Hello, everyone. This is my first post on this forum.
I appreciate all parties' willingness to share knowledge.

I hope someone may be able to assist me...

I have owned a 1993 Mercedes Benz 500E since March, 1998.

Since approximately January of 1999, it has exhibited the following, dangerous behavior/condition:

- when making sharp left or right turns and/or going up or down spiraling parking garage access ramps, my engine cuts out/dies

Sadly, my local Mercedes dealership has proven to be both reluctant and, ultimately, incapable of diagnosing and fixing my problem! I first reported the problem over 6 months ago! Since then, my vehicle has been in and out of the shop, to my great frustration. Chemical additives were even introduced to my fuel system to attempt to raise the idle speed - with zero success. Again, absolutely nothing has fixed the problem. I find this situation both unacceptable, incomprehensible, and frustrating - not to mention very dangerous!

The only modifications in my vehicle follow:

- RENNTech ASR defeat switch (relay)
- BRABUS sport steering wheel and airbag
- Precision Auto Design (LH unit) performance chip
- Precision Auto Design airbox w/high-flow K&N air filters
- AMG rear silencer (AMG part # HWA-124-490-1721)
- 18" AMG Monoblock Aero II wheels w/Dunlop P9000 tires

The only additional data I can provide is:
- my idle speed (at rest) is below 500 RPM (480-495 RPM)
- my vehicle has been running Mobil-1 since 1996

I have all new fuel-related electronics (E-GAS, etc.), a new throttle body actuator and a new fuel pump. My vehicle is (otherwise) in excellent working order (needless to say, I keep it immaculate). My odometer currently reads 87,000 miles. I have had all scheduled (dealer) maintenance performed, without exception.

I believe different production years of the 500E/E500 vary, in BHP; if so, do they also vary in (at rest) idle speed? What should my idle speed be while in "Drive"
(not in "P," as the rate would increase, obviously), please? Can any other 1993 500E owners provide any data?

Any/all advice you might provide will be MOST appreciated; thank you very much, in advance, for your prompt reply.

With kind regards,

I recall seeing a similar condition in the records of my 500E. I am not the original owner.

The PO described the condition as "Cutting out and loosing power when going up hill and cornering". The dealer found a code stored in the computer for a Brake Switch.

The experts may have some insight?

Tracy:

Thank you for your prompt reply.

Please allow me to clarify, per your posted questions
(your comments are annotated with 2 greater-than signs):

>>How far does it die?
It cuts out, completely, to "dead-in-place" mode.

>>Do you have to re-start it?
Yes, every time.

>>Does it backfire?
No, never.

>>Has anyone checked for solid connection of the coil, ground to frame, starter motor, and battery?
Yes; no error condition exists (my mechanic/tech says).

>>Have you replaced the spark plug and coil wires?
No; they show no signs of excessive wear/corrosion.

>>Does it do this if most or all of the unessential electrical components (a/c hifi, lights, seat heaters, blinkers etc) are off? Do you ever blow any fuses as a result of this?
Yes. The problem occurs, repeatably, at all times of the day/night, at all environmnetal temperatures, rain or shine, indoors (parking gargae) or outside, and always as a result of surging acceleration (rev-rev-rev) - followed by total loss of engine power. Note: electrical power to the vehicle's components does NOT disconnect/cycle/dim, at all.

I am most mystified by the fact that this only occurs when sharp turns (at low speeds) are made, when idle RPM is low!

Any more insight (anyone)???

Kind regards,

- Scott M. Shell

Tracy:

My vehicle has always been in Northern California, inland, removed from corrosive salt air and/or cold weather variables.

I will discuss your ignition contact hypothesis with my technician, ASAP; however, (some additional data, here), the last time my 500E was at the dealership for service, Mercedes Benz (purportedly) had sent a senior technician from New Jersey (I was never given his name) who claimed that "no reproducible problem exists." When I went to pick up my vehicle, that night - and demonstrate the problem, first-hand - he was nowhere to be found. I never met him!

THAT seemed more than a bit fishy to say the least.

Thank you for your time and insight,

You failed to mention the wiring harness... do you know if it has been replaced?

__________________
Mark Herzig
1995 E300D 153K
1985 300D 142K (sold)
1979 450SL 122 miles (sold)
1992 500E 127K (sold)
1987 300SDL 132K (sold)
1986 300E 161K (sold)

Mark:

One of my wiring harnesses has, indeed been replaced (3 weeks ago); it is my understanding that there are 2 wiring harnesses:
- wiring harness #1 = under the valve cover
- wiring harness #2 = connects with the alternator

Truthfully, I do not know which was replaced.
I will ask my technician to clarify.

I am perplexed as to why this problem evinces itself
only when the vehicle is making low speed, sharp turns. I realize that there are increased loads placed upon the engine under such circumstances - but no one has yet to address whether or not my idle speed is uncharacteristically low:

Again, my idle speed (at rest/near rest) is approximately 480 to 495 RPM.

