Last night my 85' 380SL died while driving home from a cruise after about 200 miles on the road. Fortunately it was close to home and I had it towed to my Indy. The engine just suddenly cut out as if I flicked a switch indicating to me it was an ignition issue. I pulled off the road and it immediately restarted. I was able to drive it about 2 miles when it died again, and this time there was no restarting. Just cranked. Had it towed to my mechanic. This morning I went over there and he turned the key and it instantly started right up. :-(
I was suspecting perhaps the ECM may be on its way out and he suspects so too. He noted that r107s are known for ECM issues like this.
What do you sages think? Time for a new ECM or are there other less obvious likely suspects?
And yes he is going to check the coil, cap and rotor etc.
Another side thought: can a bad fuel pump relay unit interrupt the ignition system in this car?
Sure is a lot cheaper. You can almost afford to fry your ECU
When I did a few years ago I paid several hundred $ for a rebuilt Bosch, which seemed a bargain compared to the $2000+ for a new unit.
Hey thanks Rowdie and Aussiemerc for the info! Interesting...... I wonder which relay that could have been????? If you recall let me know and I'll pass it along to my Indy. Make his task possibly just a bit easier!!
Yreah I actually felt very unhappy when it started right up yesterday. Nothing beats an intermittant fault......... :-(
Could be another cause, however............like plain old "past it's best before date".
I've said it before and I'll say it again...............everyone wants the stupid MB tool kit and first aid kit to keep the car original but hardly anyone keeps a spare FPR in their glove box...JUST IN CASE.
Easiest relay to replace and chances are...might solve the "car just died" problem.
Actually, I DO have a spare fuel pump relay in the trunk, and when I talked with the mechanic this morning I told him if he checked and the relay was suspect to swap it out. However I was not aware - and perhaps someone here can tell me - if a failing fuel pump relay has the ability to cut out the ignition (or engine control) ot the engine and / or ICM?????
I thought that the FPR controlled only the on and off current to the fuel pump. What other interactions does it have????
Finally, if the FPR is getting bad, can it work intermittantly for awhile? I am pretty sure this FPR has been in use for approxamately 60,000 miles or a bit longer. It was installed a few months before I acquired the car from the previous owner, who threw in the extra FPR when I bought it.
Unless I missed it, you are assuming the ignition is cutting off... Still, the FPR is also your rev-limiter (on later models), and these cars positively will NOT run without fuel pump pressure. I vote FPR, but ICM is not out of the realm of possibility.
And yes, intermittent operation is not only possible, it happened on my 560SL, nearly stranding me (locally, thankfully)
As to Ears comment: yes, no engine will run without fuel. My observation is that when a carbureted car's fuel pump dies the engine will go into what I call "fuel starvation mode" where the engine will suddenly begin losing power and RPM but will attempt to continue running as long as there are fuel vapors in the carburetor. Typically the car will lose power quickly, yet attempt to surge a bit as remaining fuel vapors and gasoline droplets get sucked into the intake manifold. In my Benz' case it seemed as though the engine just cut out instantly, no attempting to revive or surge.
Now obviously, this is a fuel injected engine and I have never had the pleasure of experiencing just what a fuel injected engine does when fuel supply to the injection system ceases - in other words does it stumble and die or does it just cut out as though you were switching off the ignition? And also, Ears, you mentioned that on later models the FPR also served the function of rev-limiter. My car is an 85' 380SL and I'm not sure if this function is provided by the FPR, but assuming for a moment that it is, if the FPR fails, would the loss of that rev-limiting signal functionality result in an instant ignition cutout or similar thereby causing the engine to just shut down rather than stumble and starve for fuel???
As to Nobby's comment: I agree 100%, overheating could cause failure - very well put. I seem to recall after driving the car last week on a roughly 75 mile jaunt pulling into the garage and hearing the fuel pump whining a bit. When I restarted the car a couple of days later I did not notice the whining of the fuel pump, it sounded perfectly normal.
