SL/R129: 92-500SL dies wont start when hot
#27
Banned
Joined: Jan 2006
Posts: 1,982
Likes: 389
From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
The voltage is high 90% of the time and low 10%. Therefore, M-B regards your duty cycle to be 10%, and the diagnostic manual explains what this means and the troubleshooting steps to follow up with: http://manual.startekinfo.com/manual.../2_1/m11.jsp#3
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JeffNY (04-28-2019)
#28
I bought my '97 500 SL about two years ago with 51K miles on the odometer, and I immediately drove it 1400 miles from West Palm Beach to Dallas in 24 hours, stopping only to rest for a few minutes or a few hours to get sleep as needed. I had no problems until the next day when it failed to start hot in my garage. On my 1400-mile trip I probably started it hot 20 times or so. So I googled the problem and found a suggestion to replace the crankshaft position sensor. The article said that for a few hundred dollars an MB dealer would fix it, but that I could get one online for $20 or less. I believe I paid about $8 on Amazon including next day delivery. Problem was solved with about 20 minutes of labor. Since then the car has run virtually problem free for approx 5000 miles. I keep a spare crankshaft position sensor on my garage shelf, but I have read that they typically last about 50K miles. As I recall, the attachment bolt required a special socket that I found easily at Pep Boys. If I need another sensor in 50,000 miles, that will be 22 years from now, and I will be 98 years old. I will probably pay someone else to install it.
Last edited by jerryi; 05-07-2019 at 12:56 AM.
#29
Newbie
Joined: Feb 2019
Posts: 6
Likes: 0
From: NC, USA
1987 560SL, 2007 SL550, 2012 E350, 2010 c300
I bought my '97 500 SL about two years ago with 51K miles on the odometer, and I immediately drove it 1400 miles from West Palm Beach to Dallas in 24 hours, stopping only to rest for a few minutes or a few hours to get sleep as needed. I had no problems until the next day when it failed to start hot in my garage. On my 1400-mile trip I probably started it hot 20 times or so. So I googled the problem and found a suggestion to replace the crankshaft position sensor. The article said that for a few hundred dollars an MB dealer would fix it, but that I could get one online for $20 or less. I believe I paid about $8 on Amazon including next day delivery. Problem was solved with about 20 minutes of labor. Since then the car has run virtually problem free for approx 5000 miles. I keep a spare crankshaft position sensor on my garage shelf, but I have read that they typically last about 50K miles. As I recall, the attachment bolt required a special socket that I found easily at Pep Boys. If I need another sensor in 50,000 miles, that will be 22 years from now, and I will be 98 years old. I will probably pay someone else to install it.
Where did you buy the part at that price?
Many thanks
#30
I probably bought both of them (the first one and the 'spare') on Amazon. The 'spare' was $12.99 on June 13, 2098:
Sold by:
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#31
My guess is that your replacement sensor was not defective and that you need to look further for your particular problem. I doubt that there is an error code for the crankshaft sensor for this car, but I may be wrong.
#32
Same problem
I just found why mine is doing the same dies after 20 min then wait an hour for it to restart. I changed everything everyone has said to change with no luck Including the rewire. I did some soul searching and figure the mass airflow sensor was heating up And not working. After sticking it in the freezer for 15 minutes no change. I still figured it was an air fuel ratio problem. The map sensor was the next logical choice for me. I accidentally disconnected the EGR purge control valve re-generator. The car ran perfectly for 45 minutes, after trouble shooting for two years and not being able to drive it. Somehow it was allowing the EGR valve to open and screw up the air fuel ratio.
Last edited by Kurt Keppler; 07-26-2019 at 08:13 PM. Reason: Additional photo upload
#35
I had the same issue, changes the crankshaft position sensor and that didn't help. Installed new distributor caps and it has run flawlessly ever since. |I looked at the inside of the caps and one had carbon tracks from a couple of the contacts.
#36
I had the same problem. ! have a 95 S420 with 49k miles. My car ran fine for the first 20 minutes and then it would stutter then die. It needed to cool down for an hour or more, depending on the weather, in order to start again. After reading a number of forums this seems to be a common problem. I replaced the distributor caps and rotors as some of the forums suggested and that worked like a charm. I hope this helps.
#37
Dies?
Did anybody figure out this problem? I'm having the same problem with my 1990 Mercedes. SL500 5.0l, V8 R129 series. It does the exact same thing. Haven't been able to figure it out for months and shops can't figure it out either I have spent thousands of dollars trying to figure this problem out myself and other shops too! Please help me!
#38
Newbie
Joined: Feb 2019
Posts: 6
Likes: 0
From: NC, USA
1987 560SL, 2007 SL550, 2012 E350, 2010 c300
I just found why mine is doing the same dies after 20 min then wait an hour for it to restart. I changed everything everyone has said to change with no luck Including the rewire. I did some soul searching and figure the mass airflow sensor was heating up And not working. After sticking it in the freezer for 15 minutes no change. I still figured it was an air fuel ratio problem. The map sensor was the next logical choice for me. I accidentally disconnected the EGR purge control valve re-generator. The car ran perfectly for 45 minutes, after trouble shooting for two years and not being able to drive it. Somehow it was allowing the EGR valve to open and screw up the air fuel ratio.
