Ωhm

You got one (1) wire between IGN SW & Starter Relay. Check for OPEN circuit.

When engine fails to START/CRANK, do you lose power to everything? When this happens do you lose power to everything with the KEY ON?

At Fuel Pump Motor, disconnect C139. On the Fuel Gauge side of the harness, ground C139_B. KEY ON. Does Fuel Gauge read Empty? On the Fuel Sender side of harness take continuity test between C139_B and ground. Does ohmmeter read between 0-88 ohms?

Fuel Pump has three (3) sources for voltage. 1. Starter Relay during ENGINE CRANK (Battery voltage). 2. Fuel Pump Relay during KEY ON (2-3 seconds)/ENGINE RUNNING (Battery voltage - Ballast Resistor voltage drop). 3. Wide Open Throttle (WOT) (Battery voltage). O2 Heater Relay serves two (2) purposes. 1. When relay is de-energized (OFF), O2 Heater circuit is ON. KEY ON voltage is supplied for 2-3 seconds since its being fed (B+) by the Fuel Pump Relay (engine fuel prime/heater ON). ENGINE RUNNING voltage is fed by the Fuel Pump Relay all the time (fuel pump running w/ballast voltage drop & heater ON). 2. During WOT, O2 Heater Relay is energized (ON) and voltage is supplied directly to the fuel pump, by passing the Ballast Resistor.

Hope those are beers & cheers and not beers & tears. Playing the Blues tune makes me think it could be the latter.

Don't know Parts. My train of thoughts was larger tank might need shorter fuel filler neck or vice a versa.

Funny how no 16 gallon tanks have showed up yet, but I've only look at 25 VINs.

Using your Sales Code Decoder per VIN (nice job by the way), three (3) different size Fuel Tanks (gallons) show up. 18.5, 20 & 23. Do all three tanks use the same filler neck? I'm wondering if there could be a mismatch between Tank size and Filler Neck.

If Intermittent Wiper/Washer Module is bypassed. Yes, bad switch or wires to/from switch.

Your vehicle is being difficult. You mention that your O2S came to life after some light accelerations. During this condition exhaust manifold acts like a blow torch and possibly heated up the O2S. I know you have check out the O2S Heater circuit for continuity and the REM shows O2S Heater voltage. But you'll need to tax (current flow) this circuit. O2S Heater element is 6ohms, so ≈12vdc÷6ohms=≈2amps. Remove O2S Heater Relay. Connect Amp Meter between Battery Positive and C228_3(87a) on the O2S Heater Relay Block. Does circuit flow ≈2amps of current?

Disconnect C171. Connect Testlight to good ground. Probe C171_D. KEY ON. Does Testlight shine brightly? If yes, jumper C171_D to C171_B. KEY ON. Does Washer Pump run?

KEY ON, Push Washer Switch.

Connect Test Light between C169_B and Battery Negative (-). Does Test Light glow? Next step: Connect clip side of Test Light to Battery Positive (B+). Probe C169_A. Does Test Light glow?

How did you hook up the Test Light? Between C169B(+) & C169A(-) or between C169B(+) & good ground.

Keep the bed, add duallies. Should make you the talk of the town.

Do listed components work with the KEY in the ACC position?

The ECU is a pricey item for replacement, especially when it doesn't solve the problem. Did you ever run a Compression Test on each cylinder?

A long, long time ago, I was surrounded by hundreds, if not, thousands of MJs. Even more XJs. Now I live in the "Land of the Ford Ranger". Haven't seen one in over 30+ years, but I keep looking and looking and looking......

Or the wire between the IGN SW and the Starter Relay coil. Disconnect both C267 and C268 at the IGN SW. Using a fused jumper, jump C267_S to C268_B3. CAUTION STARTER SHOULD ENGAGE. Does Starter Motor engage?

Your smoke machine uses positive pressure (above BARO). Most vacuum hoses are under negative pressure (below BARO) and don't require hose clamps. Five (5) minutes with 20"hg (positive pressure) without no large or small (not super small) leaks, tell me, system is good.

Normal during ENGINE CRANKING.

I'm trying to say, there's a different kind of hose (rateing) for being submerged in fuel. Hope your Yeah meant that.

Hope you replace it with in tank fuel hose. Something about hose submerged in fuel.

Added question.

Question on Brake Warning Lamp. Does lamp light during engine CRANK? Is lamp lit with KEY ON only?