Ωhm

Is that 31psi with engine running or 31psi without engine running? Should read 39psi without engine running. Check vacuum hose on Fuel Pressure Regulator (FPR).

Make sure your KILL SW is OFF or just disconnect the wire at the Fuse Panel (RR WIPE).

Your other relays would have proved out the B+Latch Relay as being bad, ECU as being good. Since they didn't, we looked at wiring, leaving the ECU as suspect.

I'm not saying, I'm hoping. If B+Latch Relay worked properly (relay jumper test) you should be able to get rid of kill switch. @eaglescout526 ECU request help here.

I'm calling that as circuits are NOT open. Next two tests involve the ECU connector. Looking for continuity. Same conditions KEY OFF. KILL SW OFF. D2_2 and C200_7 D2_4 and C200_19 If both test good, all wiring test good. Suspect ECU.

KEY OFF. KILL SW OFF. Remove Relay. Continuity test between D2_2 and B+Latch Relay PIN_2 between D2_4 and B+Latch Relay PIN_5 between D2_4 and B+Latch Relay PIN_4 Looking for 0_Ωs.

KILL SW OFF. Relay installed. Jumper D2_2 with D1_3. Try START & RUN again.

Interesting.

I think having the KILL SW answered my own question and that proved it. Do you have a known good relay? Swap them out, Try START and RUN again. I'm thinking faulty relay, relay (Coil) ON circuit or ECU not controlling B+Latch Relay function.

That's good. Proves we don't need the kill switch. Next question is "will ENGINE START and RUN with KILL SW OFF and B+Latch Relay reinstalled?

Turn KILL SW OFF. Remove B+Latch relay. Jumper wire between PIN_1 and PIN_4. See if engine STARTS and RUNS.

B and C should read 5vdc. It's the MAP sensor supply voltage. I don't know why they say a WOT.

Somehow, I think the toggle SW shuts down the ECU. Anyone else got a understanding for the B+Latch Relay circuit. It's a strange circuit.

Determine which Relay is the B+Latch Relay. Check for HOT AT ALL TIMES on PIN_1 (RED). PIN_4 & PIN_5 should have PINK wires. Pink should help with relay ID.

D1_2, D1_5 & D1_6 testing are all good readings. D2_4 testing shows that we're dealing with the B+Latch Relay. Why? IDK. Let me look for my next question.

Both 2.5L & 4.0L use a B+Latch relay, thanks for pointing that out. When you get a chance, can you do some preliminary voltage checks? Using a voltmeter or 12vdc testlight (preferred) check for Battery_Voltage (B+) on the following pins (use battery_negative terminal for ground): D1_2: B+ (Hot during KEY ON/CRANK). D1_5: B+ (Hot at all times) D1_6: At KEY ON (B+ (Hot for 2-3 seconds)) or CRANKING (B+ (Hot during CRANK)). With KEY ON, measure for voltage at D2-4. Determine if flipping the KILL SW changes the voltage reading on that pin.

The reason I asked about the Fuel Pump is because I'm wondering if that SW kills the ECU. Those PINK wires seem to be B+Latch Relay and I don't know how that affects the ECU (with or without power). I don't think your killing the fuel pump motor circuit.

Does the KILL SW work? Does it KILL the fuel pump only? Is that 'fusible link wire' coming out of the fuse panel to Scotchlok? That Scotchlok show PINK wires and its location show it could be for the B+Latch Relay.

Looks like the connector callout location is wrong. Other connector w/bulb should be instrument lighting, headlight dimmer switch circuit. Don't know why it has a bulb in it. Is that a clutch pedal I see? Could be why C261 goes nowhere.

Coil on Plug (COP) is a programmer’s dream come true.

Problem was because faulty distributors made their way into production vehicles (I6 only). Fault was tip of rotor and distributor drive gear were misaligned when assembled. Spec'd wrong, causing crossfire at higher RPMs. Solution was replace distributor.

As you move the rotor tip more CCW to cover timing for both sides of TDC (0°), you have shifted the gap problem to the MAX advance condition. Moving the rotor tip away from the tower contact at MAX advance. This assumes all things stay the same.

Isn’t timing retarded ATDC and either ‘more advanced’ or ‘less advanced’ BTDC. Just trying to understand the terminology.

Yes I would think/hope the ECU knows enough to never go less than the base timing.