We are having a spin and no start condition with our 93 960- We were replacing the windshield wiper cowl panel, and had it off, and the battery died after sitting up for a few days. Still do not know why the battery dies. We have a freshly rebuilt ECU, along with a known good ECU, a new fuel pump relay, along with a relay that I personally rebuilt. When we turn the key, the fuel pump relay will not run, but, I can pull the cap off of the relay, and manually actuate it and make the pump run. We also have an adjustable Kirban Fuel Pressure Regulator that I set up the plumbing for. Are there any glaring or obvious things that I should check?

 

i am more of a porsche/BMW guy, but i see no one has helped.

with most cars, when you turn the key from off to on, the FP will run for 2-3 seconds to prime, then it shuts off. once the engine fires, the ECU, or even the AFM on some cars, will turn on the FP.

since you can make the FP run, run the pump and try to start the car. this will eliminate a lot of things that can be wrong. if it still does not start, your problem may be elsewhere. i would start with the CPS.

if the battery was not connected, the battery is bad. have it checked at advance to make sure.
if it was connected, you have a drain.

dissconnect the neg side of the battery. connect a test light (TL) between the cable and the battery. if it lights, you have a drain. open a door or turn on a light, and it should light if it did not.

with all doors closed and everything off, remove fuses one at a time until the light goes out.

if you need any 93 or 95 parts, let me know.
843 222 1537

 

Thanks for the help 1977 911 Targa, I believe it is C2, the large black connector over the US Drivers left foot, that had been taken apart, but not fully reconnected, and it had a ty wrap/zip tie holding it together, and when I wiggled it, the ECU would drop the signal to the fuel pump relay. So I cut the tie, plugged and unplugged the connector several times, and that seemed to cure it! has been running good for a few weeks now! I am a Ford fan, but Mercedes trained, and it always leads me back to the wiring diagrams... One of my mantras is- "Check the Grounds...." Another is "Check the wires around the engine...."

 

MERCEDES! awesome. i have an 00 e320, i WILL need someone to talk to with this one.
incredible cars! , well, automobiles as someone once corrected me.
the AC fan stopped working. i was thinking it was the resistor pack. i pulled the fan and could not get it to work on the bench. so i blew some of the dust out of the samll hole in the housing and then pushed the brush block up againts the motor and it fired up. been working ever since.