Hello, on 1.9L, 2 main thing that influence "Idle" is the throttle body (bad
seal to air plenium, loose/worn T-plate, switch position) and a bad timming
or worn distributor.

Also, of what i can see, you may have a bad connection at one injector (on
and off).

Ben

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The Conflict: Lately, the idle on my 84 1.9 has been dropping down to almost
zero, then back up, then to 250 or so, then back up. I've checked and
repaired all the engine systems extensively, except for the Hall sender (I
can't figure out a way to turn the crankshaft by myself.) Everything checks
out, including coil, all ECU pins, new grounds everywhere, new O2 sensor,
new Temp 2 sensor, rebuilt AFM, AAR, fuel pressure regulator and pump and
filter and gas lines...all good...

The question: Could this intermittent idle problem be caused by the Hall sender?

The clue: About three months ago, I replaced the rotor with one NOT coded
for Hall sensor vehicles, as I wasn't aware there was a difference. (The
rotor is to Bentley specs ohm-wise.) Could the wrong rotor take out a Hall
sender?

The red herring? Also, maybe unrelated, the van suddenly started running on
three cylinders; a voltage check at the #1 injector indicated a bad ECU;
swapped out and it runs ok again. Could the bad rotor (if it is bad) kill an
otherwise good ECU?

Thanks for any ideas on this one. I'm not driving the van until this is
fixed as I don't want to disturb anything else in the ignition system, like
blow my good ECU...