96 E300 Diesel Starting problems

[Ghost]

I thought I would see if anyone over here could help me with my DD Diesel problem. It's intermittent and seems to have no consistency what so ever. 96 E300 Mercedes Benz Diesel. After warming the glow plugs when I turn the key to the start position it does nothing. Some times I can turn it off do it again and she fires right up. Lately its gotten worse and doesn't want to start more then start. I have an electrical schematic but its greek to me. Anyone ever work on one of these? :banghead:

 

[87manche]

you checked the starter right?

otherwise it sounds like a relay with bad contacts.

 

[Ghost]

you checked the starter right?

otherwise it sounds like a relay with bad contacts.

Well define check starter.... did I pull it off and take it to be tested? No. It works perfect when it works. I am thinking about jumping the starter to test it when I get home from work today. I looked in both boxes for a starter relay and could not find one.

Benzworld thread: http://www.benzworld.org/forums/w210-e-class/1965353-96-e300-diesel-no-start.html

Electrical posted:

http://autolib.diakom.ru/CAR/Mercedes-Benz/1996/E300/SYSTEM WIRING DIAGRAMS/5864.pdf

 

[87manche]

works perfect when it works.


sounds like every bad starter solenoid I've ever had.

 

[87manche]

looking at your wiring diagram, it's not complicated

When you turn the key the "pulse module" gets power. I'm unsure what the purpose of te pulse module is, but it's what actually controls your starter. I'd say that's mercedes fancy speak for starter relay.

it looks like the pulse module also powers the ea/cc/isc module from the same wire that goes to the starter solenoid. quick google says that's some sort of idel speed control thing. probably gets the signal form the start and sets the idle control at a high idle. I'd say not the issue, as that's just a sense wire.

From there it rolls through the backup lamp switch, which is probably some sort of neutral safety switch jobby. From there a violet/white wire goes to the starter solenoid.
I'd do my best to get a test light on that so I could see if the starter is getting power when it fails. If it gets 12V everytime you try to start then I'd peg the starter as faulty. If it doesn't you'll need to track back ot the backup lamp switch, see if you've 12V there. Continue working the circuit back until you get to the ignition switch. It's all violet wire from the ignition switch to the backup lamp switch.
You can ignore the other wire that goes to the glow plug relay. That's a wire that tells the timer to cut the glo plugs because you've turned the key to start.

 

[Ghost]

looking at your wiring diagram, it's not complicated

When you turn the key the "pulse module" gets power. I'm unsure what the purpose of te pulse module is, but it's what actually controls your starter. I'd say that's mercedes fancy speak for starter relay.

it looks like the pulse module also powers the ea/cc/isc module from the same wire that goes to the starter solenoid. quick google says that's some sort of idel speed control thing. probably gets the signal form the start and sets the idle control at a high idle. I'd say not the issue, as that's just a sense wire.

From there it rolls through the backup lamp switch, which is probably some sort of neutral safety switch jobby. From there a violet/white wire goes to the starter solenoid.
I'd do my best to get a test light on that so I could see if the starter is getting power when it fails. If it gets 12V everytime you try to start then I'd peg the starter as faulty. If it doesn't you'll need to track back ot the backup lamp switch, see if you've 12V there. Continue working the circuit back until you get to the ignition switch. It's all violet wire from the ignition switch to the backup lamp switch.
You can ignore the other wire that goes to the glow plug relay. That's a wire that tells the timer to cut the glo plugs because you've turned the key to start.

Now I feel dumb.... Yea I figured the "pulse module" was a relay but I sure didn't see what I call a relay when I looked in the compartment where it's supposed to be. My plan Sunday when it I had help and it decided to work was try and trace the 12v from the starter. That helps a lot. Electrical diagrams confuse me. I never would have guessed VIO was violet..... duh! Thanks now at least I have something to go on.

 

[Ghost]

Ok so it failed again and I put the test light on it. I also feel certain its not the starter solenoid because I could jump the solenoid with a screwdriver. This is what I think I have determined. When the purple wire in this picture is unplugged it has voltage to the prong on this device. When I plug it back in there is no voltage on the back side or purple wire. IDK what this is. Might be the pulse module? Or the EA/CC/SC? What ever they are. Is seems to loose the voltage almost like its protecting the circuit when I plug it in by not sending voltage.

