No start "after" Glow plugs swapped - PeachParts Mercedes-Benz Forum

aquaman0001 · #1 10-12-2013, 08:16 PM

Good evening all,
The 87 300SDL was starting rough in the morning(50F) and no GP light so I decided to test the glow plug circuitry for continuity. GP 2 and 4 were high so I changed them with Bosch brand plugs.
Steps to removal:
-disconnected batter
-Removed Intake
-took linkage off that is attached to intake
-Removed glow plugs
-installed new GP
-Tested continuity on all GP(all test around .4-.5 ohms)
-Turned key to test GP light. Light came on. Life is good
-Put intake back on
-hooked linkage back to Intake
-hooked battery back up

Went to start.
Cranks like a champ but it will not turn over. Ton of smoke.
I am on a hill. Front of car is pointing toward top of hill.
Shut off valve position is horizontal. normal?
No GP light. But but the temp was creeping up to around 67F.

Beside the rough starting the car has been running great.
What could I have knocked loose that would cause the car not to start?
I did not change any fuel filters. I did change a headlamp bulb when I was swapping out the 2 GPs. Any suggestions would be greatly appreciated. I am sure I am just overlooking something obvious.

Cheers,
A

kerry · #2 10-12-2013, 08:50 PM

You should have a glow plug light I believe. Check for voltage at the plugs with the key i the glow position.

vstech · #3 10-12-2013, 09:26 PM

according to your sequence of assembly... you tested and received a glow light, before you reconnected your battery...

I'm guessing you attached it temp to verify the light was working, then disconnected it again to reassemble the intake...

if so, the wire routing could have hit the intake, and blown the fuse as soon as you tried to glow again after the Intake was installed... get out a light, and look carefully at each wire connector, and follow each wire, and verify none got caught between some metal, or lodged against the manifold.

does your glow light still work?

aquaman0001 · #4 10-12-2013, 09:53 PM

No light at all. It was warm. I will test it again now that the temperature has dropped.
A

kerry · #5 10-12-2013, 09:55 PM

What is the relevance of the temperature?

aquaman0001 · #6 10-12-2013, 10:12 PM

No GP light. Just trying to supply as much information as possible and to make sense of something that tested great but now does not work. I thought all of the GP wiring is below the intake manifold but I will take a closer look. If there was a wiring issue would it not show up when I did the tested the continuity? I will test the relay for voltage.
A

kerry · #7 10-12-2013, 10:17 PM

To my knowledge the GP light is not dependent upon temperature.

TnBob · #8 10-12-2013, 10:29 PM

My GP light comes on anytime I start up.

Id pop both connectors on the GP relay and reseat them

sixto · #9 10-12-2013, 10:50 PM

Shut off lever should be up. Disconnect the vacuum line at the shutoff actuator then start the engine.

An afterglow relay might not light or light so briefly that you miss it when the engine's hot if it's wired to a proper coolant temp sensor.

Did you check resistance across the glow plug terminals or between the glow relay connector and ground? Did you check the strip fuse? Do you get 12V at the big glow relay pins when you turn the key to glow?

Sixto
87 300D

aquaman0001 · #10 10-13-2013, 02:26 PM

Rain finally stopped. The strip fuse in the glow plug relay looks like it arced and was cracked at the arc. So my 2 questions are:
1. Does anyone have a part number or know who carries them
2. Should I be concerned that the fuse arced?

Thanks,
A

sixto · #11 10-13-2013, 02:49 PM

It's an 80-amp fuse similar in shape to the external 30-amp fuse for the blower if your car has that upgrade. Part number is 000 545 03 34. I don't see the fuse listed at Autozone or O'Reilly but a more specialized store might match the shape with the blower fuse. Or call Peachparts and have them put a few in an envelope for you for first class postage.

If indeed the battery was disconnected while working on the glow plugs, you might have terminals in contact with ground, or the harness is tired and moving it caused insulation to crack. Test continuity to ground of each glow plug terminal of the big connector at the glow relay. The connector pins are numbered if you need to trace a ground fault.

Sixto
87 300D

aquaman0001 · #12 10-13-2013, 02:56 PM

Thanks Sixto,
I went to order the parts here but the 3 day shipping was pretty high. I will call them and ask about first class postage. I will recheck for continuity to the plug terminals before I reinstal the fuse.

A

aquaman0001 · #13 10-13-2013, 03:00 PM

Sixto,
Do you think an inline fuse would work? An inline seems like a good alternative but fitting may be an issue.

A

sixto · #14 10-13-2013, 03:09 PM

I suppose you can use the screw terminals to attach a quality inline 80-amp fuse such as for a big @$$ amplifier. Is there a wrecking yard that might have 300Ds or SDs with glow relay fuses to be be liberated? Any MB Diesel since the early '70s uses the same fuse.

Sixto
87 300D

kerry · #15 10-13-2013, 04:01 PM

You could temporarily use a jumper wire to get it started.