1999 E300 intermittent shut off
 

Hi guys, you folks have helped me out several times over the years and I'm asking for your help again on a very frustrating problem I am having. The engine will die after idling anywhere from 15-30 minutes. I have replaced the crankshaft sensor with a new OEM (from Mercedes dealer) and the car ran great for 3 weeks then died again on the freeway. The car will not restart unless it sits for several hours to cool down, then it will restart. I had it towed to a Mercedes repair shop and this is what they have done.

" (1) Check engine light illuminated. Scanned for faults in ME and found the following: P1615:Control module voltage. P1330: Starter control. Both faults were current with engine running and do not change state when engine stalls. (2) Checked for drive authorization. Drive authorization present when engine stalls and no drive authorization faults current or stored. (3) Tested power input to ME and battery voltage is always present even when engine stalls. Checked resistance of ME grounds, all good. (4) Performed visual check of ME connector, wiring harness and crank sensor connector. No problems found. Double checked installation of crank sensor, no problems found.(5) replaced crank sensor to rule out faulty replacement part. (6) Installed new K40 relay. (7) Installed new fuel shut-off valve. (8) Removed all ME and sensor grounds, cleaned and reinstalled. (9) Checked power supply to fuel actuator on injection pump while engine stalled and power supply always maintains battery voltage.
Unable to find root cause of engine intermittent stalling at this time"

They sent me an invoice for $1365.44 and told me to make arrangements to have my car removed from their property!

when it does not want to start, do you see the RPM needle move up at all from 0 while cranking?

I will take a look at that when I get the car back home. What would it mean if the needle does move up from 0 while cranking, or does not move?

Sounds more like it is fuel related. Change the fuel filters. When changing filters, do it with a full fuel tank and the front of car point down hill from fuel tank.

I did change filters just the way you described and that did not solve the problem either, It's very frustrating. I don't what else to look for at this point.

When you don't even want to answer the questions we ask you, then how would anybody be able to help you

Sounds like you just got a bad CPS.

I'm sorry I thought I did answer the question. I will check when I get the car home next week.

I'm sorry I thought I did answer the question you asked. I will take a look at the tachometer when I get the car home next week.

Why ask questions when you don't even have the car near you and you are not even working on it now?

Well I'd guess its because he has a job, family, life commitments that set things up so that he can't be on-line waiting for your latest diagnostic remarks?

Good grief, take a chill pill.

This situation with diagnostics on computer controlled fuel injection systems are becoming more and more common as these cars age out. The work the shop did is exactly what I would have done, and it is what I have done, in diagnosis for cars that present with your symptoms. I've worked on a CLK500 and an E320 CDI that also have intermittent running issues that I can't isolate from checking codes and running scopes on sensors that potentially can shut down the car. The crank sensor is a common issue but at this point after you've replaced it twice and verified the wiring it seems unlikely that its the root cause.

As a software person in my working life I've always kind of been unimpressed with the diagnostics that are available in the internals of the Bosch ECU's. It just seems like with the myriad of sensors/data the ECU is monitoring it should be possible for a car to continue to operate with a bad crank sensor. For example these cars also have a camshaft position sensor - if the software starts to get a less than acceptable/understandable data set from the crank position sensor it should be able to recognize this, log it as an issue and then try to obtain the needed information from one of the other sensors by inferring the needed values from a combination of other data/sensors.

But that doesn't happen - I've replaced dead crankshaft position sensors that intermittently shut down the car and didn't throw a single code.

But for some sensors like air-mass the car will continue to run if the air-mass sensor is presenting bad values of even if its totally unplugged?

I guess a different person worked on that part of the code? Who knows? It's annoying to say the least.

The only way I've been able to diagnose/fix cars that have persistent intermittent issues as your car is experiencing is by swapping out ECU's to eliminate the ECU as an issue, and I have seen intermittent bad ECU's. Unfortunately you need to have a spare ECU and in many cars of this era the ECU is married to the EIS key, so you also need to have one of those as well. This means the person working on the car has to know this and be available to locate and then remove the required parts from another car in a junkyard and install them in your car as a diagnostic exercise. There are also electronics inside the injection pump for cars of this period so there could be electronic issues there are well. Nobody is willing to do this for a 25 year old car so it goes to the scrap pile.

Another possibility is to just blindly replace ECU's and wiring harnesses in a shot-gun type diagnostic approach but many ECU's for these cars a no longer available from Mercedes at any price. Even if they were the price would exceed the value of the car.

