Glow Plug Question

[SolarSteve]

Thanks for the tips.  I just ordered 8 heat shields from GAP.  I think I am going to pull the injectors because I want to be sure the spray pattern is right as well as looking at the GPs.  I am hoping to find some bad GPs and hope its not a compression issue.

Its kind of hard for me to believe that it could be GPs though.  I just install brand new ones in July and the 1 I pulled looked great, but I guess if I have a leaky injector it could have burned the GP tip off...

If/when I pull the buss I will cut out the bottoms like you mentioned.

What is the exact amount of Ohm I should be looking for on the GPs if testing them while still installed?

Thanks

[theman53]

I don't know, but if you hook power to them and they glow red rather quickly I would say they should start that beast.

[SolarSteve]

Well, tonight when I get home or tomorrow morning I will pull the injectors and have a look.  If they all glow red and fast, I will double check the timing (cam), if that is good, I will be really stumped.  I can't see an engine running just fine, shut off and then compression dropping off in less than 24 hours of not running...

[burn_your_money]

It really sounds like you have some glowplugs burnt out. Check them all and report back. If they are all good, then do a voltage drop test.  Actually you may as well do a voltage drop test anyways...

Lots of people are lazy and only replace the 2 that are easiest to get to. So checking those 2 is almost pointless if you aren't checking the other 2

[rabbitman]

I think the bentley says to put the ohm meter on the beep setting and see if the gp has continuity, if it does it's good and if it doesn't it's bad.
However I had one that tested good using that method yet it failed to glow when hooked directly to a battery.

[SolarSteve]

It really sounds like you have some glowplugs burnt out. Check them all and report back. If they are all good, then do a voltage drop test.  Actually you may as well do a voltage drop test anyways...

Lots of people are lazy and only replace the 2 that are easiest to get to. So checking those 2 is almost pointless if you aren't checking the other 2

I will check all 4 tonight when I get home, but if I only had 2 working wouldn't it bang on the other 2 cylinders while cranking?  Giving me some sign of life...  Also, I replaced all four this past July when I swapped heads, but I will still check.

Thanks for all of the help.

[SolarSteve]

It really sounds like you have some glowplugs burnt out. Check them all and report back. If they are all good, then do a voltage drop test.  Actually you may as well do a voltage drop test anyways...

Lots of people are lazy and only replace the 2 that are easiest to get to. So checking those 2 is almost pointless if you aren't checking the other 2

If I can get a helper tomorrow I will do the voltage drop test, otherwise I will have to wait until Friday morning, I work swings and the wife has to watch the girls...

I am really hoping to find some bad plugs tonight...  I guess if I do the injectors with need some work.

Also, last month I installed a new battery and in the process I replaced the cable from the starter to the POS terminal.  The old one was fraying at the battery connection.

[burn_your_money]

How tight did you put the new glowplugs in? If you crank them down too tight they crap out very quickly. I forget what the torque spec is off the top of my head...

[SolarSteve]

I used the Bentley specs, I think it was something like 40 or 50 in/lbs.  I can't remember off hand.

Out of curiousity, why does over-torquing them cause them to burn out?  Do they contact the other side of the camber?

[Vincent Waldon]

Out of curiousity, why does over-torquing them cause them to burn out?  Do they contact the other side of the camber?

My understanding is that it cracks the internal insulation so that the element overheats.

[trev]

I CAN tell you with some grim experience, that too much torque on a Glow Plug can crack the boss that it screws into.

That little experience cost me a cylinder head. And too much time twisting a wrench in an unheated garage at 20 below.

I thought I had a glow plug issue at the time, and it turned out to be a hole in the fuel line, sucking air. Dumb dumb dumb.

The best mod I've seen around the glow plugs, was to run separate wires to each of them from a terminal strip on the firewall. Vince Waldon's, IIRC. Nice.

 Smoke is usually a good sign. It says that something is trying to burn, hopefully fuel.

 Gotta be something simple. All the wire to the shut off solenoid intact? Solenoid clicks on power on/power off?

It does have diesel in it, not gasoline? Camshaft timing checks? Air filter is not full of snow? Grasping at straws here. Tough to tell, without being there and seeing it.

 Cheers
  Trev

[92EcoDiesel Jetta]

This really sounds like a glow plug issue to me. Your mistake in diagnosing the problem is not checking all 4 glow plugs and  going off on a tangent. You probably have 1 or 2 bad glow plugs and the smoke is from the cylinders with good glow plugs partially combusting the fuel. Did you put in AC Delco or Champion glow plugs by chancet? They are junk and don't last.  One of the best tool I have to diagnose glow plug problems is a non contact  ammeter. It takes seconds to check if all glow plugs are working. I'll post some pics of it later

[SolarSteve]

Here is the update

I got home at 1am and it was about 15F so all I did was plug the block heater in.  This morning it was about 20F and I was reluctant to pull the injectors to look at the GPs, so the first thing I did was stick a hair dryer into the inlet of the air box and then I hooked up a small container of diesel fuel to the line that comes out of the fuel filter.  I was begining to think it might be a fuel problem.  The hair dryer was in and blowing for about 5 minutes while I hooked up the fuel.  I re-installed the GP relay (had it out to test it) and glowed the plugs for about 15 seconds, cranked it and on the second crank it fired up like there never was a problem...

So I am thinking that either the fuel filter was clogged or the fuel line (which was a little loose) was letting some air in.  So I let it run for until the fuel in the bottle ran out and I changed the fuel filter and installed a better clamp on the hose and got it good and tight.  I used a Mity Vac hand vac pump to prime the filter and started it again without the hair dryer and it started and ran just fine.

I shut it off cleaned everything up and let it sit for about 3 hours without any heat.  I went to start it up to go to work and it was just cranking again without starting.  After about 10 seconds of cranking it began to fire on a couple of cylinders and then came to life.

So, I am begining to think it might be the GPs again.  I guess there could have been some air still in the system, but I not sure.  I did drive it to work to today which consists of about 40 minutes on the highway and I am going wait 3 hours and try to start it in the parking lot.  If it was air then it should be out of the system by now.  If its the GP's I imagine I will have a hard time starting again.  I brought the hair dryer and an extenion cord with me!

Off hand I don't know the brand of GP I have in there, but they are from Prothe.  My first set from him worked just fine all last winter so I figured a brand new set installed this last July would be fine too.  Maybe not.  I am going to order a set from GAP tonight or does anyone have a better sugesstion as to whom I should get them from?

[rabbitman]

My money is now on junky gp's .

I bet the hair dryer did the trick. I had one gp burn out and it started ok and then missed for a little while, about a week later another gp fryed and then it would crank and crank and finally start and then miss real bad.
I changed 'em and it fixed it.

[92EcoDiesel Jetta]

Glow plugs from Prothe huh? Don't use anything except Bosch. If you can find Bosch Duraterms get them. It's not worth screwing around with junk with a critical part like a glow plug. Burning out prematurely is easy to stomach but if the tips fall off (this does happen with cheap glow plugs) you stand to blow up the engine. Hey, I have $80 worth of parts I bought from Prothe which I will never use. Do you want to take them off my hand at a discount?