llebyat

Hi
I have just bought a 1987 300se W126 and all had been fine for the 1st day!

Then suddenly when turning a corner at low speed the car just spluttered and maybe was missing then all was ok. This is now happening all the time at low speeds (ie juctions etc) with total loss for power and spluttering and then it just recovers. Its just as if theres a bad connection on someting for a few seconds.

Any ideas

Thanks a lot

hineywineries

Buddy,
Your question requires someone with a crystal ball. It could be anything at this point. You've got an intermittent. an intermittent is a mechanic's worst nightmare. I'll give you a couple of suggestions. Here is a list of components that might be failing: Fuel pump, fuel pump relay, OVP relay, ignition rotor, or the EZL module. You can unplug the ECU ( main computer) with the key off.You can drive the car this way and see if the problem still exists. This will isolate some circuits.
Good luck

BENZITCH

Choosing from your list, I'd say fuel pump relay, is the most likely suspect.

hineywineries

I have dealt with every item on the list, but fuel pump relay would be the easiest to eliminate by jumpering it. That would br a good place to start.

llebyat

Hi
Thanks for your help

Someboby who says he's a merc expert has suggested that a temp sensor on the top of the engine towards the rear is either faulty or has a bad connection and is telling the ecu that the engine is cold and over fueling it?

Don't seem right to me?

Anyone heard of that one?

Thanks

luda

I had the same problem on my 89, 300SE. Normally at high speed turning into a left turn. (Yes, sounds crazy). Later it would appear in any situation, it basically just died.
Not saying that it could not be in your case, but I changed all parts mentioned above. Even changed the cable from the pump to the reley.
It could of cause be a combination of several faults.
In my case it turned out to be a small brass valve/filter located at the fuel inlet to the injection system.

No problems since 2 years.

hineywineries

That's why I suggested unplugging the ECU. This will put you back to basic CIS. It takes temp sensors and O2 fuel trim out of the picture. You can jumper the fuel pump relay and eliminate it without buying one if it's not the problem.

tbjcc001

I'm having the same problem presently with my 420sel! Can you provide specifics on this procedure.....

hineywineries

Which problem?

tbjcc001

Jumping the relay for the fuel pump........

tbjcc001

My fuel pumps & filter are new as of Jan. 08. I believe I need a a new Idle Control Unit, Valve & OVP because I have a erratic idle condition & have checked foe & corrected a few vacuum problems. However, presently my main concern is that I shutoff when I release the accelerator, ie red lights..

Cap, Rotor, Plugs & Wires new
Pumps New
OPV Fuse (10 Amp) new

1986 420sel 188k