PeachParts Mercedes-Benz Forum - View Single Post - 1975 Mercedes 450 SLC, Model 107

Tomguy · #12 08-06-2007, 09:22 PM

Well, as I said, if you were getting gas out of them you'd be flooded after all this cranking, but since you're not getting gas:
You said you heard the injectors clicking. This sounds like they're opening, but all plugged up. Yes, all can plug up; and it's possible whatever is plugging them is causing your regulator to malfunction (see addendum below). So your ECU isn't the issue. If you want to make sure an individual injector is getting power (just as a test), put an LED on the wire and crank; if it doesn't flash reverse it and try again. No pulse from the LED would indicate failure (maybe use an LED that also helps determine polarity, but brown is ground. I suggest an LED because you should be able to see that strobe, a bulb may not be as obvious). Pull an injector off, clean it out by squirting carb cleaner into the top and see what crud comes out. Soak them overnight in carb cleaner if need be. Test to see if it opens (WHEN IT IS DRY!) by giving it 12V, polarity doesn't matter; it should open.

Also: You definitely need a new regulator. Although you should be able to start... my fuel rails can hold the 30PSI required for a LONG time.