Ωhm

Measure voltage at C216_5(86) with the key on (relay removed). Measure voltage at C107_D2-4 with the key on (relay doesn't matter). Should be the same.

When you jumper the FP relay, pin C216_1(30) to C216_4(87) the vehicle started and ran just fine. That can only mean we did something right. Is that where we are right now, vehicle starts and runs with jumper? No voltage drops at fuel pump with jumper? Not sure about C101, that goes to the INJ harness. cruiser54, I understand

No. O2 relay uses pin 87 to bypass the fuel pump ballast resistor during a WOT condition. Your vehicle is not equipped with ballast resistor.

D2 and D3 don't matter. There not on the circuit being tested. D4: 0 confirms splice F (yellow wires). Make repairs, connect battery, cross fingers and start vehicle. Let us know.

200k good scale. Measure from C107_D2-4 to C216_5 (relay pin 86). Looking for zero ohms.

No need to undo anything. Info only. Don't understand "all jumped". Looking for zero (0) ohms. Sound like yellow is splice F.

Might have another case of an open ended wire (not used). Yellow seems like splice F. Pg 16 upper left corner. Lets find out. Disconnect Battery. Continuity check the following (ohmmeter) for zero (0) ohms. Between C107_D2-4 and C216_5 (relay removed) Between C107_D2-4 and C228_1 (relay removed) Between C103_E and splice F. Anyone of these will confirm splice F.

How many yellow wires are there? My guess: 7.

Five (5) red wires tied together.

Your dropping voltage between C103_B and C106_D1-5. Suspect splice E. Page 89. Little circle with an E in it.

Pull the relay out. Take measurements from the pin to any ground. Refer to the following link: http://www.bteventures.com//mj1988electricalmanual.pdf Engine schematic: pg 14 Harness view: pg 89 & 90 Connector view: pg 75 C106_D1-5 is the connector with the yellow cover on it.

I'll assume relay is removed. C216_1 should have B+ voltage. Check voltage at C106_D1-5, should have B+ voltage. Check voltage at C103_B (Engine harness side), should have B+ voltage. Pls advise.

Never

Check out page 75. http://www.eriejeeppeople.com/Jeep_tech/87_90_fuel_injection_renix/Jeep_Renix_Fuel_Injection_manual.pdf

Just out of curiosity, can you get the REM numbers for ST and LT (fuel trim) during idle Closed Loop operation? I'm wondering if there's any shift in these values.

IIRC V8's overheated with the standard grill. That gave birth to the grill with a hump.

That's a V8 304 cu in (5.0 L) Pacer. They didn't make very many of them. Seems like its in good shape. Someone got lucky. Oh yea, nice jeep.

Disconnect ECU Disconnect each injector and verify continuity (0 ohms) between ECU and each injector. Don't have the pin outs you need. Check wiring diagrams for correct firing order.

Suggestions: Check throttle plate angle (gap) spec. Pin each injector back to ECU for correct firing order.

Auto ECU has P/N function. The purpose of this function is to add ≈50 rpms in anticipation of the new load added to the engine when shifted into gear. In reality it backs off IAC (more air) to maintain the same idle rpms. With the Auto ECU you may be able to lower your idle rpms by ≈50 rpms. As mention above, adjust your TPS again and check throttle plate using cruiser54 tip #14. http://cruiser54.com/?p=94

Your REM readings show fuel trim @ 128. This value is either what it is, or its the default value used for open loop. Can you capture the REM fuel trim reading during the short time the vehicle is in closed loop operation? O2 value shows rich. Shot in the dark here, leaky injector.

Looking at the 88 electrical manual your color codes don't line up. Your going to need to pin (0 ohm) each injector wire from the ECU or C101 to determine which injector is which. This assumes 88 wiring is same as 87.

Year?, Model?, Engine? Add this info to your signature.

Need to determine if voltage is present. Need to use the electrical manual for this. http://www.bteventures.com//mj1988electricalmanual.pdf Disconnect and check for voltage on the following pin, headlamps/park ON, engine harness side. C102_4 Pg 69 Connector view Pg 75 Harness view Pg 90

I take it your just looking for front L/R park and side marker lamps to work? All other front lamps work? Make sure bulbs and sockets are clean and good.