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 05-15-2004, 02:13 PM
haasman's Avatar
Registered User
 
Join Date: Jun 2001
Location: San Francisco, CA
Posts: 3,097
Stupid spark plug wire question ...

I got shocked (not too bad) when adjusting the timing on one of the cars by my hand touching one of the plug wires that goes into the distributor cap.

My question: Is this perfectly normal (considering the amount of hight voltage) or does this indicate that wire is bad?

.... and no, I won't test the other plug wires this way!

Haasman

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
Reply With Quote
  #2  
Old 05-15-2004, 02:24 PM
Moderator
 
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
It is pretty normal. In theory it probably shouldn't happen. It hapens more often if the voltage necessary for firing the plug is higher.

It would be likely that the insulation should take 30kv or more. A plug normally has enough resistance in its gap and all the resistors in the wiring to cause the firing voltage to be 10kv or so.

A wore out plug with a very large gap or an open circuited plug end resistor might cause the firing voltage to approach the end of the coils capability at 30kv. if you pull a plug wire and hold it away from the engine the open circuit voltage goes to available voltage, around 30kv.

If at anytime a lower resistance path to ground appears that becomes the new path. When holding the disconnected plug wire it is often common for sparks to jump from the center coil terminal to the ground of the coil/controller (one reason it not good to open circuit secondary wiring).

So if it jumped to you, then the insulation is weaker than the available voltage and you were closer than the plug in voltage potential.
__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician
Reply With Quote
  #3  
Old 05-15-2004, 02:27 PM
haasman's Avatar
Registered User
 
Join Date: Jun 2001
Location: San Francisco, CA
Posts: 3,097
Steve

As usual, great answer.

Thanks,

Haasman

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
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 03:07 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, 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