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Old 02-08-2004, 07:58 AM
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Join Date: Nov 2003
Location: philippines
Posts: 30
Learning experience: bad idle, black smoke, hesitation, stalling, lack of power

MB E320/300e 24 valve, 6 zyl 104(980) engine, CIS-E

My learning and costly experience might help other in the same predicament.

ive finally found the causes of intermittent bad idling sometimes near stalling at stop, hesitation after half hour driving, black smoke with lack of power, accumulation of black soot on exhaust
caused by incomplete combustion, black plugs which always gets fouled.

1. intermitent idling is caused by oil leaking into distributor from
bad O ring and front timing cover oil seal causing short circuits.

I suggest that before spending on a new cap and rotor (both being very durable), prioritize new plugs, high tension wires and
and oil leak. i thought that the warm hesitation and loss of power is due to bad coil but anyway, i would suggest changing the ignition coil.

2. i have look into the EHA current and even measured it and tried
driving it with and without EHA connected but just the same there is warm hesitation after 1 hr driving with black smoke and cant even drive into a high driveway and with EHA current within normal range

Problem: bad fuel filter.

After long drive, filter gets clogged causing probably low pressure
and the ECU compensates by richening fuel and causes fouling of plugs, black smoke and soot and my fuel consumption drops from
4-5km/l to 2-3km/l.

Savings: I dont have to change my harness which i
rewired with the help of an electrician.
MB tech. told me that rewiring is not compatible with MB

In Summary, i suggest changing all that i have mentioned
and probably you could include OVP. Also wash/clean your exhaust of all the black soot it has accumulated because of poor engine performance

I HAVE A NEW MODIFICATION TO IMPROVE RESPONSIVENESS (which i have accidentally discovered from my vw golf when i
revise its vacuum tubings with a pneumatic connectors)

Place a pneumatic connector on the tubing going into the EZL
AKR ignition system. ( can also be used for cars with mechanical advancer). This connector is a one way check valve which maintains a higher vacuum into the ignition causing the engine to be a little bit advanced in timing.
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Old 02-08-2004, 02:07 PM
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
"After long drive, filter gets clogged causing probably low pressure and the ECU compensates by richening fuel and causes fouling of plugs, black smoke and soot and my fuel consumption drops from 4-5km/l to 2-3km/l."

I view most of this post like the three blind men and the elephant. Each sensing a small part and drawing disasterously wrong conclusions on the whole. I'm going to leave it alone except for the above distinctly wrong evaluation.

In the above hypothesis it is claimed that the restricted fuel filter causes low pressure. I can buy that. It is then surmized that the controller will richen the mixture. I'll buy that attempt.

But the further assumption that this rich mixture fouls plugs totally misses the boat. First if the controller could control that much (which it can't) why would it take that very lean mixture through the normal mixture range to the radical rich situation that would foul plugs. Secondly and thirdly would get complicated, having to do with the concept of control when control is based on stable fuel pressure. Pretty hard to use mixture control where control is based on changing a pressure by about 3 psi when the system pressure is varying.

As for recommending system modifications by anyone not a master using full testing, I'm against it. By disabling the timing vacuum control you have no idea what you are doing. If you really wished to make a timing mod disabling the system wouldn't be the answer. The answer would be to use the provisions within the system for timing increase. That allows the system to do what its is supposed to when the pedal isn't to the metal. While full throttle might have more timing thinking it is idling, there are many times the timing would be higher if not idling. Unless you know whats supposed to happen it is not likely you are really outsmarting the system.

This post looks a lot like a little knowledge being a dangerous thing.
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician
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