Kicking myself for making this mistake. What did I do? - Page 3 - PeachParts Mercedes-Benz Forum

funola · #31 06-21-2017, 09:53 PM

Googling found this diagram of 92 300D http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1992/300D/SYSTEM%20WIRING%20DIAGRAMS/4106.pdf

I'd suggest buzzing out and verifying the wiring with either a test light or ohm meter.

jake12tech · #32 06-21-2017, 10:30 PM

Quote:

Originally Posted by funola

Googling found this diagram of 92 300D http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1992/300D/SYSTEM%20WIRING%20DIAGRAMS/4106.pdf

I'd suggest buzzing out and verifying the wiring with either a test light or ohm meter.

Funola, thank you so much for posting that. Huge help.

I was also able to stop by my garage and look at the harness.

Here's the glow plug relay. I have everything properly hooked up here it appears.

This is a connector from the positive harness I can't figure out where it goes and don't know what it does.

I also have this connector that isn't hooked up from the positive harness. No clue where it goes or what it does.

I also have two ring terminals hooked up to the starter on the back of the stud. One small, one large. Largest connector in the back, smallest on the front.
This is what I mean by ring terminal to prevent confusion.

I also have this what appears to be a ground next to the studs where the glow plug relay mounts.

I tried to see if the car would crank in neutral, but it does not. I checked the ground strap between chassis and bellhousing. It is OK. I checked the power distribution box. It is OK. I have power at the starter.

compress ignite · #33 06-21-2017, 11:59 PM

I want you to Personally and Visually verify that the Ground connection
labeled: "Ground Connection at Left front wheel-well"
Wire insulation color BROWN
[The schemetic says: G100] [FUNOLA'S schematic]

Is present AND the Wire shows continuity from the GP Relay to the Clean.
Bright and Tight grounding stud!

Also , Look @ Picture from FSM for Starter Installation (From R+R) HERE:
http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD2/Program/Chassis/15-7100.pdf

You'll note the Big and little wires go to Two(2) different studs on the Starter's "Bendix"

SEE page 111 Here:

http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/ETM/ETM.pdf

moon161 · #34 06-22-2017, 12:22 AM

Those mystery connectors look like they go to the block temp sensors that determine glow duration.

spock505 · #35 06-22-2017, 04:56 AM

This looks very much like the oil level sensor located on sump, have you connected anything else to that as could be your problem ?

dieselbenz1 · #36 06-22-2017, 08:48 AM

It's not entirely clear to me if you just want to hear your engine running or put everything back into proper order. Anyways attached is your connector locations.

http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/ETM/wire_plug.pdf#page=4

jake12tech · #37 06-22-2017, 08:57 AM

Quote:

Originally Posted by spock505

This looks very much like the oil level sensor located on sump, have you connected anything else to that as could be your problem ?

I believe so, that's what I was thinking.

Quote:

Originally Posted by moon161

Those mystery connectors look like they go to the block temp sensors that determine glow duration.

I think you are onto something.. I will have to check that later.

Quote:

Originally Posted by compress ignite

I want you to Personally and Visually verify that the Ground connection
labeled: "Ground Connection at Left front wheel-well"
Wire insulation color BROWN
[The schemetic says: G100] [FUNOLA'S schematic]

Is present AND the Wire shows continuity from the GP Relay to the Clean.
Bright and Tight grounding stud!

Also , Look @ Picture from FSM for Starter Installation (From R+R) HERE:
http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD2/Program/Chassis/15-7100.pdf

You'll note the Big and little wires go to Two(2) different studs on the Starter's "Bendix"

SEE page 111 Here:

http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/ETM/ETM.pdf

WOW! Okay! This has clarified a lot. I have it BACKWARDS. I have two ring terminals connected on the SAME stud.. Most likely what's going on here with my no crank.

I also verified I DON'T have that "brown" ground on the wheel housing which is in my picture. I let a buddy of mine assist in pulling the motor when I wasn't there cause I was at work and had a deadline and it looks like he damaged it

. I believe THAT wire (G100) connects as well to the glow plug relay with a washer. Am I correct? If so, I was sending straight POWER to that glow plug relay and probably why the last one went up in smoke!

ROLLGUY · #38 06-22-2017, 10:50 AM

Another thing to check if it does not crank is the neutral safety switch. It could be bad, and won't allow the starter to crank in any gear selection.

funola · #39 06-22-2017, 11:00 AM

Quote:

Originally Posted by jake12tech

I believe so, that's what I was thinking.

I think you are onto something.. I will have to check that later.

WOW! Okay! This has clarified a lot. I have it BACKWARDS. I have two ring terminals connected on the SAME stud.. Most likely what's going on here with my no crank.

I also verified I DON'T have that "brown" ground on the wheel housing which is in my picture. I let a buddy of mine assist in pulling the motor when I wasn't there cause I was at work and had a deadline and it looks like he damaged it

. I believe THAT wire (G100) connects as well to the glow plug relay with a washer. Am I correct? If so, I was sending straight POWER to that glow plug relay and probably why the last one went up in smoke!

I can't tell from your description of "I have it BACKWARDS" on how it was connected. If you can describe it per the wiring diagram it would help in understanding why the glow plug relay smoked. Sending straight power to the glow plug relay should do no harm, factory wiring already does that.

One possibility is that if you are missing ground G100 Compressed Ignite spoke of (actually G103 per the diagram), which is needed for the starter motor's heavy current draw, the ground path for starting is diverted to other lesser grounds, i.e. grounds with much smaller sized wires. The device in the path of those smaller sized grounds will smoke at the weakest point within those devices when the starter motor is cranked, with no hint of starter turning because it did not get enough power/current. Aka "sneak path" in elec. jargon.

jake12tech · #40 06-22-2017, 11:43 AM

Quote:

Originally Posted by ROLLGUY

Another thing to check if it does not crank is the neutral safety switch. It could be bad, and won't allow the starter to crank in any gear selection.

