Starting problem
Just cross posting into this thread because @ignorant had asked me to post here as well.
https://mbworld.org/forums/gl-class-...ml#post7595309
Hopefully one of us here can figure this issue out and get it nipped in the *** without pouring tons of money and time into things that don't work.
Just a refresh form my post:
Just got the truck the other day, took care of an oil leak that turned out to jut be a missing o-ring on the oil filler cap.
It leaked oil all over the exhaust manifold, alternator, and who knows where else down the side of the motor.
Cleaned it up as best as I could but this issue could very well be the cable linked in this thread.
Things I have tested so far:
Fuel pressure at the rail (52-60psi)
New BOSCH glass pack battery 1000 cranking amps
Ordered a new crankshaft position sensor (waiting for it to be delivered) but if this isn't needed I would rather not waste the time replacing it.
But if everyone suspects its the cable going form the alternator to the starter I might want to try that next. Has anyone run a test on the cable to make sure its pulling the correct amperage?
Last edited by Aboshi; Nov 5, 2018 at 02:54 PM.

I am definitely going to have to do this within the next week or so because trying to start the car today after a short trip it turned over very slow, paused and cranked again a few more times before giving up completely. I had to switch the car off and try again, and it started instantly. So I really hope it's just the positive lead cable. If there was more room at the starter I'd just hook up a meter and check the amperage
Im still having starting issue intermittently.
Working on a couple things will update if it solve the problem




Does it sometimes take less tries?
Any consistent theme? ( How long it sat, temperature, etc.?)
Does it crank at a normal speed?
Do you have a OBD tester with a start test feature?
Did you change out the positive lead cable to the starter?
Hopefully you narrow it down, I still haven't had time to change out the positive lead cable to test that theory yet

@N_Jay
For me its random, sometimes it will start the first crank, sometimes it will crank for at least 10 seconds, maybe a little less maybe a little more. So its totally random.
I highly doubt its the starter or by now it would have died by now. I also doubt its a fuel pressure issue because the starter just stops craning for a second before cranking hard again.
I guess I personally wont know until I change out this lead cable already. I just haven't even had time too see how involved of a process its going to be. I really hope its easy enough to just get my hand by the starter positive side without having to remove the exhaust.
The Best of Mercedes & AMG








A) Its not super expensive, probably a few hundred bucks more expensive than what you've paid for the relays.
B) Probably would solve your problem.
Please keep us updated on how you proceed. (The positive cable is 90 bucks or around that)
* When it doesn't start... it can take up to 15 crank tries before it starts.
* I haven't changed out the cable which runs from the Jumper terminal junction box to the alternator then to starter. It is one cable that jumps the 3 locations.
I was concern with running my battery dead. One strange thing I did notice was when I connect a battery charger to the jumper terminal it started. I'm working this angle right now. Possible Jumper terminal box issue. Will keep you all posted.
I highly doubt its the starter or by now it would have died by now. I also doubt its a fuel pressure issue because the starter just stops craning for a second before cranking hard again.
I had a 2011 C300 I bought brand new and the starter went out on me 4 months later! It wasn't a gradual thing. One day it would work perfect and the next it wouldn't, after 3 days of that the starter was fully dead and wouldn't even move. The issue with what were all having seems more insidious than a failing starter. Plus I don't like throwing $ at a problem, because if its not the starter that's a hell of lot of labor on a whim. I know I can change it myself but it's too cold in the north east now. Shops charge $129-179 an hour here and there's no way I'm parting with over $1000+ to change a starter especially when its not a guaranteed silver bullet.
It caused me tremendous grief because it endlessly seemed like it was something else. Fuel starvation, weak battery, etc. Compounding the problem is that it leads to excessive battery draining. Even my indy mechanic didn't diagnose it. First they said nothing was wrong, then they seemed a little puzzled when I showed how it was sluggish. I guess I'm pretty sensitive, because I suddenly noticed it cranking slower one day, and it steadily degraded from there.
Looking at your symptoms again, it sure does seem like the starter is at fault. Sudden sluggishness followed by intermittent degradation.
Check out Mercedes Medic for tips on changing the starter without removing the exhaust.
Last edited by eric_in_sd; Dec 6, 2018 at 02:27 PM.

Guess I will have to get some heaters out in the driveway and do the remove the engine mount method ;(
I guess I wont have a choice but to try the starter first.
Thanks for the insight
so far I replaced battery, MAF sensor, sparkplugs. I replaced the Jumper junction box 2x100amp and 1x 40amp prefuses. My Indy replaced the Crank position sensor. Nothing helps. Its getting worse. But Now I get more of a consistency of after driving. I have to wait 5 hours before it will start. My indy didn,t think it is the starter because it cranks fine.
My Indy is thinking it is the engine ECU. which is a dealer part at about $2000.
I dont want to keep throwing in money to try - harness and starter.
This thing is falling apart after being 10 years old. Frustrated!!!!!
You had to try the positive cable harness first.
This is not my opinion, it is the combined experience of this forum.
I will "try" that one first even though it costs 500-1000 dollars, that would still be my first bet.
I don't want to live with my disappointments after each "cheaper and worth-a-shot" fix effort.
The replacement part is 100 bucks, can you get a quote on labor for that part from your mechanic? Maybe it's not that expensive at the end.
You indy owes you a favor now, right?
My indy didn't recognize the weak starter either. It cranked at a reasonable speed, but I think the ECU avoids fuel delivery when the rotation isn't fast enough. Changed to a new starter and it jumps to life basically instantaneously.




so far I replaced battery, MAF sensor, sparkplugs. I replaced the Jumper junction box 2x100amp and 1x 40amp prefuses. My Indy replaced the Crank position sensor. Nothing helps. Its getting worse. But Now I get more of a consistency of after driving. I have to wait 5 hours before it will start. My indy didn,t think it is the starter because it cranks fine.
My Indy is thinking it is the engine ECU. which is a dealer part at about $2000.
I dont want to keep throwing in money to try - harness and starter.
This thing is falling apart after being 10 years old. Frustrated!!!!!