 

[87manche]

you're saying you lose 12V on that big violet wire?

where's it go? That's a big fat conductor, so I'd assume it's to something the draws a good bit of power.

 

[Ghost]

you're saying you lose 12V on that big violet wire?

where's it go? That's a big fat conductor, so I'd assume it's to something the draws a good bit of power.

Well when I un plug it that box sends voltage to the pin. When I plug it in the box doesn't send voltage. And yea its a big wire. Like I said it's almost as if that wire is grounding and that box is protecting the ground. IDK where it goes. I guess I'll trace it tomorrow. I'd really like to know what that box is.

 

[87manche]

voltage where it's not supposed to be could also be a ground issue. You've checked those right? First place ot start.

 

[Ghost]

voltage where it's not supposed to be could also be a ground issue. You've checked those right? First place ot start.

All the grounds I checked looked good. I pulled the main ground near the pulse module where the purple wire lost voltage if it was plugged in and it was like new. Pulled the connector off the NSS and the purple wire under hood regained voltage. I need to get a pin diagram of the NSS.

 

[IllianaXJ]

Ignition switch?

 

[Ghost]

Ignition switch?

No if any part of the circuit up to and including the starter solenoid are removed they turn on the test light. I'm hoping to get someone to hit the key for me so I can put a volt meter on it and see if its losing voltage or if its just dead. I confirmed voltage at the starter solenoid. As in weather or not its 12v or less. I also need to confirm that voltage is going to the solenoid with the wire hooked up. That will have to happen when I get a key turner. I'm wondering is its not just a faulty solenoid on the starter.

 

[southernrebel20]

So, the starter solenoid fires when you stick a screwdriver in between the incoming post (battery lead) and the out going post (starter lead)? That doesn't mean the solenoid is working since you are just using the screwdriver to connect battery directly to the starter. The solenoid should have a trigger wire and either be externally or internally grounded. The trigger wire and ground are what operate the solenoid to make the connection between your battery and starter. Make sure you are getting 12v to the trigger wire when your key is in the start position, and that the solenoid is sufficiently grounded.

 

[Ghost]

So, the starter solenoid fires when you stick a screwdriver in between the incoming post (battery lead) and the out going post (starter lead)? That doesn't mean the solenoid is working since you are just using the screwdriver to connect battery directly to the starter. The solenoid should have a trigger wire and either be externally or internally grounded. The trigger wire and ground are what operate the solenoid to make the connection between your battery and starter. Make sure you are getting 12v to the trigger wire when your key is in the start position, and that the solenoid is sufficiently grounded.

No I am jumping 12v off the incoming lead to the jumper lead therefore starting it as if I was running 12v straight to the solenoid. I have confirmed with a test light that voltage is going to the solenoid wire from the ignition circuit.

 

[87manche]

I'm wondering is its not just a faulty solenoid on the starter.

works perfect when it works.


sounds like every bad starter solenoid I've ever had.

:illegalflipoff:

 

[Ghost]

I guess that is your way of saying replace the starter.......

 

[87manche]

I'd probably just replace/rebuild/clean your solenoid.

it's not hard.

looks like the fun part is getting it out

http://www.pelicanparts.com/techart...r_Replacement/39-ELEC-Starter_Replacement.htm

 

[md21722]

From reading the thread, I'm not clear if the solenoid wire is jumped if the starter always engages? If yes, I would look at the ignition switch and neutral safety switch. If no, I would look at the starter.

 

[Ghost]

From reading the thread, I'm not clear if the solenoid wire is jumped if the starter always engages? If yes, I would look at the ignition switch and neutral safety switch. If no, I would look at the starter.

Yes that is what I was thinking too. But, even when it's not starting I can jump it and the last time it happened it had voltage at the solenoid with the wire detached. I was thinking I'd check it for voltage as in how much was there and then reattach it and check and see if its still there and how much.
However, it has worked every time sense I pulled all the electrical connections and checked voltage at each. One thing I have noticed is how amazing clean all of the grounds and connections I have looked at.