Ωhm

Welcome to the CC Forum. You got your radiator shroud in place? You jumped your AC Low Pressure Switch, does your AC clutch engage when EFan is ON?

Could have been a "must see". John Wick claims to be driving a 1969 Mustang Boss_429, but in reality its a Mustang Mach_I dressed up poorly to look like the Boss.

Don't forget...............

Somebody give me a cheeseburger.

Your video sure does sound like cross-firing. You mentioned 40psi as fuel rail pressure. Does that drop down to 31psi when engine is at IDLE?

Using a voltmeter or 12vdc testlight (preferred) check for B+ on the following pins (use battery negative terminal for ground): D1_5: B+ (Hot at all times) D2_4: B+ (Hot during KEY ON/CRANKING). D1_6: KEY ON (B+ (Hot for 2-3 seconds)) or CRANKING (B+ (Hot during CRANK)).

Maybe fuel line got crossed over somehow. If engine ran before this, it should run after doing this.

Check your Fuel Pump Relay. Swap it out with one of the others or jumper Pin_1 to Pin_4 with relay removed. Check your fusible links at starter relay.

Possible fuel in the hose between the engine manifold and the Fuel Pressure Regulator (FPR) and/or leaky injector(s).

I'm not going to say this will cure your problem but what about backtracking some wires back to there splices. Check the condition of these splices. Splices have been known to be trouble. Trace each wire back to there splices: D1_2 - Splice_B D1_5 - Splice_A D1_6 - Splice_K Also you have not swapped out the ECU? Correct?

So your getting good reading from your REM. How about starting fluid down the throttle when engine craps out, does it kick and buck? Got spark?

Do you still got the Renix Engine Monitor (REM)?

I have a couple of box head wrenches (sockets) that I put to the wheel grinder and flat'in them out. What I'm trying to say is I took the lip off the box or socket that has no bite on it. Once I did this man do them wrenches grab hold of whatever your taking off.

No. Its a IGN_SW_I1 feed. Hot (B+) only with KEY ON/CRANK.

Yea, your good. Just running the pump with KEY ON. No more listening to the radio using just KEY ON.

With KEY ON only, fuel pump motor will not cycle OFF when key is in the ON position and ECU sees no CRANK signal.

Yes loss of CPS signal would cause a NO START condition. Along with no FP relay action there would also be no spark from the ICM. Since jumping FP relay pin2 straight to ground vehicle START and RUNS just fine means CPS is good. SYNC SIG has no bearing with this problem. Even if you show good continuity between FP relay and ECU, disconnect ECU_C202 and with KEY ON ground pin_A5. Does Fuel Pump motor TURN ON? If yes, suspect ECU, otherwise check wiring.

Seems like your ECU (pin A5) is faulty. Just can't hold the relay coil to ground with KEY ON. I'm not sure how to test. Check for continuity between FP relay (C216_2(85)) and ECU C202_A5.

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.