Mercedes-Benz Forum - Reply to Topic
Topic: Need help! Engine Misfire Saga On 99 S500 Reply to Thread
Title:
Message:
Trackback:
Send Trackbacks to (Separate multiple URLs with spaces) :
Post Icons
You may choose an icon for your message from the following list:
 

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










  Additional Options
Miscellaneous Options

  Topic Review (Newest First)
06-14-2019 02:04 PM
1994v12 ASR and ABS lights on ? check fuse #23 in fusebox under hood, also pull ALL fuses in that box and visually inspect them, spray the fusebox slots with electrical cleaner ($4 at any Walmart, red can in automotive dept.) reinstall all fuses. check to make sure none are burned (mine had burned fuse for interior power options, and corroded #23 for ASR switch, stop light).

then open the big coffin box holding the 4 fuses in the last ECM. do the same with them. if one of those is burned, it will set the ASR/ABS lights and go into limp mode and run like a bucket of schit.

then, pull battery cable, and wait 30 seconds, then reattach and start.

if you still got the ASR/ABS, slit open the harness wiring sheaths going to the MAF sensors and the ETC throttles, and check for deteriorated shorted wiring. a quick check with a digital ohmmeter, check all pins in the connector to ground they should be the same values for both sides. if one side is way off different, then you have shorted wiring somewhere between the MAF's and/or ECT's and the ECM's in coffin box.


Quote:
Originally Posted by BNBN View Post
Unfortunately, I do not know how to find my forum or my replies unless someone send me a personal message on my [email protected] or is in my private messages. OK all plugs, wires,injectors, boots,MAS Sensor have been changed in the 199 S 500 with only 112,000.00 miles car parked from last 10 years driven once a month for may be ten miles. Even pulled out ECU and had it reviewed and cleaned as one mechanic said neither its burn nor any smell or broken points. Its been almost 6 moths from one mechanic to another and no one can figure out except only P308, ASR and ABS Light. # 8 suppose to have the pressure(now I forget names of things so use what I can). Mechanic said had opened the [email protected] Sensor and looked at CAT and it is fine. Also CAT does not make a different noise then rest when hit with hammer. I don't want to give up. In addition to prayers anyone interested in the Prize or gift, please let me know. Fuel filter and pump seems to be working fine.

Thanks
06-12-2019 02:13 PM
z168 I was reading through the first posts to realize this is 8 years old.

I dont have any dampness issues but Ive replaced 3 coils in the last 8 months. I might just decide replace the remaining and get it over with. Good news is the coils on a late model M119 are easy to replace
06-10-2019 10:35 PM
BNBN
1999 S 500 Misfire front Driver side cat turns red after 10 Min

Unfortunately, I do not know how to find my forum or my replies unless someone send me a personal message on my [email protected] or is in my private messages. OK all plugs, wires,injectors, boots,MAS Sensor have been changed in the 199 S 500 with only 112,000.00 miles car parked from last 10 years driven once a month for may be ten miles. Even pulled out ECU and had it reviewed and cleaned as one mechanic said neither its burn nor any smell or broken points. Its been almost 6 moths from one mechanic to another and no one can figure out except only P308, ASR and ABS Light. # 8 suppose to have the pressure(now I forget names of things so use what I can). Mechanic said had opened the [email protected] Sensor and looked at CAT and it is fine. Also CAT does not make a different noise then rest when hit with hammer. I don't want to give up. In addition to prayers anyone interested in the Prize or gift, please let me know. Fuel filter and pump seems to be working fine.

Thanks
04-17-2011 09:50 PM
S500Joe
Solved!

Thanks to everyone for their input. Finally warmed up enough here in Minneapolis to get under the hood again. I pulled the coil, and sure enough, the area around the spark plug was damp/wet. Dried it out and no more misfire! To make things even nicer - the Check Engine light went out by itself on the test drive! I feel a bit sheepish for not checking this automatically - but the assistance all of you gave me helped me avoid an expensive visit to the dealership! THANKS!!!!!
04-15-2011 12:29 AM
nhzruthless818 i used the copper core plugs and they are not that good. mine i had two bad coils so i ended up replacing all so i dont go through repairs later also i had the expensive bosch plugs ($10 each and dealer said use oem only and to tell you guys the truth the expensive ones were better then oems)

i am running oems right now and they cause a misfire in the mornings but once warmed they are perfect. but the expensive ones were great in general.
04-15-2011 12:24 AM
syljua
Quote:
Originally Posted by S500Joe View Post
I am at a loss - any suggestions on the next step?
If you hear that your car is misfiring, I would make sure that you actually
did replace number 8, and not the other side.

