W116032 450 SE USA Benzin in Öl

Hi Norbert,

not sure whether I remember correctly that I verified the ECU. But could well be.

Hello again,
Reopening this topic after several years of happy driving my 450SE with zero issues (thanks to Volker!).

Unfortunately new problem developed quite recently. One morning when I started the car I observed engine was running quite unstable, despite previous flawless operation. I drove the car for one km (dropping the kids to school), engine was apparently running rich. Stopped the car, started again but with extreme difficulty. I went back home (with quite problems), parked the car and since then I was not able  to start it again - flooded with petrol. I literally heard the fuel flowing to cylinders. Oil changed, new battery installed, problem still present.

So we moved the car to Petr’s repair shop. And here is the observation:
When the ignition Is switched on, all injectors are open immediately, not even when cranking the engine. Ignition key switch to on, Fuel pump is switched on and priming the circuit and petrol is just spraying out of all 8 injectors ( observed when we removed injectors with rails and left them sitting on engine). Unfortunately this happens randomly, not every time....some occasions the startup is as it should be. Trigger contacts checked, no sticking or other issues.

any thoughts or similar experience?

thanks a lot for any comments or ideas. We will continue with further checks next week. BR Petr
 

Hi Petr,
I remember you well and think I bypassed your shop by car some years ago...

About the problem you have now:
Could you please read out the voltage at the injectors? It seems they are powered in bypassing the ECU... injecting all at the same time... 

Best Regards
Norbert

Hi Petr,
does fule pump run all the time after igntion is switched on without starting engine. Same for all 8 injectors?

If that is the case, either you have a wiring harness shortcut or unfortunately ECU has an issue. If it is all 8 injectors and fuel pump running I fear it looks like an ECU failure.

Hi Norbert, Volker,
we will measure everything tomorrow.

the fuel pump runs correctly, couple of seconds and cuts off. Injectors are open, all 8, and spray until pressure decreases. no cranking, just ignition on in second position. The fault is random, sometimes everything is ok, and engine runs. We were lucky we spotted it when injectors left outside the engine...it was like a fountain, all 8 together

Our suspicion is also ecu, in this case, unfortunately. 

Rgds Petr

Hi Petr,

if it was a shortcut, it would have to be to pins 3, 4, 5, and 6. Possible but not very probable. You might remove ECU connector and try without ECU what happens.