Jill's been having persistent starting troubles on the Chicken Wagon, but all the GP's are (now) good. It cranks just fine, but won't start. Intermittently, according to her. To me it sounds like the GP's just aren't doing their job well. Today I had a chance to dig into it a little bit. I started by cleaning the relay connections and putting Caig Deoxit on them. I pulled the big fuse and it was good, but I still cleaned it off with a little wire brush and put it back together with Deoxit. I pulled the relay and took it to the bench, but it seemed to behave well there. (Interestingly, if the big fuse is not there the relay will buzz loudly after it times out, I wonder if that is deliberate? I'll look into that further later, it may be one of the system's self-diagnostic traits.) Back on the car I checked the GP current, it started out at a peak of 130A and dropped down to about 50A steady-state. The GP's, however, were only getting at most 10V on them. I measured 0.2V drop on ground side of battery to the engine block, which was good. Between the battery positive post to the relay power post I measured a 2V drop while the GP's were on, that's terrible! She had to go so I didn't get to dig into it further, but I imagine that either the feed end of the power wire to the relay is corroded or loose, or else the wire itself has been damaged somehow. I checked the ETM and found that C105 is where this wire supposedly originates, and that this is the three-terminal power block right next to the battery. I'd already loosened and tightened its three screws, and sprayed Deoxit on them, as part of what I'd first done, but nothing more. Next time.
The car started beautifully, of course, but I'd had the block heater on while I was working on it, and of course the glow plugs had gotten run a fair bit while sleuthing. (The battery charger was on it all the time, to replenish the losses.) And it was parked inside. I _expected_ no trouble this time. -- Jim _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
