Today my E320 wagon developed what I think is a miss when accelerating from a stop. When it happens, the car will just not go; when the accerlator is pressed, the engine seems to stop. When I let up on the accerator, the car idles and creeps forward just fine. I can make the problem temporarily go away by shifting into reverse, and then into drive again. A few miles later the problem re-occurs.

Car has 125k miles. I installed a new OVP 6 months ago from dealer becuase the car would not start. It has the updated part number (the old one did as well). Is it possible that the new OVP is defective? I cannot determine if the wiring harness has been replaced; I've cut it open at the valve cover; it's definitely stiff, but the insulation is not broken. No check engine light or codes. Anyone have any other suggestions? Otherwise, I guess I will see if the dealer will replace the OVP on warranty and then perhaps spring for a harness. Thanks much.

__________________
as ever
Paul

1989 560SL
1987 300SDL
1987 300TD
1983 BMW 633CSi
1972 280SE 4.5

Why would you seek warrantee on a part you have no concept of problems on?

I would presume all aspects of life are a little more expensive due to such logic and the acceptance of some retailers to just go along. If you actually have a problem with the part it should be warranteed. I consider presenting it as failed with no such info, as petty theft.

Besides that an OVP on a 95 E320 can cause a no start, but would be about impossible to cause a misfire. The device is a power supply. The control units that need it work or don't when they don't get power. The early cars didn't need the electronics to run so a bad OVP could cause a running problem, not so with your car.

More likely, are the coils or coil to plug connectors. Those connectors are cheap enough to just replace all three of them (one to each of three coils).

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

There's lots of things it could be. You need to read the fault codes or get them read somewhere. The part number on the wiring harness will tell you if it's original (bad) or a replacement (good). Not a good idea to be cutting it open.

Thanks for the comments, folks; I've already replaced the 3 coil to plug connectors in the past 12 months when one of the coils failed with code 22.

Maybe a miss is the wrong description; is more like the engine completely cuts out when the problem occurs. Acceralator floored and nothing happens, like someone turned off the key. This is why I suspected OVP. I will monitor power after the relay to debug.

I'll check pin 8 once again for codes.

Thanks.

__________________
as ever
Paul

1989 560SL
1987 300SDL
1987 300TD
1983 BMW 633CSi
1972 280SE 4.5

Sounds like your mass air meter. Thats what my car was doing, or so I thought. You can remove the wiring to the mass air meter and the car will still run. See if it still does the same thing while its removed(you can drive the car with out it for a long time, just doesnt run as efficiently). I replaced mine twice and then realized it was the engine wiring harness causing the problem. Hope this helps.
Chris

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94 E320 with:
18" ///AMG Monoblock II's,AMG Gen II front bumper, H&R spings,500E sway bar, Bilstein sports, Eisemann Exhst, K&N,E500 Headlamps, Crystal Clear Corners, Avantgard Grill ...and more stuff to come! oh yeah 241k miles!!


My Car WOO HOO...... Now SOLD
New car.... 2001 Jaguar XJR!!!!

A side note: check your plugs too. If the electrode is too worn your gap can go from 0.032 to 0.048 (like mine did) and cause this type of problem under load. Make sure they are Bosch F8DC4. What happend to 'total' all those cars?

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles

After driving around the block many times, I am now able to pull code 45 from HFM pin 8. The text I found code is "Fuel safety shut-off of electronic accelerator or cruise control active". This code does seem to correlate with the behavior, I think.

The car des not have ASR or electronic accelerator, but does have cruise.

__________________
as ever
Paul

1989 560SL
1987 300SDL
1987 300TD
1983 BMW 633CSi
1972 280SE 4.5

May have something to do with your throttle body actuator or your wiring harness or both, but I revert to that since I had a multitude of problems before I replaced both and now I have been trouble free since then(knock on wood! ) I have 240k miles on my car and its going strong!!
Chris

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94 E320 with:
18" ///AMG Monoblock II's,AMG Gen II front bumper, H&R spings,500E sway bar, Bilstein sports, Eisemann Exhst, K&N,E500 Headlamps, Crystal Clear Corners, Avantgard Grill ...and more stuff to come! oh yeah 241k miles!!


My Car WOO HOO...... Now SOLD
New car.... 2001 Jaguar XJR!!!!

Check for codes on pin 14 CC/ISC if you don't have EA. Sounds like a throttle assy type of problem.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Ah, on pin 14

5 Stop lamp switch
and
11 Fuel safety shut-off to LH-SFI control module

Could it be as simple as the brake light switch? I'll have to dig into tonight.

Thanks again for the help thus far.

__________________
as ever
Paul

1989 560SL
1987 300SDL
1987 300TD
1983 BMW 633CSi
1972 280SE 4.5

Fuel Pump Relay are known weak area's on this model. This relay costs about $20. Location next to the AC compressor relay, green in color. In the general area of the battery.

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Zafar
94 E320 58000 Miles

Yes, stop light switch, very common problem.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Have you checked your fuel pressure? When was the last time that you changed the fuel filter?

Good luck,

I replaced the stop lamp switch; I think it was bad as one set of contacts was permanently open.

Before I put the switch in, I started the car to move it; at this time the idle was up and down between 500 and 1500 and the engine would not go any faster than this. After I installed the switch, behavior was basically same, but gradually cleared up as I let it run, although I don't think the car has 100% power, yet. I cleared all the codes from pins 8 and 14 (there was an additional code on pin 8, code 8 which is related to the idle speed/cc device) and drove around the block. No codes came back, yet....

How does the car "know" that the stop light switch is fixed? Is it by clearing the codes, or does the car have to be driven a bit?

__________________
as ever
Paul

1989 560SL
1987 300SDL
1987 300TD
1983 BMW 633CSi
1972 280SE 4.5

A final update on this problem: the car continued to have low power, poor cold starts, random cut-outs when accelerating, and the A/C stopped working; I happened to to be using my multi-meter at the diag socket to remind myself of the polarity noticed that with the car idling, I was getting 18v! I replaced the voltage regulator on the alternator and everything is back to normal.

This is something I would have never suspected.

__________________
as ever
Paul

1989 560SL
1987 300SDL
1987 300TD
1983 BMW 633CSi
1972 280SE 4.5