M103 Engine Flooding Itself (1988 300E) - Page 2 - PeachParts Mercedes-Benz Forum

TechGuru · #16 03-18-2012, 11:12 PM

Quote:

Originally Posted by lorainfurniture

Have you checked to see if you are getting a good spark? I saw the video, and it sounds like it is firing randomly.

It's really hard to get these cars to actually not start. If you have no or weak spark, it can be cps,ezl, coil, wires, or plugs.

I cannot think of any scenario that would cause the spark to be out of time.. I don't think it is possible.

Fuel, spark, compression. The timing chain would be spot on, or busted..

First, I should let everyone know, the coil and spark plug wires were replaced about 4 months ago (Bosch OEM).

I have checked spark at the coil, very good blue spark, consistant.

I then checked the spark at a spark plug wire, of course it's only going to spark 1/6th as much as at the coil while cranking, it looked more gold and random.

The only way I can think of that the spark would make it to the wrong cyl is if the dist cap has a serious internal problem. It's out and I'm measuring resistance values on it now but I have no idea what they're supposed to be. The cap and rotor are 1 year 4 months old. BWD brand.

Spark plugs are about 2 years old, Denso non-resistor. I'd replace them now but I have to order them.

TechGuru · #17 03-19-2012, 02:14 AM

Anyone think the distro cap is bad?

http://www.youtube.com/watch?v=_sdAtR8qXiU

That's only 7kv jumping around, I think a ignition coil is far more.

116fan · #18 03-19-2012, 09:37 AM

I think yr distributor cap could be bad.
Replaced that and rotor 2 mnths ago on our '91 300 E due to non-starting when cold.
It solved the problem 100%.
Try it.

nulu · #19 03-19-2012, 09:07 PM

After watching your no start video , i agree sounds like spark going to wrong cylinders =change that cap,also look at rotor they like to burn thru backside and ground out telltale black trace marks

glpro160 · #20 03-20-2012, 12:24 AM

I'm pretty sure that the rotor is bad. Have a good look then you will see there's sign of leak at the rotor. Due to the leak the spark just can't get to the spark plugs.

TechGuru · #21 03-20-2012, 12:54 AM

Well, they are both under LTT, they won't be in at OReilly's until Wednesday.

TechGuru · #22 03-21-2012, 04:37 PM

Looks like the distro cap was the problem.

lorainfurniture · #23 03-21-2012, 04:47 PM

Quote:

Originally Posted by TechGuru

Looks like the distro cap was the problem.

Engine running fine?

TechGuru · #24 03-22-2012, 01:52 AM

Quote:

Originally Posted by lorainfurniture

Engine running fine?

Yep, drove it to town today, just a occasional mis at idle, probably could use new spark plugs. They're about 2 years old.

Cheap enough.

rickkhall · #25 04-02-2012, 02:42 PM

Quit buying junk parts. That engine calls for Bosch H9DCO copper plugs. at the dealer they are $2.35 each, less at other online parts stores. Buy what is required. A Bosch distributor cap and rotor may cost a little more but will last longer with no problems.

Adler · #26 04-03-2012, 01:59 PM

The 'pool of fuel at the bottom' could possibly indicate a leaking plunger seal or o-ring.
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TechGuru · #27 04-05-2012, 05:24 AM

Quote:

Originally Posted by rickkhall

Quit buying junk parts. That engine calls for Bosch H9DCO copper plugs. at the dealer they are $2.35 each, less at other online parts stores. Buy what is required. A Bosch distributor cap and rotor may cost a little more but will last longer with no problems.

The spark plugs the engine calls for are no longer made.

The current non-resistor options are Denso T20EP-U or Bosch F8DC4, I hear there is a NGK option too, but I don't have the PN on hand.

stormyc88 · #28 04-05-2012, 05:05 PM

They are no longer made, but they can still be purchased. I buy them at peachparts, at this link:
SPECIAL ORDER BOSCH H9DCO, these are "NOT" resistor spark plugs ''ONLY AVAILABLE WHILE STOCK LASTS'',0031590403 - PeachParts

They are currently $4.90 each.