New to Forum. Here's my son's '94 C280
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Joined: Apr 2016
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1994 C280
New to Forum. Here's my son's '94 C280
Not bad for a first car for an 18-year old.
Here's the skinny:
107,000 miles. Car is clean, tight and rust free. Had a wiring harness issue and the PO replaced it as well as the trans harness.
It does have some ignition issues and I'm not sure if it is more than I want to tackle. I work in a body shop and have access to a scanner. These are the codes:
Symptoms are rough, bouncy idle and rough acceleration that increases as the car warms up. Car rides smooth as glass with foot off the accelerator, but as soon as I give some gas, I get a vibration. Feels like a cylinder or 2 is not doing its job. It gets pretty bad after 1/2 hour drive and the power dies to almost zero, but turning off the ignition and restarting clears it up until it drives a while again.
Climate control baffles do not operate nor do the locks, so there is likely a vacuum issue. I'm not 100% sure the guy that replaced the harness did not knock something off. I do not have a smoker.
Anyone know of a good ole MB guy in central NJ?
Here's the skinny:
107,000 miles. Car is clean, tight and rust free. Had a wiring harness issue and the PO replaced it as well as the trans harness.
It does have some ignition issues and I'm not sure if it is more than I want to tackle. I work in a body shop and have access to a scanner. These are the codes:
Symptoms are rough, bouncy idle and rough acceleration that increases as the car warms up. Car rides smooth as glass with foot off the accelerator, but as soon as I give some gas, I get a vibration. Feels like a cylinder or 2 is not doing its job. It gets pretty bad after 1/2 hour drive and the power dies to almost zero, but turning off the ignition and restarting clears it up until it drives a while again.
Climate control baffles do not operate nor do the locks, so there is likely a vacuum issue. I'm not 100% sure the guy that replaced the harness did not knock something off. I do not have a smoker.
Anyone know of a good ole MB guy in central NJ?
Last edited by almico; Apr 11, 2016 at 03:20 PM.
Thread Starter
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Joined: Apr 2016
Posts: 10
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1994 C280
So I just read this over on Wiki and it sounds exactly like the issue I'm having:
<i>Whilst the M104 is known to be a reliable engine, there were some technical issues with smooth running. The wiring loom which passed from the Idle Speed Control unit (an electronic box situated in the engine bay) to the ignition coils (housed on the top of the engine) was enclosed under plastic covers. High temperatures were experienced in this region. In addition the plastic insulation was a type which degrades with time and heat.
The ignition coils provided current for two spark plugs each. A system of “Wasted spark” was used where one coil powers two spark plugs. But the coils were still subjected to a high heat zone.
Idle speed problems could be experienced if the coils / wiring breakdown damaged the Idle speed controller. This manifested itself with engine not idling at the correct rpm, normally 667, but hunting could be experienced with the engine ranging up to 1200 rpm. If the coils become damaged they may still operate at low engine rpm normally, but at higher engine loads the coils can break down resulting in engine power loss as the number of power producing cylinders reduce from six to four or even in worse case scenarios two.
Wiring loom upgrade kits were made available with upgraded insulation to resist the heat.</i>
<i>Whilst the M104 is known to be a reliable engine, there were some technical issues with smooth running. The wiring loom which passed from the Idle Speed Control unit (an electronic box situated in the engine bay) to the ignition coils (housed on the top of the engine) was enclosed under plastic covers. High temperatures were experienced in this region. In addition the plastic insulation was a type which degrades with time and heat.
The ignition coils provided current for two spark plugs each. A system of “Wasted spark” was used where one coil powers two spark plugs. But the coils were still subjected to a high heat zone.
Idle speed problems could be experienced if the coils / wiring breakdown damaged the Idle speed controller. This manifested itself with engine not idling at the correct rpm, normally 667, but hunting could be experienced with the engine ranging up to 1200 rpm. If the coils become damaged they may still operate at low engine rpm normally, but at higher engine loads the coils can break down resulting in engine power loss as the number of power producing cylinders reduce from six to four or even in worse case scenarios two.
Wiring loom upgrade kits were made available with upgraded insulation to resist the heat.</i>
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Joined: Apr 2015
Posts: 1,739
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From: London ON Canada
2012 C300 4Matic Sport Sedan
Hey welcome! if you haven't done this post in the W202 section you'll have better luck getting answers there.
Defiantly a nice ride for an 18 year old my first car was lets just say something special hahaha.
good luck and hope you find the answers your looking for
Defiantly a nice ride for an 18 year old my first car was lets just say something special hahaha.
good luck and hope you find the answers your looking for
