engine misfiring - 1993 300E
Thread Starter
Newbie
Joined: Nov 2007
Posts: 6
Likes: 0
1993 300E 3.2L
engine misfiring - 1993 300E
Hi guys. About a week ago I started to notice that my acceleration was getting really rough/bumpy, and wouldn't jump to the next gear very easily. It has gotten worse, and now I can barely accelerate without my front end vibrating pretty badly. Keep in mind that a month ago I was able to haul *** and reached 120 mph a few times, with no engine problems.
Anyway, a friend of mine rode in the car with me and said that my engine is definitely misfiring. Today I changed my oil and transmission fluid, both with mobil 1 synthetic, which didn't change the problem. Now, I'm thinking that it could be my spark plug wires (which haven't been replaced since the car was made), my distributor, or my ignition coil. The last time I replaced my spark plugs was about a month ago, and I put in Bosch +4 Platinum, but I didn't replace the wires at the time. Should I go ahead and replace the wires and see if it still happens? If so, what are my next steps? Thank you so much for reading this. Take care.
Anyway, a friend of mine rode in the car with me and said that my engine is definitely misfiring. Today I changed my oil and transmission fluid, both with mobil 1 synthetic, which didn't change the problem. Now, I'm thinking that it could be my spark plug wires (which haven't been replaced since the car was made), my distributor, or my ignition coil. The last time I replaced my spark plugs was about a month ago, and I put in Bosch +4 Platinum, but I didn't replace the wires at the time. Should I go ahead and replace the wires and see if it still happens? If so, what are my next steps? Thank you so much for reading this. Take care.
Last edited by pipesurfer; Dec 20, 2007 at 09:06 PM.
MBWorld Fanatic!
Joined: Dec 2006
Posts: 1,042
Likes: 1
From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
Welcome to the forum! 
One problem is Bosch +4 Platinum plugs. You need the standard plugs for this engine. Platinum plugs do not work well in the M104, and the Bosch +4 is nothing but a marketing gimmick. I'm sure in the next 5 minutes someone here will chime in with the correct spark plug number, or you can do a search on this forum. I know it has been discussed.
I personally would not use synthetic oil as this engine was not designed for it, but that subject is like politics and religion around here!
One problem is Bosch +4 Platinum plugs. You need the standard plugs for this engine. Platinum plugs do not work well in the M104, and the Bosch +4 is nothing but a marketing gimmick. I'm sure in the next 5 minutes someone here will chime in with the correct spark plug number, or you can do a search on this forum. I know it has been discussed.
I personally would not use synthetic oil as this engine was not designed for it, but that subject is like politics and religion around here!
Last edited by shdoug; Dec 20, 2007 at 12:40 AM.
MBWorld Fanatic!
Joined: Jun 2005
Posts: 1,496
Likes: 7
From: Socialist West Coast
95 E320, 19 Ram 1500 Hemi, 21 GLS 580(wife)
Within the combo of those plugs and that oil could lie your problem. Those plugs do not work well, I use some NGK's, and as mentioned the oil is not the best choice for that motor since the seals will leak with that thin of oil... which leads me to believe that you got oil past your valve guides or rings and fouled up those fancy plugs. I'd pull them to see how they look.
Thread Starter
Newbie
Joined: Nov 2007
Posts: 6
Likes: 0
1993 300E 3.2L
Hey guys, thanks for the replies.
Just now as I was driving home, I stopped at an intersection and my car almost died; the engine started to jerk back and forth and I almost lost all power, but thankfully my house was right there so I made it.
I have a few questions now:
A) Exactly which NGK spark plugs do you use? Just the regular copper ones?
B) Which oil do you recommend, and which type? I used Mobil 1 synthetic 10W-30. Also, is it bad to completely switch to another oil when I've been using this kind for a while?
C) Should I still replace the spark plug wires, and which type should I buy and where?
Thank you so much everyone.
Just now as I was driving home, I stopped at an intersection and my car almost died; the engine started to jerk back and forth and I almost lost all power, but thankfully my house was right there so I made it.
I have a few questions now:
A) Exactly which NGK spark plugs do you use? Just the regular copper ones?
B) Which oil do you recommend, and which type? I used Mobil 1 synthetic 10W-30. Also, is it bad to completely switch to another oil when I've been using this kind for a while?
C) Should I still replace the spark plug wires, and which type should I buy and where?
Thank you so much everyone.
Newbie
Joined: Dec 2007
Posts: 3
Likes: 0
Land Rovers!!!
hey sean - read everything in this searched thread link:
https://mbworld.org/forums/search.php?searchid=3540671
like we talked about, best case scenario, plugs and wires and whatever those evil mercedes voodoo coilpacks between wires are.
I've read a lot of people get slipped valve guides - which blows ***, but buy a new head and we'll fix it. Some have low compression like we talked about, but with smoking symptoms - which you dont have. . . yet. Another guy said he fixed this with a new tps, another had driven it for a while like this and it ended up being a ****ed ecu that he replaced for mad bucks.
You should've bought that Great Divide Range Rover for $1500!!!
