617na manual glow/emergency start? - PeachParts Mercedes-Benz Forum

Fulcrum525 · #1 08-26-2011, 12:05 AM

Kind of a stupid question but i'm wondering if it's possible.

1982 617na (Which has been sitting for 6 months)

I went to test drive a car last night and it wouldn't start because the 80A fuse in the glow plug relay kept splitting when a start was attempted. I immediately thought either a bad ground or a bad relay. The current owner can't seem to figure out the issue and just said that the glow light stopped working one day. I really need to test drive this car before I even consider it but I can't really go through it myself until I get it home (IF) It's somewhat far away so I need a 'quick fix' solution to get it running at least once. Now, a couple of years ago we were working with a 603 glow plug and my father put the plug directly onto the positive terminal of a battery to test it. Sure enough the glow plug heated up like it normally would and turned red.

So here is my thought....is it possible to unplug the glow plugs from the harness/relay and heat them manually with a battery/jump pack and a pair of small jumper cables?

Planned Steps-
1. Disconnect the glow plug harness
2. Attach one side of the jumper cable to the positive terminal and the other to each glow plug for about 5 seconds each.
3. Repeat quickly on all 5 plugs.
4. Turn key and hope for the best.....

Would plugging in the block heater long before I get there help at all? Any dangers I should be aware of? Any other options or ideas would be greatly appreciated.

ashedd · #2 08-26-2011, 12:37 AM

well yes you could do that... you might be able to get away with just "glowing" a couple plugs. Also, my old SD would start w/o working plugs. Just crank and crank and crank while pumping the "gas". I would "jump" the batt while doing this.

destroy · #3 08-26-2011, 12:39 AM

if you put 12v across the plug the right way, provided they're still good they should get good and burnin' hot for ya. i know most will say it's a horrible idea but if the glow plugs don't work at all and the car just absolutely won't start you can always give it a tiny sniff of starting fluid. use that part at your own discretion, by the way.

here's what you need for glow plugs:

http://www.dieselgiant.com/glowplugrepair.htm

Diesel911 · #4 08-26-2011, 12:52 AM

You are overlooking something.
Most of the time when the Strip Fuse burns it turns out to be some problem with the Wires Going from the Glow Plug Relay to the Glow Plugs being Grounded because the Insulation is worn through or one of the Wires has come off of the Glow Plug and is touching the Block.
If the above was the case and you hooked the Glow Plug Wires up directly to the Battery something is going to burn.

Look at the Glow Plugs to see if there is a Wire Missing and trace the Glow Plug Wires from the Relay on down. Under there is a Clamp to steady the Wires. If the Rubber Sleeve on the Clamp is gone it could rub through the insulation and cause a short circuit.

Unplug the Connector that attaches the Glow Plug Wires to the Glow Plug Relay and turn the Glow Plugs on. If the Strip Fuse Burns without the Glow Plugs connected to it the Relay is no good.

Fulcrum525 · #5 08-26-2011, 12:58 AM

Quote:

Originally Posted by Diesel911

You are overlooking something.
Most of the time when the Strip Fuse burns it turns out to be some problem with the Wires Going from the Glow Plug Relay to the Glow Plugs being Grounded because the Insulation is worn through or one of the Wires has come off of the Glow Plug and is touching the Block.
If the above was the case and you hooked the Glow Plug Wires up directly to the Battery something is going to burn.

Look at the Glow Plugs to see if there is a Wire Missing and trace the Glow Plug Wires from the Relay on down. Under there is a Clamp to steady the Wires. If the Rubber Sleeve on the Clamp is gone it could rub through the insulation and cause a short circuit.

Unplug the Connector that attaches the Glow Plug Wires to the Glow Plug Relay and turn the Glow Plugs on. If the Strip Fuse Burns without the Glow Plugs connected to it the Relay is no good.

All good points. Unfortunately there wasn't any time to do proper diagnostics while I was there as the sun was going down and I didn't have any tools with me. It would have been nice if the seller had mentioned BEFORE I got there that the vehicle wouldn't start. (At least the starter motor works.....)

When I go back next week I'll need to get there much sooner and be completely prepared. My guess is that this guy won't be figuring out this issue anytime soon.

aaa · #6 08-26-2011, 05:32 AM

Just short the two posts on the fuse/relay with a screwdriver.

Fulcrum525 · #7 08-26-2011, 08:15 AM

Quote:

Originally Posted by aaa

Just short the two posts on the fuse/relay with a screwdriver.

Yeah i'm going to go with no on that one lest I overload something.....

kerry · #8 08-26-2011, 08:59 AM

You can bypass the relay and jump the plugs directly with a 'spider' cluster made from solid copper romex wire. Take 5 pieces, strip the insulation off the end--these ends will go in the plug at the end of the harness coming from the relay to the plugs. Then twist all five of the other ends together and run a jumper cable from there to the positive post on the terminal. Then you can heat the plugs at will.
But, first check for a short in the harness as jmentioned above.

Fulcrum525 · #9 08-26-2011, 09:12 AM

Quote:

Originally Posted by kerry

You can bypass the relay and jump the plugs directly with a 'spider' cluster made from solid copper romex wire. Take 5 pieces, strip the insulation off the end--these ends will go in the plug at the end of the harness coming from the relay to the plugs. Then twist all five of the other ends together and run a jumper cable from there to the positive post on the terminal. Then you can heat the plugs at will.
But, first check for a short in the harness as mentioned above.

Another good idea. So long as the harness is good of course (As mentioned) I think I may have some of that wire around too. Have to check next week.

winmutt · #10 08-26-2011, 09:17 AM

Uh people....

Take an ohm meter and pull the gp harness and measure resistance to ground on each gp. If nothing is shorted there then test at the fuse to see if its internal in the GP relay. 5 mins to do all of this. Jumping the GP's is a bad bad bad bad idea without testing some basics first.

Brian Carlton · #11 08-26-2011, 09:47 AM

Quote:

Originally Posted by winmutt

Uh people....

Take an ohm meter and pull the gp harness and measure resistance to ground on each gp. If nothing is shorted there then test at the fuse to see if its internal in the GP relay. 5 mins to do all of this. Jumping the GP's is a bad bad bad bad idea without testing some basics first.

This advice is correct. All prior posts have way too much risk of fire or engine damage.

Troubleshoot the system like a professional.

winmutt · #12 08-26-2011, 09:48 AM

Nothing says fun like blowing up a battery terminal

kerry · #13 08-26-2011, 09:56 AM

You guys losing your reading skills? Weren't there repeated references to checking the harness for shorts before jumping the plugs?

Brian Carlton · #14 08-26-2011, 10:00 AM

Quote:

Originally Posted by kerry

You guys losing your reading skills? Weren't there repeated references to checking the harness for shorts before jumping the plugs?

Apparently, if you are not extremely specific in stating what not to do, the engine becomes a pile of scrap............therefore the need for extreme clarity during situations of serious risk to hardware.

winmutt · #15 08-26-2011, 10:02 AM

Quote:

Originally Posted by kerry

You guys losing your reading skills? Weren't there repeated references to checking the harness for shorts before jumping the plugs?

Visual inspection is not all that is needed. The glowplug itself could be the issue. An ohmmeter would be the proper way to verify no short is present.