I don't really have a solution to your problem, just wanted to express my experiences when I've been in your shoes.

How nice is the car? I see you're a packerfan? Is the car in Wisconsin? A w210 that's spent more than a handful of winters in that environment has got to be very crusty.

Well hello Tim. Thanks so much for the in depth explanation.
The car is in near perfect condition, yes I live in Wisconsin but the car goes into storage in November before the snow flies and does not come out until late May when all the snow has melted. I got the car about 9 years ago from Arizona so it has never seen snow or salt. I would give the car a 9 out of 1-10, with 10 being the best only because the headliner is sagging slightly near the rear. Other than that the car is perfect, people come up to me all the time asking where I found such a nice car in near perfect condition! with that being said I am desperate to get the stalling issue repaired but at the same time I keep asking myself how much money do I want to keep spending ?
The car is at a shop in Milwaukee (about 100 miles from me) that works on Mercedes exclusively and they are telling me they tried everything they can think of. The Mercedes dealerships I have talked to tell me they send their customers with older cars to this same shop in Milwaukee so I don't even have the opportunity to take it anywhere else.

Given the age and intermittent nature of the issue, I would suspect a short to ground somewhere in the harnesses. These are difficult to find, especially if temperature related expansion is what leads to the short.

Given that, and in general if this is a keeper, it may be a good opportunity to insulate all harnesses and wiring that runs on, over, near the engine and chassis in the engine bay. Pay attention to any areas with a high heat load, near exhaust etc. And the component connectors.

If that doesn't solve it, you could also have fractured/weak solder connections in some of the key relays or ECU. Usually these will be at the pins to the board where the harness plugs into. There are many videos on how to both here and youtube.

It's a lengthy process to sort out, but at least in going thru the process you can also eliminate potential sources in the process.

Good luck

Thank you sir. I will do as you suggest. Sometimes I think it could heat related because the engine will run for 15-30 minutes before it dies and will not restart until it sits for a few hours to cool down. Other times it will run just fine for 2-3 weeks without issue and poof...the problem is back again.

It's almost certainly some sort of electrical issue. Could be in the wiring harness, ECU or the injection pump itself. The fact that it can run for 2-3 weeks is a huge problem for diagnosis - it's a show-stopper for anyone but the most die-hard OM606 enthusiast.

The diesel injection system used on the OM606 turbo is the last of the in-line injection pumps that can trace its roots and basic operating principles all the way back to the 1930's and 1940's. However it also has the unfortunate 'feature' or 'evoluiton' where the pump rack is under direct computer control and supervision. If the computer isn't involved the car is inoperable.

As such it kind of has the worst of both worlds, you have to have computers in the process to run the car BUT you still have all the disadvantages of the early IDI engines, prechambers, only one injection event per combustion event, relatively imprecise timing, inability to alter fueling for each injector ect, ect that the later CDI engines nicely provide for a huge bump in power, refinement and economy.

The shop in Milwaukee is doing exactly what should be done, its certainly telling the the Mercedes dealer doesn't want to touch it.

The only plausible path I can see to providing a fix is to find another E300D that runs correctly and start swapping (one at a time) wiring harnesses, ECU and then the actual IDI injection pump. I'm not 100% sure of cars of this vintage but the ECU swap might also involve the EIS key and the steering column lock.

You could certainly disassemble things and look for cold solder joints or fractures in circuit boards and wires in the harness but this is, to say the least, a needle-in-the-haystack kind of task and if the issue is actually a problem related to a capacitor or a transistor that drives the rack position motor you'll never find it with a visual inspection. At least with the needle-in-a-haystack metaphor there is a needle to be found with a visual inspection of the haystack.

If you're paying a competent professional mechanic to do this sort of work you're going to exceed the value of the car in about 3 days. It would all have to be time and materials work with no guarantee of success.

Sorry..... but that's all I've got.

If you decide to throw in the towel there is one other thing you should be aware of - the OM606 turbo is a very popular engine for engine swap projects. It can be easily retrofitted with a fully mechanical pump from and OM603 and make huge HP. There are aftermarket companies that provide tuning, performance upgrades and transmission adaptors and its very much in demand. Not sure what they're selling for but I see lower mileage examples frequently listed for 3-4K dollars. Someone that was going to swap a mechanical pump wouldn't care if the current computer controlled system was flakey. Don't sell the car for trade-in value if you decide to move on.