Why would my GP's die so soon (Bosch)?
 

I go to start my car this morning and of course it would not start. I immediatley knew it had to be the Glowplugs. It would crank and crank and crank, but it wouldnt fire up. I couldnt test the resistance at that moment (because I was already late for work), but I got home today and checked and found 4 out 5 bad with readings of close to 2 Ohms. The thing is I replaced all 5 and the relay at about this time last year (~7,000 miles ago). All Bosch equipment. Why would they die so fast? A slight short somewhere? I thought it was peculiar a month or two ago when it was still relativeley warm and my car was rumbling a bit more on start up than it should have been. Shame on me for not testing earlier, but I honestly did not expect them too be bad so soon! I cant figure it out...Could my experiments earlier this year with the millivolt method have had anything to do with this ( i dont think so)?

i am fairly new to posting but i have read alot about reaming the holes to get the built up carbon out. and i would think if there is alot of carbon built up the GP's would over heat and burn up sooner.

Maybe them's ingine glow plugs :P

No inline GPs on the SDs.

youse guys means they line up the Glow plugs on the SD's? what's an ingine?
hey, I tink the new guy(or are you a girl?) has a pretty good guess.
how hard were the GP's to remove?
if they were pretty easy, maybe you have one of the sticking relays?
Maybe you have the afterglow upgraded relay and a weak set of plugs?
time to start testing stuff.
how long do the GP's stay energized on the glow cycle? Do they shut off after you start the engine?
John

I was suggesting maybe the Bosch GPs are made with the same quality as their Indian injectors.

6 year old BOSCH India GP, Injectors and IP still running fine, thousands of vehicles with the same combo run for over 200,000 miles before needing a service, till today, my GPs make my vehicle start in -15C weather when needed, mind you, even though general diesel quality in cities is now excellent here with additive added option, out of the cities the story changes drastically with naphtha added contaminated and dirty fuel, the BOSCH injectors and IP pumps tackle that quite well.

Possibly a short circuit glow plug has created a fault in the GP relay, which is now supplying too high a voltage to your glow plugs and burning them out?

On that note...
 

Over a year ago i purchased an 81 240d as my daily driver. the first month that I had it, I bought new glow plugs becuase I figured I had no idea how long those GPs were in there and I dont want to possibly be stranded for such a stupid and easy thing to fix. I bought Autolites...this is was a big mistake. I changed my bosch GP and saved them incase of an emergency and installed the autolites. Six months later my car wont start in the morning and I thought i was in a world of trouble becuase I knew that it couldn't be the GP. I tried to see if the GP relay needed replacing, pulled the battery to see if it needed to be replaced...the list goes on and on. After a couple hours I took my light tester and found that I had power to all the wires that attach to my glow plugs. I figured "what the ****...I'll pull the GP" to convince myself that they are good and move on. Three out of the four that I replaced less than six month prior were absolutly dead. And what pissed me off was that I didn't think to save the reciept to take them back. I took the original glow plugs that I saved for "emergencies" and installed them and for 8 months they have been in the 240. Knowing that the cold season is almost here, the other day, i figured I will pull them to see if they all still work. Sure enough my bosch GP that have been in that car for God knows how long, burn red hot in less than 3 seconds. Always use bosch and never get the ****ty autolites or any after market, american made piece of **** GP.
-Stephen

It probably would do no harm to ream out the glow plug holes prior to replacement. There is every possibility you may have gotten just some sub standard production run plugs as well. The newer plugs have increased in resistance not burnt out so it's hard to say what the cause was from my perspective. Unfortunatly you will have to try another set to find out if it was just poor quality plugs or not over time. The recommended brand has had consistency problems before I believe. Now as to the warranty thing. You keep you sales slip this time and use it six months down the road with the plugs you are removing now. Thats of course if they have a one year warranty to get a spare set. I would not want to really encourage unethical behaviour.:D

Well I ordered a set of 5 new ones and they should be here today. Thankfully we have had somewhat of a reprieve of the cold weather for today and at 46 degrees my car turned over instantly with just one plug working. Makes me think (or at least hope) that this is an indicator of good compression. Anyways hopefully I can change em out today.

Our '83 started in 12F with two working plugs. :D :D Cranked it for 40 seconds nonstop, huuuuuge cloud of white unburned diesel when it finally started firing and grumbling to life. We were amazed. Engine has almost no trace of blowby either at 279k :eek:

Question-
Where exactly are the GPs in a 1985 300 D turbo? I have the one that looks like a W. I want to see if there is carbon build up. I just bought this car (yeah!) and can't find service records history that say "GPs replaced".
Major maintenence service is overdue but will have to wait until January. Christmas gift buying for humans is a priority now.
Frankie

Alright. I changed the 4 bad GP's out yesterday during my lunch hour at work :) . Things look good now, but it still took some heavy cranking this morning in 15 degree weather. I guess its time for fuel filters and a lil bit of kerosene. 2 side notes: 1. Where can I get a new wire assembly that goes from the relay to the gp's (mine is old and the insulation is cracking all over the place, perhaps causing shorts here and there). 2. All of a sudden my speedometer has decided to not work. While I dont think it is related to my gp situation, I dont even know where to begin looking to solve this problem. Checked the fuses and they are all fine.