wires on the relay. The truck start fine after warm just when sitting over night.

 

Making accurate low-resistance measurements is a lot harder than it may seem. The most common problem is that digital multimeters, even good ones, don't have a lot of resolution on their low scales. What is the lowest ohms scale that your meter has? Since it's a Fluke, I'm guessing that the lowest range is 200 ohms.

Another problem is that when you get down in the sub- one ohm level, the resistance of the meter leads themselves starts to become significant. I wouldn't be surprised if the meter leads are a tenth of an ohm.

The best way to get an accurate low-resistance measurement is to apply a known voltage, and measure the current draw. If you can put an ammeter in series with the individual glow plug hot lead, then energize it, you can measure the current through it. At the same time, measure the voltage on the glow plug side of the ammeter. Divide the voltage by the current, and this will give you the glow plug resistance.

Volts divided by amps equals ohms.

To do this you will need an ammeter that can handle the current draw of the glow plug, which sounds like it's 20 amps or more. This could be a challenge. Many DMM's have a ten-amp range, but it sounds like that won't be enough.

 

Ok I went out this morning and did the test again.Set meter up then took readings ,wow what a difference I one that was .5 and the rest were .7 and 2 that were .8 can it be possiable that these were going one buy one ?

 

Again, that is not a big difference, and such differences could easily be accounted for by how good of a connection your meter leads are making on the terminals.

The only way to get an accurate measurement of resistances this low is with a four-wire method, as I outlined in my post above. Energize each plug individually (using the same voltage source), and measure the current drawn by each.

I'm certainly not a glow plug expert, but I'm guessing you don't have any failed plugs. Do they ever fail shorted? Seems like they would fail open, if anything.