1989 Mercedes 190E 2.6......Fuel Pumps running fine and suddenly die.

[ashevillemerc]

Just purchased this car from a man, it had been sitting awhile, It needs some TLC but the problem I am having with it is that the car will run for approx 30 sec. Then just die. I first looked at the fuel pump relay crossed it so it runs all the time and the issue is still there. I had a buddy start the car for me and I got under it at the fuel pumps with a test light, after the car runs its approx 30 sec all my voltage at the fuel pumps drops and I have no juice at the pumps. The strange thing is that once the car dies, it will start right back up and run again for around 30 sec. It starts right back everytime and everytime after that 30 sec period I again and again lose all power to my fuel pumps. All while my fuel pump relay has been crossed. What other parts should I look at that could be the culprit in my fuel pumps loosing their juice.

[sakeel1234]

My '89 300SEL has same symptoms and only runs 2-3 seconds. Help!!

[sakeel1234]

When I turn the key to start my tach jumps up and then drops right back down to zero. The engine responds to the accelerator a couple of times during the 2 second run. Please point me in the right direction to diagnose this opportunity.

[ashevillemerc]

Your problem sounds like it is a good chance it may be the fuel pump relay. You need to check to see if your getting fuel and spark that will get you in the direction you need to go.

Anyone have any suggestions on my particular problems?

[sptt]

Sounds simple stupid but have you checked your fuse box? Carefully spin the fuses around to make sure they are making good contact if you haven't already. That way you know it is an actual component. Also, does anyone think this could be an OVP possibility?

[Holmesuser01]

If you cant get it straightened out, there is a shop in Candler NC that does Mercedes work. He's good, and has straightened my 1984 190E right out with me.

They were working on a 190E on Friday that had been sitting for awhile. Someone had painted the valve cover blue! They were busy with a new water pump while I was there.

[sptt]

...Also, my daughter's 300E was doing that and I wiggled and wedged the relays in nice and tight and it stopped.

[my83300cd]

Try pulling out the fuel pump relay and the OVP (with the fuses on the top) next to it. Clean/vacum accumulated debris out of the area and try re installing. Check the fuses on the OVP while you are at it

[sakeel1234]

1989 300SEL Engine/Motor #103981 12 070224.
When I try to start the car it will run for a couple of seconds and the stops. When this first started the tachometer would jump up and then settled back at zero. Now it no longer gets off zero. I have done the following tests:
Continuity from CIS-E pin #25 to Fuel pump relay pin #10 to A/C Klima relay #2 to X11 pin 1 to Crank Position sensor #31 all checks out.
The fuel pumps are cutting out after a couple of seconds. Apparently no TD Signal.
If I jumper Fuel Relay Pins 7 & 8 the car will run.
Checking voltage while the car is running at X11 between pins #2 and #3 and get 6.1 AC volts.
Crankshaft position sensor from #7 to #31 has 871 Ohms.
Problem comes here..
Jumper Fuel Pump #7 and #8, Turn the ignition from Fuel Pump Relay pin #9 to #11 get Battery Voltage.
However from Fuel Pump #10 to #11 NOTHING.
Could a bad Tachometer be my problem?

I have another symptom/problem...My Fuse/Relay Box has a special label under Relays "C" and "D" designating them as "CC" and "DD".
There is no Relay "F" just a hole. And if I leave relay "I" in the power to my windshield wipers and radio doesn't go off when I turn the key off.
If I put it in and don't turn the key all is well, but as soon as I turn the key relay "I" locks in and stays energized. The only way to stop the radio and wipers power is to pull the relay. HELP PLEASE