To clarify, when I rev up the engine, while turning (by accelerating more aggressively), the resultant, higher RPM defeats the stalling problem. It is only when I turn with normal acceleration that the vehicle surges (surge-surge-surge, during which the tach needle wobbles between mid-400 level and not-quite 500 RPM) and stalls.

I would like to ask other 19993 500E owners what their respective idle speeds are. Any/all input in this "survey" would prove to be invaluable to my research efforts.

As ever (with sincere appreciation),

WHen the engine is cold, it idles over 1000 and after about 20 seconds, settles down to 800 or so where it idles for the remainder of the drive.

I had some stalling upon startup but replacing the TBA fixed that. I wonder if you have an electrical shorting issue that is physically realized when you turn sharply (is it direction related? only left turns? ) the electronic ignition shorts out.

__________________
Mark Herzig
1995 E300D 153K
1985 300D 142K (sold)
1979 450SL 122 miles (sold)
1992 500E 127K (sold)
1987 300SDL 132K (sold)
1986 300E 161K (sold)

After thinking more about this. I have seen a condition where this was happening when the A/C was on and the auxillary fans were not operational. The fuse likes to blow and the resistor will blow out. When this happens the fans do not work and the system pressure is high, thus causing stress on the engine. (Just a thought.)

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

Mark:

Thank you for your idle-speed data. It seems to be a consensus that my idle speed is VERY low. I received e-mail from RENNtech, which concurs.

I will ask my technician, later this week, about your and Benzmac's (Donnie's) replies.

Kind regards,

Donnie:

Thank you for taking extra time to brainstorm. I most appreciate your suggestion/hypothesis. Are you saying that
I should try the same test with the A/C off? If so, will that cause the fans to remain on, thereby cooling the engine and reducing load? It's certainly worth a try: I will let you know the results.

I forgot to mention, in my last reply to Mark Herzig, that
the stalling condition is reproducible in either right *OR* left U-turns/severe turns. Apparently, the problem is NOT directional in nature, which leads me to conclude that it must not be wiring-harness related (???) I may be wrong...

I am compiling a list of everyone's suggestions, which I
will present to my service technician, by Friday.

Kind regards,

I'm just stabbing in the dark, but is this at full wheel lock?

Maybe power steering pump is contributing too much strain?

[Edited by roas on 03-13-2001 at 12:39 AM]

My vehicle stalls both at "full steering wheel lock" and
"near steering wheel lock," for what that may be worth.
I just confirmed this, earlier this afternoon.

I appreciate your thoughts - thank you. I have added them to my list of possible fixes.

I will keep you and everyone else posted as to my progress.

Sincerely,

My records for my 500E also show something like this...stalling and a replaced wiring harness under warrantee. Maybe your second wiring harness? I does sound like a loose electrical connection of some kind. Good luck!

I will look into this solution, along with the recommendation that I consider diagnosing/replacing my power steering pump.

I appreciate your comments; thank you for your time.

Best wishes to you,

Hi Scott, dont know if this helps, but I have posted a thread regarding stalls (see below). I have the same problem too, so I know exactly how you feel. Its both exasperating and worrysome, as this phenomena has dozens of possible causes. You might want to check your ignition control module, it sounds highly suspicious.

All the best!

Mervyn


Here's something to share with all MB owners. Recently I'd gone thru a frustrating experience with intermittent stalls, especially when the car is coming to a slow, say at a traffic junction or a bend, and it stalls. Subsequent starts then become more difficult, taking more cranks than usual. And at times, it stalls again right after it got fired up. I've gone thru practically all the threads in this forum (as well as other forums on other makes), and there are really a dozen of possible causes out there. Trust me. In cases like mine where the availability of good and proper diagnostic specialists and equipment is rare, this forum is where it matters. For my case, while my mechanic can only second-guess what causes the problem, at least I can reaffirm it. So guys, if you have a problem and you think you need second and third opinions, go do a search in this forum. Or at best, post a new topic.

Ok, lets get to the point. If you experience the above problems, start by checking these 2 parts:
1. Idle Control Valve/Idle Speed Stabilizer
2. Ignition Control Module

These are the parts that I replaced, and the stalling's gone. It aint really cheap, but they do look way past their time and I feel better changing them. The idle control valve especially, you should see the amount of deposits and gunk on it, its way disgusting!

The car feels like it has a fresh new life now.

Other very possible causes are:
3. Fuel Pump Relay (and perhaps other related relays)
4. Distributor Cap and Rotor (inexpensive replacement)
5. Ignition Coil (inexpensive replacement)
6. Vacumm hose clogged/leaked

My conclusion is that for stalling problems, usually it is either the ignition system or the idle control components, or both. I would advise that if you know your cap and rotors,plug wires, plugs, are old, change them first. And then further diagnose the problem. No point chasing after problems which could in fact be attributed by old parts which naturally could not perform due to wear-and-tear.

Of course there are other causes relating to a stalling problem, but those that I'd highlighted here are at best peculiar to my own. Hope the info is useful.

Mervyn
1983 W126 (280 SEL)