Parts Catalog Accessories Catalog Tech Info Tech Forums
  Search our site:    
 Cart  | Project List | Order Status | Help    

Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 04-17-2000, 10:02 AM
matthew merrill
Posts: n/a
I have been experiencing what I describe as a pre ignition ping in a gas engine in my 78 300d.
This ping noise happens at all different speeds. I am thinking it may be caused by a injector that is dirty and dripping fuel. Does this sound correct? Would a good fuel conditioner / injector cleaner eliminate the problem? Thanks, Matthew Merrill
Reply With Quote
Old 04-17-2000, 10:54 AM
Registered User
Join Date: Mar 2000
Location: Southampton, NJ
Posts: 126
I always thought that the "D" in 300D meant that the engine was a diesel and, yeah, you may have a "ping" if you put gas in there. Correct me if I am wrong.
Reply With Quote
Old 04-17-2000, 11:32 AM
matthew merrill
Posts: n/a
OK, Zachv,
Yeah D stands for Diesel, and not Dimwit.
I was using the analogy to describe the noise.
I have not put anything but diesel in the car. Any ideas why it would make this noise.

Reply With Quote
Old 04-17-2000, 04:17 PM
Registered User
Join Date: Jan 2000
Location: New Bedford, MA USA
Posts: 1,583
You may be hearing a bad injector or fuel distributor noise. with the engine running, see if you can hear the noise, put a fingertip on each injector and see if you can feel any mechanical vibration.

Jeff L
1987 300e
1989 300e
1987 BMW 325
Reply With Quote
Old 04-17-2000, 04:46 PM
Registered User
Join Date: Feb 2000
Location: Santa Clarita, CA, USA
Posts: 133
I experienced the same thing in my 84 300SD about a year ago. It definitely sounded like a ping or nailing even over the usual "clack-clack" of the engine. I suspected a dirty injector and put in Red Line Diesel Catalyst. It's a synthetic oil and injector cleaner. After 5 min running with Redline in the tank, the nailing went away. It was probably due to the lubricating properties of the syn. oil. The problem came back on the next tank of fresh diesel. I figured the injector(s) must be really dirty or worn. I pulled the injectors out and tore them down. 4 of the 5 looked clean as a whistle and the pintle (or needle) inside the injector moved freely. 1 though was siezing up and when I managed to pull the pintle out, it was blue. I suspect water in the fuel combined with low sulpher diesel caused the injector to overheat from lack of lubrication. I ended up just buying a set of rebuilt bosch injectors for $45 each. I thought it wasn't that much considering I put on 260,000 miles on the 1st set of injectors.

In you case, I'd try Redline to try to clean/lubricate the injectors. I use Redline on a regular basis for the lubricating properties. One bottle is good for 100 gallons. Hope this helps...

Reply With Quote
Old 04-17-2000, 06:51 PM
Posts: n/a
When youtry to locate the exact source of the noise, try using a long socket extension or long screw driver like a stethwscope. Sound travels better and faster through dense objects. Since steel is much denser that air, when one end of the extension is held against the injector and the other end against your ear, youcan zero in on the cylinder. This is also effective for identifyiong the source of bearing whine in the belt driven component train.

87 300TDT
150,000 miles

Reply With Quote
Old 04-18-2000, 09:25 AM
matthew merrill
Posts: n/a
Well, I put a can of Red Line conditioner
in the tank yesterday. The "ping" has
decreased significantly. I have another
bottle for the next tank. Maybe this will
solve the problem.

Reply With Quote
Old 04-18-2000, 12:41 PM
Posts: n/a

Noone has mentioned anything about timing. I have a similar problem with a 240D engine I'm running temporarily. I plan on checking the timing this weekend. I'll let you know the outcome.

Say hello to my son if you see him around Austin, he's a Junior at UT.

Good luck,

Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles
Reply With Quote


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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
We often overlook Fuel Pump damage--Low Sulfur Fuels and bad fuel (85 300D) Carrameow Diesel Discussion 16 11-15-2007 05:43 AM
Opinions on purchasing a 1987 300D swogee Diesel Discussion 12 05-03-2005 10:27 AM
1976 W115 300D motor into 1979 W123 300D sebtowne114 Diesel Discussion 5 04-14-2005 07:26 AM
auto tranmission problem in 1981 300d o2pilot Diesel Discussion 2 06-15-2004 11:19 AM
300D turbo slushbox vs 300D n/a 4 speed The Warden Diesel Discussion 5 05-28-2004 12:40 AM

All times are GMT -4. The time now is 03:34 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page