Ωhm

I wonder what that means. Offset CPS???? Different ECU???? Different CCV????

Sounds like you nailed it, faulty switch.

Welcome to CC Forum.

HI/LOW speed is pretty straight forward to the motor. PARK is a make/break switch depending on the position of motor rotation. Note B+ can only pass when the PARK switch is in a 'make' position and the Wiper Switch is in the OFF position. This will drive the motor (LO) until the PARK switch is in the 'break' position. This should add to the confusion. Hope you figure it out.

https://comancheclub.com/topic/12083-electrical-manual/ Wiper Motors have a PARK (the wipers) circuit.

When TS don't work, do the following components work: Blower Motor, Wiper/Washer Motor, Radio

O2S only read oxygen in the exhaust gas. 14.7:1 is O2S voltage of 2.5v.

Units used for pressure are in PSI.

I'll remember that. Good tip there.

May have to compare TPS(%) with actual TPS (v) using a voltmeter. Use cruisers tip adjustment procedure. High Idle may also mean your sucking air somewhere. Possible faulty O2S (slow or NO response).

Idle RPM's seem high (900). Does the EXHAUST PID switch between LEAN and RICH rapidly (close to the speed of light)? Does O2S voltage switch between 0.2v and 4.95v rapidly? OPEN LOOP will not change FUEL TRIM values. I'll take it that 5% for TPS is correct.

If you can't fix it with a hammer, you've got an electrical problem.

I'm sure they paid 'dearly'.

Alliance: Motor Trend's "Car of the Year" 1983.

Check MAP hose. Can you keep engine running with a spray can of starting fluid?

Download the 88 Electrical Manual to your hard drive. Your 1986 will have 99% of the 1988. Helps explain Connector numbers and Cavities callouts. Allows everyone to be on the same page. https://comancheclub.com/topic/12083-electrical-manual/ Also, when checking connectors, check where the wire meets the terminal. Can be a problem area.

CC Forum is a great place for solving problems, just remember sometimes your questions are answered with more questions. This style of testing is more of a continuity check from one end of a wire to the other end. You showed this wire is good from end to other end. With everything connected, except the wire at the sending unit, your reading of 6v maybe a good reading. You need to know if your cluster is grounded properly. Need a ohmmeter.

I'll take that to mean the plus side of the voltmeter. I'll take that to mean the negative side of the voltmeter was ground near the sending unit and not the sending unit wire. If this circuit with firewall connector (C100) disconnected, should not have 12v on it. If so, does it have 12v with both the KEY OFF and the KEY ON?

I don't get the increase in voltage between firewall and cluster (6v) to between firewall and sending unit (12v). Should be the same wire. Need four (4) measurement on the same connector. Disconnect C105, on the Engine Harness side, measure voltage at C105_B with both the KEY OFF and the KEY ON. On the Alternator Harness side, measure voltage at C105_B with both the KEY OFF and the KEY ON.

Was this voltage measurement taken on C139_B? C101??? Do you mean C100_C6?

Check this and do Cruisers tip. http://cruiser54.com/?p=110

Good question. Don't know, but that could be a valid reading. Oil gauge has three (3) legs. B+ in (feed) Through gauge, through sending unit, to ground (This wire is where your reading 6vdc) Through gauge to ground

No. Power for gauges is B+ (12vdc).