All of that said, I think I'm going to tell my Indy to swap out the FPR and also replace the fuel filter, in case it is clogging and placing a strain on the pump, and see where are are at that point. I'll keep you guys posted and really appreciate your input!
And also, Ears, you mentioned that on later models the FPR also served the function of rev-limiter. My car is an 85' 380SL and I'm not sure if this function is provided by the FPR,
YOUR FPR does a couple of things. It obviously acts as a fuel pump relay but is also a safety device.
If the engine is not running............the FPR will NOT cycle the pump. So, for instance, you get into a car accident and the engine stops.........the pump won't keep pumping fuel......which is a good thing if there is a system breach. It also acts a a safety device for your engine. It won't let you rev the engine past it's red line.
It gets all it's signals from the ....coil / tach?? This part I can't seem to remember.
Typically it would be an ECU.....but even I don't have one of those so it must be something simpler.
I see that Programa sells rebuilt units reasonable. Id go with one of theirs if I need one. So far no word from my indy but he has a couple cars ahead of me. I'm patient
-George-
Actually I stand corrected Rowdie. I forgot about this listing. $42. is pretty good deal, doesn't look like the original but who cares................... I just wanna get there!
My apologies for not updating sooner. Car still in the shop. My regular Indy is up to his eyeballs with other Cars to get me out fast so we took it to another Indy who specializes in older Mercedes cars. He told me to go ahead and order the upgrade (new design) ICM from Autohauz that Rowdie suggested because "..,I'll check it but I 100% assure you it's the ICM based on your description of the fault". This dude had been working on vintage Benz cars since the 80s and knows his stuff. And yes he orders from Autohaus all the time. Besides, if it ends up being something else, for $43 bucks I'll throw it on the shelf because according to what I've been reading.... the icm WILL fail eventually. So best get ahead of it.
Well guys, I'm happy to share the solution to my issue with you. Got the car back last night from the Indy. The immediate cause of failure was the ICM. We put in the $43. part that Rowdie recommended and she fired right up and is perfect.
While he had it he noted alot of moisture and crud in the fuel tank. So he drained and cleaned the tank, blew out all the lines and replaced the fuel filter and fuel pump which had become damaged from the moisture. He also did a proper tune up, with new plugs, Mercedes-Benz ignition wires, cap and rotor and he tweaked the air mixture slightly on the fuel distributor.
Holy cow! It has never run and idled this well in the 3+ years I've owned it. Heck, the car just flew over Jugtown Mountain on I78 :devil back to Easton PA and it idles and purrs more smoothly than I've ever experienced it. Another thing Ive noticed is that the engine starts after running warm and sitting a while and comes right down to proper idle. Typically in the past it would idle poorly for a couple of minutes and even die out if you didn't keep your foot lightly on the gas, then it would even out and idle OK after that. Not anymore. I would guess that rail pressure is probably higher now and not crap in the lines is a big plus....
And its all just in time, too. My local MBCA Chapter is having a 190SL concours in Bethlehem and I think I'll go over in my 107 and check it out :grin
Yeah, thats fer sure. But "peace of mind" is priceless (apologies to MasterCard)
However, this is really the first time this car has actually needed any "real repairs" since I've owned it. Everything else has been pretty simple stuff, like the idle control module or a couple blown aluminum fuses that fatigued here and there. So I consider myself pretty darned lucky..... These things don't run for free.
-George-
I have a 380 SL. Recently it stalls and turns off after being on for 5-10 minutes. I have taken it to the dealers and they are unable to find out what is wrong and have had a number of mechanics looking at it. Please advise me what I need to look for.
If you haven't it done already....please complete your profile with year and model.
Trust me....this will help you in the long run.
---->click on your icon (top right hand corner of your screen)
----> click on Account Settings
---->go to Account Details
----> add vehicle details
---->ADD your make model YEAR
----> click save.
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