These engines with coil-on-plug, are easier to fault find, since you are not
dealing with high tension on top of the coil.

Remove the air filter, and the cover. Then remove the low tension connector to each coil
in turn. Even more degraded running, its not that cylinder. No change, you
have found the candidate.

When you have found the cylinder, do a test where you swap the coil to
another location, but keep the plug. If the fault moves with the coil, well, its
the coil. If it stays, it should be the plug. Also do consider the high tension lead
between the coil and plug, in the same way.

I still think that you have water down one of the plug holes. Either blow it
off by air, or warm the engine up, without the cover on, to let it evaporate.

I've had both. Misfire after a to heavy engine wash, and a faulty coil.

br,
syljua
04-14-2011 11:59 PM
Merc-S600
Quote:
Originally Posted by S500Joe View Post
That helps! I never thought it might be a fouled/bad plug - but a great place to look. I'll pull the number 8 and replace. (The plugs are fairly new - less than a 5,000 miles on them so I think I will be ok on pulling just the one). Thanks again!
About a year ago or so doing my routine maintenance on the car , it didnt need anything as she drove flawless without any problems , however i changed ALL the sparkplugs etc ... and the Day after the engine didnt sound to good ,sort of misfiring on 1 cylinder ,i check't the plugleads etc... maybe one wasn't push'd in properly , still misfiring so i rang the mechanic if it could be a faulty sparkplug and he said that he would'nt rule it out (there is more to this but not important), anyway ,i board another set of NGK Sparkplugs ,changed them and all was good ,no more misfiring . Conclusion : Sometimes the new sparkplugs can be faulty ,1 is inaf to cause the misfiring .
(Next car i buy will be a V12 and rebadge it V8 ,so i have 4 spare cylinders & plugs ,looks like 8 aren't inaf ,LoL.) .
Ciao
BTW: i know i could have just unplugged 1 plug by 1 to see and find the faulty plug ,well last time i did that (different Car ,Alfa Romeo) i got electric shocked so never again will i do THAT ,i prefer to waiste 50 bucks & do the job again.
04-14-2011 09:53 PM
iss
Quote:
Originally Posted by S500Joe View Post
That helps! I never thought it might be a fouled/bad plug - but a great place to look. I'll pull the number 8 and replace. (The plugs are fairly new - less than a 5,000 miles on them so I think I will be ok on pulling just the one). Thanks again!
replace the spark plugs (ALL). Use the OEM plugs ONLY (Non-Resistor, Copper Core)
04-14-2011 06:56 PM
Mercedes mechanic I would bet that the live datastream reading's on the o2 sensor's are way out of whack. If you can do datastream, try watching the voltage on the o2 sensor. Starting out the fuel mixture will be a little rich. As it reaches operating temp the switch time should be within a half second or so. The voltage should be between .200v to .900v and switch from high to low and back every few seconds. The multiable misfire lead's me to believe that you are having a back pressure problem.

The only thing I can suggest if you can not do a datastream is to pull the plugs on the same side of the #8 cyl, see if they look differant on the electrode's from those on the opposing side. If one side plug set looks black and the other side does not you may need to look into it further.
04-14-2011 06:55 PM
S500Joe
Thanks!

That helps! I never thought it might be a fouled/bad plug - but a great place to look. I'll pull the number 8 and replace. (The plugs are fairly new - less than a 5,000 miles on them so I think I will be ok on pulling just the one). Thanks again!
This thread has more than 10 replies. Click here to review the whole thread.

Posting Rules  
You may post new threads
You may 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

 

Title goes here

close
video goes here
description goes here. Read Full Story
For the best viewing experience please update your browser to Google Chrome