Texas is getting cooler, and so I have been plugging the SDL in on nights where the temp is below 45, with the timer kicking on about 2 hours before I have to go to work. The car starts fine and I can get down the road good. I take it easy on these cold mornings until the temp reaches 80 then drive it normally.

Well, I havent plugged her in, since its 50-60 at night, but starting now is getting worse. It was 70 in the afternoon when I started it, you would have thought it was -10 outside. GP light still on for 2 seconds, so I count, and on my count, at about 14 seconds, the GP relay clicks off. So I start it, and the car barely stays running, belching white/blue smoke, stumbling etc.

I decided today to put new Glow Plugs in. I picked up 6 new Bosch plugs and replaced them one by one. Here's a pic of the plugs. I threw one away and didnt feel like digging for it.

Check out the broken plug, it was in #4. All the plugs did glow when I put my 12V Jumper box to each of them.....




So I installed 6 new Bosch Plugs (without removing the Intake Manifold) and started her up again, same thing, 2 second GP light, about 14 seconds when I hear the 'click' and starts and runs rough. Once its warmed up, it runs as good as it did when I adopted her.......

Oil Level is normal, Car has not used a drop of oil since the last oil change 2500 miles ago. I'm using Royal Purple Synthetic 15W40 Diesel Rated oil. Coolant level is fine and clean. Both Fuel Filters are new, Bolt on has 2 new o-rings on the shaft, Recent Diesel Purge, Checked fuel cap, no vacuum, actually was pressure when cap was taken off.

Both my other 300SDL and 300D (both 603s) have more than 2 second GP lights and start beautifully.

Where do I go now? Fuse in the GP box is good. Temperature Sensor?

Thanks in advance!

__________________
91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

Try swapping another relay in first. If you need a sensor, I have a few spares that I can give you

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Good Idea! It didnt even occur to me! I'll swap the sensor as soon as we beat t.u.

__________________
91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

lol, I have the game on too. Just picked up half of my parts and that refrigerator, off for more errands in a bit.

I'll be back before 5pm so ya can bum that brake flusher.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Have you used a multi meter to ensure voltage and current to each plug? Corrosion and interrupted wiring are very typical on these 20 year old vehicles. Pull the 6 pin plug with the larger six identical wires on the glow controller and ohm out each lead. You should see maybe .5 ohms at most. anything more, and you have current robbing resistance that would keep your plugs from reaching full temp. Keep in mind, if the engine is warm the resistance will be slightly higher, if it is cold, it will be lower. Also, even though the relay clicks, if the contacts in the relay are shot, you will get very little if any current to the plugs.

If this car runs fine, i.e., nice and smooth hot, and you have checked each lead and plug, the only thing left is the glow controller itself, the contacts in the relay are corroded or burned. Also make sure the strap fuse isn't broken and your not seeing the separation. Like the colored fuse in the fuse box, they separate or the contacts under the strap become corroded and again, high resistance and no current.

PS, did you ohm out and current test the old plugs? Cherry red, favoring white hot in 10 seconds with 14 volts. The sensor is a ghost chase if you don't have after glow, 99% sure you don't have after glow. No after glow, no coolant sensor for the glow plugs. GHOST CHASE. It's all in the glow relay. CHECK THE PART NUMBER, CHECK THE PRINTS, CHECK THE BOOK!

Good Luck,
MG

__________________
Mark
========
THE WHITE FLEET
2016 GLE300d 4-MATIC 38K BROWN!
2012 S350 Bluetec==94k WHITE

2007 ML320 CDI==166K WHITE (FOR SALE)

Under new management:
2005 E320 CDI--140K--WHITE
1995 E300-Diesel-133.5K--THE CAR IS BLUE
1986 300SL--97.5K (European) AND WHITE. Back in Europe!
1991 190E 2.3-73K California Perfect.--WHITE
1995 E320-Wagon-159K--WHITE (recently scrapped)
1987 300D Turbo-213K--WHITE
1987 190D 2.5 Turbo-288K--WHITE

Anything between .8 and 1.2 ohms is perfectly acceptable. Rarely will the resistance on older hardware be anywhere near .5 ohms.

I tested all the plugs (except the messed up one) and they were all at .9 Ohms. I also hooked them up to a booster box and within 5 seconds they were all glowing cherry red and very hot.

I checked wiring to each plug from the Plug relay harness and everything was good. Wiring looked good.

Strap fuse is good.

Interestingly enough, I removed the Glow Plug Relay from my 86 SDL and put it in my 87 (EPC SHows the same Part number) and Voila, the Glow Plug light stays on longer now and the car starts good again. I understand that I can install a 90-91 SDL Glow plug relay and 90-91 Plugs with the afterglow feature, is that correct? The 90-91 Relay is actually about a buck cheaper than the 86-87 relay!

__________________
91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

On the original relay, 14 seconds should be perfectly acceptable to get a decent start without smoke or roughness unless it's very cold. You definitely were not getting that......even with a brand new set of plugs.

So, I'm going to take a WAG and suggest that the relay was not providing power to all the plugs. Additionally, the 14 second time limit is not proper. These relays should remain on between 30-40 seconds.

I'll bet the relay will give problems if installed in the '86. If you do it, see if you can verify voltage to each plug, independently. I realize that the task is near impossible on a 603, so, we'll probably not get to the bottom of this issue.

BAD PLAN

Pin 6 of the smaller plug (5 is unused) is the coolant sensor. Without the external input to the later glow controller, it doesn't have a managing input to regulate time of operation. I would believe it would only glow 2 seconds or not at all. (fault test would show open pin 6 and may self protect and not glow) The no afterglow units rely on the internal temp sensor in the glow control relay itself. Also, there are vertical prechambers in your engine vs. oblique prechambers 5°/180° or 5° with 60 second or 15 second afterglow in the vehicles equipped with afterglow. There are no less than 3 different plugs depending on application and prechamber installation.

Dependent on glow controller temperature, at -30°C glow time is 24-30 seconds, after which the internal safety cut out terminates glow. At +30° C, glow time is 2-4 seconds.


Good Luck, nice job on the troubleshooting!

MG

__________________
Mark
========
THE WHITE FLEET
2016 GLE300d 4-MATIC 38K BROWN!
2012 S350 Bluetec==94k WHITE

2007 ML320 CDI==166K WHITE (FOR SALE)

Under new management:
2005 E320 CDI--140K--WHITE
1995 E300-Diesel-133.5K--THE CAR IS BLUE
1986 300SL--97.5K (European) AND WHITE. Back in Europe!
1991 190E 2.3-73K California Perfect.--WHITE
1995 E320-Wagon-159K--WHITE (recently scrapped)
1987 300D Turbo-213K--WHITE
1987 190D 2.5 Turbo-288K--WHITE

Brian and Mark,
Thanks for the troubleshooting tips, as you Brian, predicted, when I put the relay in question from the 87 to the 86, I was treated to a 2 second light. Running the 86 Relay in the 87 right now until the new one arrives! The original relay was dirivng me nuts because the light would go out immediately, i.e. 2 seconds, but the relay would 'click' signaling it was shutting off after a period of 14 seconds.

With the swapped relay out of the 86 to the 87 (the car in question), the light stays on for 6-10 seconds.

Mark, thanks for the heads up on the relay. I'll order the correct relay on monday!

I think maybe the car is telling me it wants to be driven daily, she gets jealous when I drive the dodge.....

__________________
91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500