1987 560sl 75K.
#39
Sounds like the same problem I had read this it fixed my problem
.https://www.benzworld.org/threads/co...#post-18056153
.https://www.benzworld.org/threads/co...#post-18056153
#40
I had the same problem. ! have a 95 S420 with 49k miles. My car ran fine for the first 20 minutes and then it would stutter then die. It needed to cool down for an hour or more, depending on the weather, in order to start again. After reading a number of forums this seems to be a common problem. I replaced the distributor caps and rotors as some of the forums suggested and that worked like a charm. I hope this helps.
I've been fighting this one since I purchased my 95 SL500 in 2016. I've logged about 40k miles since then with seven sets of caps/rotors during that time. Bosch, Beru, Bremi, doesn't matter. I've replaced the greenie wiring harness that biodegraded, plug wires multiple times, coils, fuel pumps, etc. Have a homemade code reader that works fine, the car just doesn't throw any codes when it fails.
The M119 is a love/hate thing. When the car runs, it is great. I'm considering giving it to St. Judes or the Kidney Foundation to get rid of it. Can't, in good conscience, sell the thing to anyone. In its price range, it would go to someone who likely couldn't afford or have the personal expertise to keep it going. I started driving when Gerald Ford was President. This is the only car in my life that I've ever had to have towed - towed several times in the last few years. Gosh...
#41
MBWorld Fanatic!
Joined: Mar 2016
Posts: 1,032
Likes: 127
From: SF Bay Area, CA
190E 2.6L 1989, 190E 2.6L 1988, BMW 535dXdrive 2014, BMW 428i 2015
Although the Distributor Cap high voltage issues study mentioned in that BW article is super interesting, it must be a fringe issue of an aging distributor cap and/or humitdy problems. I had M103 and M104 engines. For the past 35 years I have owned these cars/engines I have never had that High tension ignition problem. I'm sure it happens but very rarely as owners of the M103 hardly ever experience that issue. Especially in well cared for cars that are in-tune.
Now for the M119 with much more complicated EZL this must be a low voltage side of the ignition control loop, or at least it involves all the "extra" EZL inputs included in the M119. It is a lot more complicated than the M103 with knock sensors, camshaft position sensor, transmission overload sensor, etc, etc.
At the risk of stating the obvious, one would have to first test all the sensors mentioned above at room temp and see how they go out of spec at temp. I suspect a multimeter is all that is needed for the sensors. And if they all are within spec at hot temp than the arrow points in the EZL unit itself. The only common suspect sensor between the M103 and M119 is the crankshaft position sensor. And that is the only sensor that ages on the M103 and can cause no start or engine dying at temp when warm. That was already tested/replaced here so now the rest of the sensors need to be tested. And if all those sensors are vindicated, you are left with suspecting the EZL itself. It is a lot more complicated and probably prone to failure. The M103 EZL is solid. Hardly ever fails but it is a much simpler design.
If you want to do a binary search between the EZL and all it's inputs. Get a can of freeze-it spray. Run the car to temp till it fails. Spray the freeze-it or any other chiller on the EZL and see if it immediately fixes the problem. If it does not, then you have to go chasing a sensor failure at hot. If it does than you need a new EZL. And if some of the sensors are accessible, you can try this trick on them too.
- Cheers!
Now for the M119 with much more complicated EZL this must be a low voltage side of the ignition control loop, or at least it involves all the "extra" EZL inputs included in the M119. It is a lot more complicated than the M103 with knock sensors, camshaft position sensor, transmission overload sensor, etc, etc.
At the risk of stating the obvious, one would have to first test all the sensors mentioned above at room temp and see how they go out of spec at temp. I suspect a multimeter is all that is needed for the sensors. And if they all are within spec at hot temp than the arrow points in the EZL unit itself. The only common suspect sensor between the M103 and M119 is the crankshaft position sensor. And that is the only sensor that ages on the M103 and can cause no start or engine dying at temp when warm. That was already tested/replaced here so now the rest of the sensors need to be tested. And if all those sensors are vindicated, you are left with suspecting the EZL itself. It is a lot more complicated and probably prone to failure. The M103 EZL is solid. Hardly ever fails but it is a much simpler design.
If you want to do a binary search between the EZL and all it's inputs. Get a can of freeze-it spray. Run the car to temp till it fails. Spray the freeze-it or any other chiller on the EZL and see if it immediately fixes the problem. If it does not, then you have to go chasing a sensor failure at hot. If it does than you need a new EZL. And if some of the sensors are accessible, you can try this trick on them too.
- Cheers!