SL/R129: 1995 SL500 - Misfiring & stalling - Need your help
Thread Starter
Super Member
Joined: Oct 2014
Posts: 505
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2016 E63s Wagon - CCB & CF package
1995 SL500 - Misfiring & stalling - Need your help
Hey all,
I have a 1995 SL500 with serious misfiring issues. May be important to note that the car has been sitting for months at a time last few years. May have been driven 1,000 in last 4 years. Its at 84,000 miles now.
Here's how it goes:
Once in a blue moon, the car will run 100% without any issues for a full day, but majority of time, that's not the case. It starts well and runs well for about 5-10 mins and then the issues start. It starts misfiring at idle and just can't get through it. Its not drivable and I end up limping home last few times. Yesterday it stumbled and stalled upon taking off from a light and wouldn't restart so i ended up pushing it 5-6 blocks (this things heavy!). It just kept on popping very loudly out of the exhaust but no start. Finally after 30 mins when it cooled off, started up again and ran rough.
I recently replaced air, oil and fuel filters, did an engine and trans oil change. Checked the plugs and they look totally fine, BOSCH plugs. Wires all looks good. Not sure where to go next.
It's getting air and i assume the loud pops are unburnt fuel in the exhaust so i think its getting fuel too. So somethings off with the ignition.
Any suggestions? I have heard that 1995 specifically had some engine wiring issues. Any thoughts? I can't seem to get a clear on answer on what the offending harness is and its part #.
Any and all help is greatly appreciated!
I have a 1995 SL500 with serious misfiring issues. May be important to note that the car has been sitting for months at a time last few years. May have been driven 1,000 in last 4 years. Its at 84,000 miles now.
Here's how it goes:
Once in a blue moon, the car will run 100% without any issues for a full day, but majority of time, that's not the case. It starts well and runs well for about 5-10 mins and then the issues start. It starts misfiring at idle and just can't get through it. Its not drivable and I end up limping home last few times. Yesterday it stumbled and stalled upon taking off from a light and wouldn't restart so i ended up pushing it 5-6 blocks (this things heavy!). It just kept on popping very loudly out of the exhaust but no start. Finally after 30 mins when it cooled off, started up again and ran rough.
I recently replaced air, oil and fuel filters, did an engine and trans oil change. Checked the plugs and they look totally fine, BOSCH plugs. Wires all looks good. Not sure where to go next.
It's getting air and i assume the loud pops are unburnt fuel in the exhaust so i think its getting fuel too. So somethings off with the ignition.
Any suggestions? I have heard that 1995 specifically had some engine wiring issues. Any thoughts? I can't seem to get a clear on answer on what the offending harness is and its part #.
Any and all help is greatly appreciated!
Last edited by V-AMG; Jan 8, 2017 at 12:11 PM.
Member
Joined: Jul 2008
Posts: 213
Likes: 31
From: SW Florida
1995 SL500 - 2017 AMG GLC 43
Have your local MB dealer pull a VMI to see if the harnesses were replaced. If not replaced, I'm sure they are wasted. Pull your distributor caps and clean them along with the rotors. I use a Dremel tool with a small SS wheel to clean them. If they are in real bad shape, replace them. Do you have a check engine light?
Newbie
Joined: Aug 2008
Posts: 3
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From: Metro St. Louis (Belleville,IL)
1987 190E 2.3 16V (W201) mine, 1993 300CE (W124) wife , 1994 E320W (W124) daughter,1995 E320 (W124)
The distributor caps are the likely suspect. Cleaning the contacts are an easy fix, replacing is probably not necessary.
Thread Starter
Super Member
Joined: Oct 2014
Posts: 505
Likes: 39
2016 E63s Wagon - CCB & CF package
Have your local MB dealer pull a VMI to see if the harnesses were replaced. If not replaced, I'm sure they are wasted. Pull your distributor caps and clean them along with the rotors. I use a Dremel tool with a small SS wheel to clean them. If they are in real bad shape, replace them. Do you have a check engine light?
Thinking about it some more today, it does run well once in a blue so i cant imagine its the harness. I feel like the harness issue would always be present, cant imagine it'd run well for first 10 mins then develop symptoms. Im starting to lean towards the distributors.
Here is what im planning to replace, items 23,20,17,14. Is there anything im missing? Do you happen to know what 38 and 5 are and if they should be replaced too?
Last edited by V-AMG; Jan 9, 2017 at 06:52 PM.
Thread Starter
Super Member
Joined: Oct 2014
Posts: 505
Likes: 39
2016 E63s Wagon - CCB & CF package
I bought all Bosch replacements from RMEuropean. Bought the caps, rotors, bowls and bowl gaskets for under $300. I'll tear into it and see what needs replacing then return the rest. Heard BERU may be better quality but i only found their cap. No rotor, bowl or gasket, so Bosch got my order (hopefully it'll be all right).
Lee Wireless,
What are thoughts on the harness? Should i buy it and have that ready too?
Car is parked nearly 2 hours away so when I go to it, i'd like to make sure I have everything i might need.
Thanks for the help and suggestions!
Lee Wireless,
What are thoughts on the harness? Should i buy it and have that ready too?
Car is parked nearly 2 hours away so when I go to it, i'd like to make sure I have everything i might need.
Thanks for the help and suggestions!
Last edited by V-AMG; Jan 10, 2017 at 07:07 PM.
Member
Joined: Jul 2008
Posts: 213
Likes: 31
From: SW Florida
1995 SL500 - 2017 AMG GLC 43
I bought all Bosch replacements from RMEuropean. Bought the caps, rotors, bowls and bowl gaskets for under $300. I'll tear into it and see what needs replacing then return the rest. Heard BERU may be better quality but i only found their cap. No rotor, bowl or gasket, so Bosch got my order (hopefully it'll be all right).
Lee Wireless,
What are thoughts on the harness? Should i buy it and have that ready too?
Car is parked nearly 2 hours away so when I go to it, i'd like to make sure I have everything i might need.
Thanks for the help and suggestions!
Lee Wireless,
What are thoughts on the harness? Should i buy it and have that ready too?
Car is parked nearly 2 hours away so when I go to it, i'd like to make sure I have everything i might need.
Thanks for the help and suggestions!
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Thread Starter
Super Member
Joined: Oct 2014
Posts: 505
Likes: 39
2016 E63s Wagon - CCB & CF package
Side-note: pulled the VMI and no harness replacement. We bought the car 5 years old so it the car would've been to new for the original owner to do it and we havent done it. VMI confirmed.
As mentioned, I bought caps and rotors to swap. Car's been sitting in a garage for 10 days without touched and when i took the caps off, full of condensation. Luckily no oil residue, but it was WET (see attached). The contacts were totally corroded too. Installed the new caps, rotors and bowl gaskets (very easy by the way - 1hr max) and voila! She fired right up and ran like a top. Drove for about an hour or two, shut off multiple times and no signs of misfire at all.
All in all, great success!
Last edited by V-AMG; Jan 19, 2017 at 01:45 PM.
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