Ωhm

Check out Pg78. (Note the Note) Jeep_Renix_Fuel_Injection_manual.pdf What are the wire color codes for this mystery plug? Looking for TAN & BRN W/TR.

Secondary Ignition (High Tension) consists of coil wire, spark plug wires, distributor cap and rotor. All items are maintenance items. If good, check Cruiser54 tip #13 Renix Distributor indexing, as mentioned above. https://comancheclub.com/topic/73472-13-–-renix-distributor-indexing/#comment-788499

Poor spark can cause plugs to run RICH.

Leaky internal diaphragm will show up here. Vent used for FP regulator to sense ambient air pressure. @54bobby

Seems you stuck with it. Great find for the problem.

Hard Times: Charles Bronson as Chaney.

If your testlight was on pin C156_K, this would be normal and a testlight would blink. Try same hookup but instead use C156_L with KEY ON. Should make testlight blink.

HEATER SYSTEM_VACUUM SCHEMATIC.pdf

Create Signature. Add Yr & Eng info.

I think OPEN circuit causes FULL on gauge reading.

Aren't there two fuses for the TCU? One in the fuse panel (7.5A) and one inline (15A).

....... Comanche Nation. Comanche Nation Collectables

March 7th, 2026 - RIP

That slot was used for the bumper jack. Should have 4 of them. Yes, I'm old.

No. Good question. Either way should work. Myself I'd disconnect the CTS, connect DVOM on CTS pigtail (not the harness) and watch the Ω's. Keep in mind the ECU will default to using the MATS for CTS values and adjust the temperature accordingly (simulated Engine Warm-Up).

CTS is a problem sensor to work with. Maybe not so, 38 yrs ago. It's a plug for coolant and it's threaded into the block. One mistake and your block's in trouble. If it does come out, make sure to rid the passage of all casting debris. Disconnect CTS connector (C222) and using a DVOM (don't use auto range) measure Ω's across the CTS (C222_A is GND side). Watch meter during cold start, warm up and then idle. Look for opens, shorts or maybe no movement at all.

During WARM-UP MODE OPEN LOOP, a faulty Coolant Temp Sensor (CTS) causes the ECU to look at the Manifold Air Temp Sensor (MATS). ECU will add ½°C for every 85 RPM's seen by the ECU. Takes time to figure this out. If you're holding onto a REM, you should know right away.

Same words used with safety belts, helmets and guns. I think they're trying to make me feel bad.

When is the electronic valvetrain going to show up. No cam. No gearing. Valves operated by solenoids, controlled by the ECU.

What about a nice 'vintage spinner' for that center cap?

Distributor cap, rotor, plug wires and spark plugs (entire secondary ignition) are all maintenance items. How do they look?