Quote:
Originally Posted by Benz124s
Hi All,
The car I am working on is a 1987 420 SEL as the thread title suggests. Recently, I had the fuel distributor professionally rebuilt. It came with instructions saying to adjust the fuel mixture with the 3mm hex screw with the engine fully warm. I hooked up my digital meter set to read mA (was looking for a reading of around 1-3 mA as indicated in the instructions sent with the rebuilt FD). Upon doing this I cannot get any reading on my meter with the car idling and the leads connected to the EHA harness (connecting into the wire closest to the FD). Why would this be? I already tried replacing the OVP relay with a new one thinking that would power the EHA, but that didn't make a difference. Where does the EHA get power from?
Thanks in advance,
Dave
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To answer your second question first; the EHA is driven by the engine control unit (ECU).
Re: Test lead connections
The leads must be in series with one of the two wires connected to the EHA, rather than across both of the wires, which would be a parallel connection. To do this, a jumper is placed between harness and EHA on one leg, and the meter leads connected to the remaining pin and socket. If connected in series, good. In that case, the absence of a current points to the ECU, or the wiring itself.