Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 03-24-2006, 12:40 PM
Registered User
 
Join Date: Mar 2006
Location: Seattle, WA
Posts: 33
Unhappy '95 E320 wagon misfire

Hey tech gurus!
So after 15 years of Volvos (my last 940 Turbo wagon was totalled last month), I recently bought a pristine E320 wagon with 63k miles on it, and 90% of the time the engine is like butter (3.2 liter in-line 6). The problem is, I have an intermittent misfire and really don't know where to start looking. A couple things I've noticed, which may or may not be connected...
1) It doesn't seem to happen when the car is cold.
2) There is definite interference with the AM radio signal. (i.e. when I hit the gas, the static noise gets louder and speeds up in relation to the rpms the engine is pulling.)
I took it to the dealer I bought it from and they thought it was related to an oil-flooded spark-plug socket (where the lead goes in, not in the cylinder), so they replaced the valve cover gaskets. It seemed to help for a day or so, but that's probably my imagination. I'm relatively certain that it's an ignition problem.
My thought is that I possibly have bad spark plug leads (does this mean I need to change out the coil packs?) I'm going to put some injector cleaner and dry gas in it today, on the off chance that it's just water in the gas.
For what it's worth the engine wiring harness was replaced in the last year or so, according to the paperwork that came with the car.
I'm a fairly adept mechanic, having restored a '64 Volvo, and maintained my own 240s and 940 for years and can do the actual work, but as far as diagnosing problems, some of this Mercedes stuff is still a little over my head. (I did buy the Bentley E320 owner's guide, and am working my way through it.) Thanks in advance for your help!
-Ethan H.

Reply With Quote
  #2  
Old 03-24-2006, 12:47 PM
Registered User
 
Join Date: Mar 2006
Location: Seattle, WA
Posts: 33
Oh, I should also mention that it cruises along just fine on the freeway (sometimes stumbles on hard acceleration, but not every time), idles beautifully (usually the stumble kicks in around 2000rpm), generally accelerates up to 2000 rpm very smoothly, and hot and cold starts are both fine. Any ideas?
--Ethan H.
Reply With Quote
  #3  
Old 03-24-2006, 12:51 PM
Registered User
 
Join Date: Mar 2006
Location: Seattle, WA
Posts: 33
Oh, and the check engine light isn't on. Right, I think that covers it....
-_Ethan
Reply With Quote
  #4  
Old 03-24-2006, 01:02 PM
Moderator
 
Join Date: Dec 2001
Location: Southern California, U.S.A.
Posts: 8,538
99% of misfires on M104 engines are due to bad coil wire supressor boots.

Change all three of them. They are cheap.

Also, it is critical that you are running original Bosch or Beru copper core non-resistor plugs.

The plugs must be the non-resistor type.
__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".
Reply With Quote
  #5  
Old 03-24-2006, 01:28 PM
Registered User
 
Join Date: May 2003
Location: DC Metro Area
Posts: 365
Not sure what the change interval is on the rotor and cap for the ignition, but this would explain the hot-only problem and AM interference.

Probably due for a change anyway at 60k.

Good luck,
Troy
1995 E420 107k
Reply With Quote
  #6  
Old 03-24-2006, 01:44 PM
Registered User
 
Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,804
Quote:
Originally Posted by y2kimmel
Not sure what the change interval is on the rotor and cap for the ignition, but this would explain the hot-only problem and AM interference.

Probably due for a change anyway at 60k.

Good luck,
Troy
1995 E420 107k
Unlike your E420, that chassis has DIS ignition.....
Reply With Quote
  #7  
Old 03-27-2006, 10:44 AM
Registered User
 
Join Date: Mar 2006
Location: Seattle, WA
Posts: 33
Thumbs up

Okay, so I changed the coil wire suppressor boots out and installed new spark plugs, and it seems to have done the trick. The old plugs were definitely shot (gaps were around 1.10 mm), and the boots looked like they were probably the originals. Thanks for the help!
-Ethan
Reply With Quote
  #8  
Old 03-27-2006, 10:53 AM
Registered User
 
Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,804
What did you use for plugs??
Reply With Quote
  #9  
Old 03-27-2006, 11:35 AM
Registered User
 
Join Date: Mar 2006
Location: Seattle, WA
Posts: 33
Quote:
Originally Posted by Arthur Dalton
What did you use for plugs??
Copper core Bosch non-resistor type. I'm not sure what the designation was off-hand, but they were the ones that the dealer recommended and were the same as the old ones (which I suspect were the originals from the factory.) The car only has 63k on it....
--Ethan
Reply With Quote
  #10  
Old 03-27-2006, 12:15 PM
Registered User
 
Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,804
Very Good

The # Is F8DC4, for future reference.

I only ask b/c some auto parts houses are known for giving out R plugs or Plats for this car, and the 104 just does't like them. [ Waste spark system]

Many of the discount parts counter guys came from "want Fries with that ? "...if you know what I mean...
Reply With Quote
  #11  
Old 03-27-2006, 12:37 PM
Registered User
 
Join Date: Mar 2006
Location: Seattle, WA
Posts: 33
Quote:
Originally Posted by Arthur Dalton
The # Is F8DC4, for future reference.
That was the one.


--Ethan
Reply With Quote
  #12  
Old 03-29-2007, 07:05 PM
Registered User
 
Join Date: May 2003
Location: Atlanta
Posts: 398
sorry but what exactly is a "coil wire suppressor boot"

I dont see anything with that name on fastlane. I'm assuming is not the same as an "ignition coil"


my 95 e320 wagon (118k) suddenly has a horribly rough idle and loss of power under light acceleration. hasn't stalled and isn't throwing codes. I'm also looking into the O2 sensor, and various vac connections (but all look okay). any other ideas?
Reply With Quote
  #13  
Old 03-29-2007, 07:47 PM
Sportlines
 
Join Date: Oct 2004
Location: Johnson City, TN
Posts: 985
Referred to as Spark Plug Connector

Steve
Reply With Quote
  #14  
Old 03-30-2007, 12:23 PM
Moderator
 
Join Date: Dec 2001
Location: Southern California, U.S.A.
Posts: 8,538
http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=21Q1AKMTB21U0QIXGA&year=1995&make=MB&model=E-320-004&category=F&part=Ignition+Wire+End+Plug
__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".
Reply With Quote
  #15  
Old 03-30-2007, 01:38 PM
Registered User
 
Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,804
Plug connectors are a supressor resistor ..there are 3 are under the coils.
[ one each]
Plug wire boots are at the end of the ignition wires at the coil end of the wire and are just a wire terminal/plug with a protective boot over the terminal ..there are NO resistor/Supressors in this boot/plug.. The resistor connectors for those 3 ignition wires is at the other end of this ignition wire
[ plug end]
The 3 connectors under the coils have NO Ignition wires ..only a resistor /connector.
.. ..so, there are only 3 Ignition Wires on a 104 waste spark ignition system, but all plugs get the resistor/suppressor...either in the connector under the coil or at the plug end of an ignition wire.

So, why do we always recommend changing the connectors under the coils.??? B/C they have a high fail rate due to 2 factors ..one is the are trapped in engine and coil heat and the other is they have a friction type commpression spring connection to the plug by design. Two things resistors do not like are heat and poor connections.
The resistors on the other plugs do not have these condition b/c they are not heat trapped and they have positive snap design connector..so, very seldom will one see a failure on them, but you frequently see failure on the ones under the coils..so much so that any tech familiar with these will just change them automatically when doing a plug change...
... the high percentage of 104 misfires are caused by these coil over plug connectors, along with incorrect plugs installed , specially Plats... these engine like the large electrode of the copper core standard plug b/c they are a series circuit of two plugs fired with one coil...meaning the first plug fires from the electrode to ground , but the second plug, being a series circuit, fires from ground to the electode and then back to the coil..completeing the series circuit. Plat have a tiny electrode and that may contribute to their mis-fire rate in waste spark systems like the 104 has.


Last edited by Arthur Dalton; 03-30-2007 at 02:47 PM.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 04:28 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page