Well, fool that I am it turns out that in the haste of the on-the-road repair attempt I had jumpered the wrong two pins on the fuel pump/kickdown relay. (Pin 87k is not the same as pin 87.) When I jumpered the correct two pins the pump ran. (That would have made getting it home a lot easier!) On the plus side, this mistake did cause me to take apart the connections on the fuel pump, for which the protective boots were all torn up. I taped up the boots and potted them in Shoe Goo, this should help keep the water out of these connections.
Anyway, I put the relay on the bench and it didn't feed power to the pump output unless the start pin was asserted. It might be supposed to give it a burp of a second or so at key-on as well, though I only infer this from the 560 SLs' behaviors. (And obviously it also didn't feed power when the engine is running.) I opened it up to find the usual sort of vintage circuit: two CMOS 4013 dual-D flip-flops, two 555 timers, four transistors, nine diodes, two electrolytic capacitors, two trim pots, one thermistor, two relays, and the usual handful of resistors and capacitors. Highly repairable, in other words. The solder was starting to look a little oxidized, I suspect that this thing will succumb to a resoldering. The relay box is labeled with "5300/min 8Zyl.12V", a Bosch logo and "896377", "Kickdown", and has what looks like a date code on it: 27-02-1997. If so this certainly isn't the original! And if so, isn't much of an advertisement for Bosch electrical part longevity. So I resoldered it, first giving it a good wire-brushing with the Dremel to remove oxidation. When reinstalled in the car, it started and ran. That's $155 I don't need to spend! (The fuel pump, also unnecessary, is $250.) There was still no key-on burp, so I guess that's a feature of later cars. I then cleaned off the differential fill plug and removed it. (It has a non-factory gasket on it, and the plug has been chiseled, though the hex socket is still in good shape.) The oil was low, but not dangerously so. I put in 1/2 quart and put the plug back in, lowered the car, and took it for a little test drive. It drove well, the engine and transmission seemed as it should, the brakes worked well. (Perhaps not perfectly, it did pull a bit.) It seemed to have the requisite amount of power for the 3.8l motor, though I've no prior experience with them. There was some rattling from the RF corner of the car on the gravel washboard, there may be some loose suspension. I'll have a look at that sometime. I tried the cruise and it didn't work, though I recall the PO saying something about that it should be disconnected because he thought it could self-destruct trying to use it when it was flakey. It may be unplugged somewhere. -- Jim _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
