M104.980 won't start... i need suggestions before sending it to the crusher

Dec 10, 2010 | 05:30 PM

fredtga

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Joined: Aug 2007

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From: Los Angeles, CA

w202

M104.980 won't start... i need suggestions before sending it to the crusher

Yes, the black sheep of the M104 engines... i have the 3.0 24V engine that came on the 300CE, everything is new: sparkplugs, wires, rotor and distributor cap, coil, OVP, i measured the values of the crank sensor and such... everything falls between the correct values.
Engine cranks, tacho bounces in the dash, but won't start for the life of it...

There is gas since i smell it, i even took out the plugs and left it overnight in case it was flooded.

One issue: i put an inline spark tester and the spark is orange color not the bright blue... so i think it's gotta be an ignition problem.

Questions and I need opinions what to do:

1. I just want to hear it start before doing any other work on it, so i'm trying to start the engine without the belt in place in with no water in the system, just oil. I'm asking: would this be an issue for the engine not to start? I don't think, but i'm asking all the stupid questions since i'm out of ideas.

2. How can I test the EZL? how can i make sure it's working?

3. I just want to hear it start, or at least to try to start, sputter, i don't need it to idle... what components are in play for starting this engine?
Engine harness was redone... could something go wrong? what harness components should i test?

thanks for the help... i'll give it till the end of the year, after that i'm ripping it apart

Dec 11, 2010 | 11:55 AM

bsmuwk

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Joined: Jun 2008

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From: IL / WI

Depends on the day

i think you need the alternator going for the engine to run. with all the cranking the battery doesn't have enough juice left in it for some ignition action. i guess you could run the engine for a few seconds, but the engine really needs the steady charge from the alternator. you dont need water if you're going to run it for a few seconds, just put the belt back on for now and give it a whirl. try starting it with some ether for an extra boost and if it won't run with a little ether in it, chances are that ezl might have gone kaput.

the only way i know how to test the ezl is to swap it with a working one....unfortunately.

Last edited by bsmuwk; Dec 11, 2010 at 11:58 AM.

Dec 11, 2010 | 05:42 PM

fredtga

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From: Los Angeles, CA

w202

i have the car hooked up to one of those external starter/battery charger box so there is power, engine cranks fine, i can smell gas, but cranks over and over without even trying to start...

as i said, i'm getting a weak spark... should there even be a spark if the EZL is gone?

i'm waiting for several EZLs to come in from Europe, i'll give it a try with one of those...

Dec 12, 2010 | 11:11 AM

bsmuwk

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Joined: Jun 2008

Posts: 281

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From: IL / WI

Depends on the day

Quote:

Originally Posted by fredtga

Let's just get the simple stuff out of the way..
How positive are you that the plug wires are all connected the right way?
Check to see if you're getting 12+ volts at the battery and 10+ volts at the coil.
I'm assuming you're using non resistor spark plugs, right? Wires already have resistance built into them, resistor plugs just give off a weaker spark. .

You're getting fuel, that's good. You have all the basics down, just go through them again.

Last edited by bsmuwk; Dec 12, 2010 at 11:25 AM.

Dec 25, 2010 | 12:39 PM

JAWMERC

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Joined: Dec 2010

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1982 MB 300SD, 1988 MB 300E, 2001 Ford Taurus SES, 2005 Dodge Dakota SLT

I don't mean to try to insult you or anything but I had a very similar with my 103 (I know they are different engines). Before replacing the head gasket it started right up but when I had it planed and put it back on and hooked everything up it would not start. I liked to crank over and over but nothing. I tried ether it just ran off the fumes, I replaced the fuel distributor and fuel pumps and injectors, distributor, and rotor. It still would not start even though I smelled gas, I nearly gave up until I realized that I was over looking the basics...vacuum. My hose from the valve cover to the air filter was missing, but when I stuck my finger over the valve cover it would start right up and stay on, when I took my finger off it just shut off immediately. Not sure if that helps any because you have a 104, but just some food for thought.

Dec 25, 2010 | 07:58 PM

fredtga

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Joined: Aug 2007

Posts: 344

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From: Los Angeles, CA

w202

no worries, i'm open to any ideas, that's why i posted here...
i put back also the air filter housing to have everything plugged in, but still, the car does not want to start...
i have some spare parts to test with, but they're all stuck in europe... there's something going on again with air post and you can't send to US larger package than 400g...

if it won't sell this week, prolly EFI will be on its way onto this engine...