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  Topic Review (Newest First)
07-28-2019 02:25 PM
pt_700 mr boca helps another! we are fortunate to have many like him here.

please never leave this forum, ha ha!
07-28-2019 02:15 PM
bluerooster Replacement installed Friday, drove it yesterday, and today. No issues.
07-21-2019 03:26 PM
mrboca It is a common problem with the relays (either the fuel pump relay or the relay that powers the ECU. It is best to get a replacement.
07-21-2019 02:42 PM
bluerooster The K40 for the 420 is a bit different, but I figure that it operates the same.

There is full time "hot" to the coil of the K1 via pin A2, the ECM provides "earth" to engage the K1. K1 will not engage when grounded at the proper pin (E3). I figure that the relay, or connection between relay and pin E3 is bad.
07-20-2019 03:08 PM
mrboca defs
07-20-2019 03:06 PM
mrboca You could try the following. This is for 1997 E320 but should be the same or similar. Obviously either the K1 is bad or the ECU is not turning it on for some reason.
07-20-2019 02:28 PM
bluerooster Fuel pump had been running up until today, now it only runs when I manually engage K1. So now I need to look "upstream" to find what tells K1 to engage, and see if there is signal from that point.
07-20-2019 01:12 PM
mrboca The diagram is incorrect in that sense, but if the fuel pump runs, that is not what you need to worry about. Check the voltage on the camshaft timing solenoids and the air pump switchover pump terminals with the key is position 2.
07-20-2019 12:39 PM
bluerooster Interesting, that the fuel pump is not powered directly from the fuel pump relay in the K40 box. Based upon the schematic that you posted.
06-16-2019 03:02 PM
Originally Posted by bluerooster View Post
Checking K40 is where I found the bad connection. (see previous post )

I'll be testing individual components later, after it cools. (of course they all will be fine, untill warm again )

I'll get it sussed, one day. And as my luck goes, it will be something as simple as a mouse chewed a wire, causing an intermittant connection, and all sorts of crazy stuff.
Just follow the lines from the camshaft solenoids + air pump switchover valve on the right top of the diagram. Can you see that they are all powered by the same line, fuse, and relay ? And check the ground connections. Especially the relay that powers them all.
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