GET TO THAT MB SHOP and have them do a full diagnostic. All of the above parts are expensive and before we start throwing $$ and parts at it, get someone's opinion who sees this every. Look on the bright side, at least your seat switches still work. . . wait a sec. . .
Don't stress, we'll figure it out.
On second thought if you have AAA, tow it to Matt's place in the OC. He's a friend and knows what he's doing. . .
https://mbworld.org/forums/search.php?searchid=3540671
like we talked about, best case scenario, plugs and wires and whatever those evil mercedes voodoo coilpacks between wires are.
I've read a lot of people get slipped valve guides - which blows ***, but buy a new head and we'll fix it. Some have low compression like we talked about, but with smoking symptoms - which you dont have. . . yet. Another guy said he fixed this with a new tps, another had driven it for a while like this and it ended up being a ****ed ecu that he replaced for mad bucks.
You should've bought that Great Divide Range Rover for $1500!!!
GET TO THAT MB SHOP and have them do a full diagnostic. All of the above parts are expensive and before we start throwing $$ and parts at it, get someone's opinion who sees this every. Look on the bright side, at least your seat switches still work. . . wait a sec. . .
Don't stress, we'll figure it out.
On second thought if you have AAA, tow it to Matt's place in the OC. He's a friend and knows what he's doing. . .
Last edited by eliaschristeas; Dec 21, 2007 at 01:10 AM. Reason: another idea
Newbie
Joined: Dec 2007
Posts: 3
Likes: 0
Land Rovers!!!
another interesting thread:
https://mbworld.org/forums/e-class-w124/222526-new-300e-owner-looks-good-runs-like-crap.html
talks about fuel, vacuum lines etc. You deffinatley need to get the shop manual if you're keeping this thing. It'll help you with all this!
can someone tell him where the dizzy is located on this car? He'll need it for cap and rotor maint.
also, does this things have an obd code reader box somplace? All the old rovers - aka german cars disguised as evil british electrical engineering - have obd 1 ports under the passangers seat.
https://mbworld.org/forums/e-class-w124/222526-new-300e-owner-looks-good-runs-like-crap.html
talks about fuel, vacuum lines etc. You deffinatley need to get the shop manual if you're keeping this thing. It'll help you with all this!
can someone tell him where the dizzy is located on this car? He'll need it for cap and rotor maint.
also, does this things have an obd code reader box somplace? All the old rovers - aka german cars disguised as evil british electrical engineering - have obd 1 ports under the passangers seat.
Last edited by eliaschristeas; Dec 21, 2007 at 01:08 AM.
Trending Topics
Member
Joined: Apr 2005
Posts: 87
Likes: 0
From: Los Angeles, CA
95 E300D
I had same problem with my 96 e320 I took my car to the MB mechanic he told me he knows whats the problem and problem was ignition coil, i got it changed for 80 and engine was running perfect....
MB World Stories
The Best of Mercedes & AMG
8 Oddball Mercedes Ideas That Actually Made it to Production
Verdad Gallardo
Dubai Tuner Gives the Mercedes G-Class An Entirely New Look
Verdad Gallardo
Six Gift Ideas Your AMG Loving Dad or Grad Will Cherish
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
MBWorld Fanatic!
Joined: Dec 2006
Posts: 1,042
Likes: 1
From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
Changing the oil has nothing to do with how it runs. Oil protects the bearings and lubricates the internal engine parts. It has a lot to do with how long your engine will last, and more importantly how long it will remain leak-free.
Last edited by shdoug; Dec 22, 2007 at 12:06 AM.
Thread Starter
Newbie
Joined: Nov 2007
Posts: 6
Likes: 0
1993 300E 3.2L
Thanks again guys. That explanation of the coil packs and wires was very helpful. Tomorrow I'm going to buy some new spark plugs; exactly which kind should I get? I was thinking NGK V-Power, but I want to be sure I get the right kind.
MBWorld Fanatic!
Joined: Jun 2005
Posts: 1,496
Likes: 7
From: Socialist West Coast
95 E320, 19 Ram 1500 Hemi, 21 GLS 580(wife)
Very happy with them.
MBWorld Fanatic!
Joined: Dec 2006
Posts: 1,042
Likes: 1
From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
I think I spent about $8 on some AC Delcos and it ran like a scared rabbit/scalded dog. The head and cam are so perfectly designed that just a plain, simple plug works great. It's not a Honda Civic after all. But it's your money.
Thread Starter
Newbie
Joined: Nov 2007
Posts: 6
Likes: 0
1993 300E 3.2L
Next step was to replace the ignition coils. I ordered 3 Bosch ignition coils and replaced them. Still, the same problem, although the problem is even less violent now, but it's still misfiring and shaking pretty badly when I'm accelerating and when I'm going under 10 mph.
You say there is no distributor cap and rotor. Does that mean there isn't a distributor at all? I'm a little confused by this, seeing as how I'm still fairly new to cars. And given that there isn't a cap or rotor to replace, what is my next step? I should probably replace the other 3 wires as well but I don't think that'll be the entire solution to the problem.
If anyone could post a diagram of where the distributor is or post a link, or has any more insight on this, it would be greatly appreciated. Thanks guys.
