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2005 CLK500 w/30K
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I had a '93 400e for several years. The caps/rotors failed a couple times. More than once I opened them up and found moisture inside. Word thing is I live in SoCal. No rain and no humidity. How they managed to collect water was a mystery I never solved.

But if that doesn't fix it, prepare to face the wiring harness monster.
 

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W124
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I was off base saying the caps should not have water in them. Of course they will develop moisture. The important thing is that the components are in good enough shape to operate with that moisture in there. The most important of all is those dust shields (insulators) as everyone has discussed here and on the 500e board. But moisture WILL happen because the caps are not sealed and should not be sealed. The correct caps for an M119 have six grooves in them which enable cool air to get pulled into a hot distributor thereby creating moisture. I suspect those grooves are there to allow gasses such as Ozone to vent out rather than be trapped within.
IMG_6292.JPG
 

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W124
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If the insulators are bad won't there be ignition voltage issues at the cylinders? I've replaced the caps and rotors probably 5 times over the life of the car and this stumble seems different from a caps/ignition failure. When running the engine shows steady 28 - 31V per cylinder which seems normal. I'll look at the insulator caps today. Thanks!
It depends on what you call ignition voltage issues. When an insulator fails, the EZL enables a spark pulse, the coil fires it, the coil wire transmits it, the cap transfers it to the rotor but at that point all bets are off. The spark jumps to the right cylinder, the wrong cylinder and not cylinder at all, over and over again. The ignition fired a healthy spark, it just didn't end up where it should have. I don't think a diagnostic module can help with this.
 

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1998 SL500 Sport
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7 Posts
Discussion Starter #24
It depends on what you call ignition voltage issues. When an insulator fails, the EZL enables a spark pulse, the coil fires it, the coil wire transmits it, the cap transfers it to the rotor but at that point all bets are off. The spark jumps to the right cylinder, the wrong cylinder and not cylinder at all, over and over again. The ignition fired a healthy spark, it just didn't end up where it should have. I don't think a diagnostic module can help with this.
When the car is running, the live data below is what I pulled from Xentry. I thought this might indicate proper firing of the ignition system? The question would be where the voltage readings are being pulled from. (I have new insulators on order now.)

2622834
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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On the other hand, I have seen that for BMW's at least you can sometimes buy OEM parts that are exactly the same as Original BMW parts for a much lower price also. For instance, I once bought some TRW branded M3 control arms where the "M3" logo was just ground off the metal so they could sell it that way at lower cost ....
This is true, but you're expecting OEM suppliers to make the original parts JUST as they did when they were supplying MB. And it just isn't so in a lot of cases. It's almost like an honor sytem and we know how honor systems work.

Bosch is one of the worst offenders for this and seem to have different 'levels' that no one truly understands. An example would be the 103 dist. You can get it from most places for $50/Bosch, made in Spain....but the same Spanish made dealer cap is over $200. Some say the dealer caps get a special coating. How about we find out what the secret sauce is and coat the $50 caps ourselves....lol.

Point being, don't blindly trust OEM to be exactly the quality that OE parts were/are.

Kevin
 

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1977 W123.123 1995 W124.034
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This is true, but you're expecting OEM suppliers to make the original parts JUST as they did when they were supplying MB. And it just isn't so in a lot of cases. It's almost like an honor sytem and we know how honor systems work.

Bosch is one of the worst offenders for this and seem to have different 'levels' that no one truly understands. An example would be the 103 dist. You can get it from most places for $50/Bosch, made in Spain....but the same Spanish made dealer cap is over $200. Some say the dealer caps get a special coating. How about we find out what the secret sauce is and coat the $50 caps ourselves....lol.

Point being, don't blindly trust OEM to be exactly the quality that OE parts were/are.

Kevin
Bosch caps, rotors and insulators for the M119 are still of pretty good quality.
 

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1998 SL500 Sport
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7 Posts
Discussion Starter #27
New insulator caps and no change. The car idles rough but isn't "missing" or "stumbling" per say, just sounds like shit and has a constant vibration.
 

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W124
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In your first post you mentioned smelling a rich mixture. Is that still a problem? Does the car still feel like its down one or two cylinders as you mentioned? The mention of a vibration seems new - have you ruled out engine mounts?
 

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1995 E-420
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67 Posts
I just had my distributor caps and rotors replaced to get a newly purchased car running properly. The shop said when they pulled the old ones, the housings were filled with water so they put silicone on the new ones to try and prevent this. I also noticed after I bought the car that this was the second time in a year or two that the distributors had been replaced. I doubt the shop went as far as replacing these insulators you are talking about so I was thinking about possibly doing this soon to protect the new distributors but I looked up the parts diagram and don't see any "insulators" that you are talking about here M 119.975 - IGNITION SYSTEM > Mercedes EPC Online > nemigaparts.com
How would I go about ordering these and where are they located exactly?
I'm running Bremi Caps and Rotors with Bosh insulators all bought from FCP Euro. Trying to seal the caps would be a really bad idea and will cause all kinds of issues. A deteriorating set of the insulators will manufacture a weird jell that is not water but will play havoc with the ignition in these cars. Been driving a 95 E 420 almost daily for almost 8 years now fought this fight before.
Try here
 

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1995 E320 Cabriolet
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Wow, the Bosch branded distributor is $85.49 compared to $216.20 for Genuine Mercedes........I hear you though that some "OEM" parts are not the same quality as genuine....
I would be tempted to go with the Bosch. Maybe I’m lucky but I’ve never had a non-OEM part prematurely fail.
 

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I'm running Bremi Caps and Rotors with Bosh insulators all bought from FCP Euro. Trying to seal the caps would be a really bad idea and will cause all kinds of issues. A deteriorating set of the insulators will manufacture a weird jell that is not water but will play havoc with the ignition in these cars. Been driving a 95 E 420 almost daily for almost 8 years now fought this fight before.
Try here
Dang maybe I need to have a look at my distributors to see exactly what this shop did, they told me they "sealed them up with silicone" to keep out condensation...
 
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