Quote:

Originally Posted by funola

I can't tell from your description of "I have it BACKWARDS" on how it was connected. If you can describe it per the wiring diagram it would help in understanding why the glow plug relay smoked. Sending straight power to the glow plug relay should do no harm, factory wiring already does that.

One possibility is that if you are missing ground G100 Compressed Ignite spoke of (actually G103 per the diagram), which is needed for the starter motor's heavy current draw, the ground path for starting is diverted to other lesser grounds, i.e. grounds with much smaller sized wires. The device in the path of those smaller sized grounds will smoke at the weakest point within those devices when the starter motor is cranked, with no hint of starter turning because it did not get enough power/current. Aka "sneak path" in elec. jargon.

By having it backwards, I mean I have both ring terminals connected on the same stud on the starter. They are not separated on different studs like they are supposed to be in the starter installation compress_ignite posted.

The ground for G100 attaches to the glow plug relay correct? Cause that ground I am missing and it is very damaged as you see in the picture i posted before above.

This is where G100 attaches with the red arrows? Cause that's what it looks like in the diagram.

I hope I'm descriptive as possible, thanks again for the help. This may be saving me $500 I don't really have

ROLLGUY · #41 06-22-2017, 12:04 PM

Quote:

Originally Posted by jake12tech

By having it backwards, I mean I have both ring terminals connected on the same stud on the starter. They are not separated on different studs like they are supposed to be in the starter installation compress_ignite posted.

The ground for G100 attaches to the glow plug relay correct? Cause that ground I am missing and it is very damaged as you see in the picture i posted before above.

This is where G100 attaches with the red arrows? Cause that's what it looks like in the diagram.

I hope I'm descriptive as possible, thanks again for the help. This may be saving me $500 I don't really have

The arrows are pointing to the power wire for the GP relay. That red wire is + 12v and goes to the junction block, NOT TO GROUND!

funola · #42 06-22-2017, 12:13 PM

I think I know why you are confused. I don't understand this statement from Compressed Ignite:

"I want you to Personally and Visually verify that the Ground connection
labeled: "Ground Connection at Left front wheel-well"
Wire insulation color BROWN
[The schemetic says: G100] [FUNOLA'S schematic]

Is present AND the Wire shows continuity from the GP Relay to the Clean.
Bright and Tight grounding stud!"

The G103 ground is on the right rear shock tower and should not go to the GP relay! Follow the battery negative cable from the battery to where it terminates and that's where G103 is located.

How were you able to "have both ring terminals connected on the same stud on the starter"? They have 2 sizes of ring terminals, one needs a 17 mm wrench and the other probably an 8 mm. Did you put both terminals on the smaller stud? If so, there would be no power to the starter motor and it would explain why it did not crank.

At this point I would make sure you have G103 and wires that's been messed with per the wiring diagram by buzzing it out first. Install the ring terminals on the starter correctly and check that you have no shorts anywhere in the circuit and it should crank.

jake12tech · #43 06-22-2017, 12:37 PM

Quote:

Originally Posted by ROLLGUY

The arrows are pointing to the power wire for the GP relay. That red wire is + 12v and goes to the junction block, NOT TO GROUND!

I did trace that wire to the junction block.. There shouldn't be any ground attached to that with the glow plug relay power cable right? I'm confused where g100 goes to.

Quote:

Originally Posted by funola

I think I know why you are confused. I don't understand this statement from Compressed Ignite:

"I want you to Personally and Visually verify that the Ground connection
labeled: "Ground Connection at Left front wheel-well"
Wire insulation color BROWN
[The schemetic says: G100] [FUNOLA'S schematic]

Is present AND the Wire shows continuity from the GP Relay to the Clean.
Bright and Tight grounding stud!"

The G103 ground is on the right rear shock tower and should not go to the GP relay! Follow the battery negative cable from the battery to where it terminates and that's where G103 is located.

How were you able to "have both ring terminals connected on the same stud on the starter"? They have 2 sizes of ring terminals, one needs a 17 mm wrench and the other probably an 8 mm. Did you put both terminals on the smaller stud? If so, there would be no power to the starter motor and it would explain why it did not crank.

At this point I would make sure you have G103 and wires that's been messed with per the wiring diagram by buzzing it out first. Install the ring terminals on the starter correctly and check that you have no shorts anywhere in the circuit and it should crank.

Yes, I have both wires on a smaller stud on the starter. The one is a 13mm nut not sure about the other one. I will have to see.

Where does the ground for g100 go to? Anyone know? That is just damaged and cut and want to figure out where that goes to. I don't know if that attaches with the power cable on the glow plug relay.

funola · #44 06-22-2017, 01:02 PM

Quote:

Originally Posted by jake12tech

......................

Where does the ground for g100 go to? Anyone know? That is just damaged and cut and want to figure out where that goes to. I don't know if that attaches with the power cable on the glow plug relay.

Follow the brn wire at G103 on the diagram and that's where it goes to. Grounds (usually blk and brn wires) should not go to + (red wires), that's called a short and will smoke the wires and start fires.

jake12tech · #45 06-22-2017, 01:41 PM

Quote:

Originally Posted by funola

Follow the brn wire at G103 on the diagram and that's where it goes to. Grounds (usually blk and brn wires) should not go to + (red wires), that's called a short and will smoke the wires and start fires.

Thanks for the tip. G103 is connected, just can't figure out where the g100 goes to. It is damaged and is cut in the photo above. It's the left wheel housing side (driver side) next to the studs the glow plug relay mounts on. I can't figure out where it goes even on the diagram