95 S600 Coupe failed emissions - Page 2 - PeachParts Mercedes-Benz Forum

Hatebreed · #16 11-15-2018, 05:40 AM

Quote:

Originally Posted by anziani

hatebreed, definitely take a hard look at a Star system or pay your dealer to scan your engine. Most decent indies also have the Star scanner.
I bought my '97 CL600 a couple of years ago. It is the finest and last car I will ever own. And you're right about the speed and power. I had mine up to 145MPH and it was barely breathing hard! And I've had little if any problems outside normal maintenance items. Did I understand you right in that you have no CE light? or has it been disconnected? These are very complex cars and I would suggest you find a GOOD indie to help you.
Anziani
'97 CL600 68K

The light works. This is my only hobby, so figuring things out is kind of the fun part for me...LOL

Hatebreed · #17 11-27-2018, 06:01 AM

UPDATE: I have completed the following to correct the RH Bank too rich condition:

1. Inspection of the MAF sensor wiring: Good
2. Swap of the MAF sensors - Condition remained
3. Swap of the O2 Sensors - Condition Remained
4. No codes present
5. Inspection of the RH Ignition - Failed
a. Found Center electrode missing from Cap- found underneath the assembly
- Inspection of the cap found burns at center point and a crack
- Inspection of the rotor found no indication that center pin was installed
- LH Cap was removed for comparison and clear indications on the rotor that it
riding on the center pin. This was not the case for the RH side.

5. I have the cap reinstalled with the pin in the center - Seems to run better with less smoke. My guess is that I will need to burn off the coking and crap that has been running through the exhaust system. Once the engine is cooled, I will remove the plugs and clean.

Question: Is the center pin supposed to be able to be removed? My guess is no, as this would serve little purpose and only lead to issues during installation. Any input would be appreciated...

Thank you!!

MAVA · #18 12-07-2018, 04:24 PM

On these early to mid 90's m120's with distributor caps. The combustion is critical, and the two cheap sensors responsible for this are those four-wire temperature sensors on the thermostat pipe. It is the same sensor on a M119 as it only has one..

Change both, and I think you will solve your problem providing your MAF wiring is good.

Ohh by the way MB Star will say it is the MAF sensors which is dead wrong. I'm old school, and you do not need star for these distributor engines...

Martin

jhodg5ck · #19 12-08-2018, 08:10 AM

Quote:

Originally Posted by MAVA

On these early to mid 90's m120's with distributor caps. The combustion is critical, and the two cheap sensors responsible for this are those four-wire temperature sensors on the thermostat pipe. It is the same sensor on a M119 as it only has one..

Change both, and I think you will solve your problem providing your MAF wiring is good.

Ohh by the way MB Star will say it is the MAF sensors which is dead wrong. I'm old school, and you do not need star for these distributor engines...

Martin

Early 140's don't need SDS? I appreciate the notion but in reality the problems them come in with now... You would invest ungodly amounts of time chasing things.

Just for kicks, how's he gonna diagnose when the neutral safety switch is killing CAN and putting the engine into LHM? The list goes On and On.

Jono

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anziani · #20 12-11-2018, 11:53 AM

Have you replaced the fuel regulator? When I got my CL600, the idle was wandering. A new regulator fixed it.
Anziani

Hatebreed · #21 01-24-2019, 07:11 AM

Quote:

Originally Posted by anziani

Have you replaced the fuel regulator? When I got my CL600, the idle was wandering. A new regulator fixed it.
Anziani

Hello, Yes the final fix for this issue was the fuel pressure regulator. The regulator diaphragm had failed and fuel was being drawn into the intake manifold through the vacuum line. The FPR takes vacuum from the left side of the manifold and feeds the right side bank of cylinders. This is why I was getting fouled plugs on the right hand side. The un-metered fuel was creating a surge condition due to being combined with normal intake air. The #6 cylinder being the closest to the vacuum/fuel source was considerably more fouled that the #1. Car runs perfect now. I managed to not spend too much money on unnecessary replacements through use of this site and simple troubleshooting.

Thank you to everyone who commented. Much to my wife's disappointment I may keep this car. Its an absolute blast to drive. I still have my trusty 300SDL as back up....LOL. All said and done, I have less than $1,500 into a mint condition 1995 S600 with 88K on the clock. .

jhodg5ck · #22 01-24-2019, 07:49 AM

Quote:

Originally Posted by Hatebreed

Hello, Yes the final fix for this issue was the fuel pressure regulator. The regulator diaphragm had failed and fuel was being drawn into the intake manifold through the vacuum line. The FPR takes vacuum from the left side of the manifold and feeds the right side bank of cylinders. This is why I was getting fouled plugs on the right hand side. The un-metered fuel was creating a surge condition due to being combined with normal intake air. The #6 cylinder being the closest to the vacuum/fuel source was considerably more fouled that the #1. Car runs perfect now. I managed to not spend too much money on unnecessary replacements through use of this site and simple troubleshooting.

Thank you to everyone who commented. Much to my wife's disappointment I may keep this car. Its an absolute blast to drive. I still have my trusty 300SDL as back up....LOL. All said and done, I have less than $1,500 into a mint condition 1995 S600 with 88K on the clock. .

Congratulations! There will be More...

@ that mileage I would try to get to a Benz Indy shop so they can get her on a rack/inspect Everything underneath. You're getting close to needing steering and suspension bits.
If accumulators haven't been done plan on that. They are a 10 year 100k mile kind of part.

Upper control arms, lower bushings, ball joints, engine mounts....it's all about that time mileage wise and Well past on time.

Enjoy your m120 though...when they're Right they're awesome

Jono

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