Ωhm

how does the system work exactly to bypass the fuel pump resistor on 88-90s? Now your question has the word "exactly" in it. So keep in mind both FP relay and 02 Heater relay that the ECU controls the coil side of each relay. Meaning power (B+) to the fuel pump motor, with or without the ballast resistor, is switched from the fusible links. The same thing is applied to the Starter Relay except that's controlled by the IGN SW with the key in the CRANK position. Back to the drawing board or now are we good? Great question.

For manual bending use Tube Bending Springs. Supposedly no kinks.

No. Wire to the resistor, then the fuel pump motor is from the Fuel Pump relay. Wire to the pump is either from the 02 Heater Relay (WOT) or Starter Relay (CRANK). Should work just fine. The ECU only controls the Fuel Pump Relay coil side and/or the 02 Heater Relay coil side when needed.

Don't know about RENIX, but what about the transmission (TCU) stuff? Transfer case (TC) stuff?

Three conditions feed (B+) to the fuel pump motor. One (1) using the ballast resistor and two (2) bypassing the ballast resistor. Conditions are as follows: 1. During CRANK. B+ is supplied by the Starter Relay. Ballast resistor is bypassed. 2. During WOT. ECU knows when vehicle is in WOT and activates the 02 Heater Relay. Ballast resistor is bypassed. 3. At all other times, Fuel Pump Relay supplies B+ using the Ballast resistor in series with the fuel pump motor circuit.

Welcome to the CC forum.

Groovy.

Don't. You got a 2.5L. We need to wait and see how these do. Watched your REM recording (youtube) made about a month ago. IDLE seems HIGH (≈1050rpms). Shows no CLOSED THROTTLE @ IDLE. Intake air temp (f°IA) also seems high @ around ≈245F°. ST shows ECU is adding fuel, but could be normal for HIGH IDLE.

My pleasure.

Found on YouTube.

_mj1988electricalmanual_1.pdf

Check your Fusible Links on the Starter Relay.

Love "The Queen of Soul"

When AC compressor clutch is engaged, make sure you have battery voltage (B+) on D2_6. If you can also check this using a testlight, looking for brightly lit. Same as if you put the testlight across the battery terminals.

Happy to help.