Ωhm

Unless I missed something, Year, Make, Model, Engine, Year, etc, etc, etc.

By using one 10 amp fuse, all wiring size must be gauged to carry 10 amps or better, except from relay pin 86 to ground. And yes, your switch could see 10 amps with a short to ground between the switch and relay pin 85.

Why is that switch in drawing 1 connected to ground. That scares me. But like Jeep Driver said, use that switch to control the grounding side of your relay and just run power to both 85 and 30.

I'm sorry but what do you mean by " 02 signal circuit" ? I understand the heater needs a ground but I thought the "ground" for the O2 signal was the oscillating voltage the ECM needs to calculate air fuel ratio :hmm: . Thank you for the diagram Hornbrod O2 signal circuit consist of (ECU pin D9) 5 volts on top of a fixed resistor, connected to the O2 sensor (O2 pin C), through a variable resistor and then to ground (O2 pin B. Between these two resistors the signal line is tapped, and the ECU read this voltage. This type of circuit is known as a voltage divider. Example would be when the variable resistor is of equal value to the fixed resistor, causing the output signal to show 2.5 volts. As the variable resistor value increases, (high oxygen content) voltage increases on the signal line. As the variable resistor value decreases, (low oxygen content) voltage decreases on the signal line. This happens many time per second and a DVM will not show this. But when the O2 sensor is disconnected a steady 5 volts (4.98 volts) will show on the harness side of the connector (O2 pin C). All of your reading and values seem good, within the limits. So why is your vehicle running lean? There was a reason you replace the ECU and O2 sensor. MAP, clogged injectors, fuel pressure, something causing this lean condition.

Pin B is a shared ground circuit for both the heater circuit and the O2 signal circuit.

I take that to mean O2 sensor connector to engine block ground = 0 ohms. So the vehicle is running trouble free and the monitor is in error. or Everything you did and see is true and your engine is running lean. Your not burning Corn-85 are you?

Thanks for the photos. Looks like a new thermostat gasket, that a start a least.

Not to be rude or anything like that, but can we peek under her hood? I'm just that kind of a guy.

Welcome

Should just tell the ECU to shut off the fuel pump relay during crank. Starter relay will supply battery voltage to the fuel pump. By-passing the ballast resistor. Disregard this foolish statement I made. ECU does not shut off the fuel pump relay.

No. Your trying to start the vehicle and you don't need any more fuel.

Keep that classic as is. Stay on the cement. Don't do anything except maintenance items.

Check gauges fuse (7.5 amps) first. I'm assuming your IP cluster is completely void of any voltage sources and all other things are connected properly. If this is the case, then using a fused jumper (7.5 amp), note maximum 7.5 amps, jumper to the following: C203_6_13 (WHT/BLK) This will give you more than just your fuel gauge. Should power up all your idiot lights, if and when they're needed. A simple test would be to watch the brake lamp indicator while cranking. Should light up during crank.

C203_1_4_9_16 (ORN/BLK) Any where on the ORN/BLK wire.

About the only thing I could add, if its not the TS switch, is trailer tow wiring on your vehicle? This would be common to all the circuits mentioned.

You also fixed the fuel pump ballast resistor by-pass circuit. A condition that happens during heavy loads. Full battery voltage to the fuel pump.

Your're going to need to look at the wiring diagrams. One diagram is worth a thousand typed words. Take 2 aspirins if necessary. B+ feed (PARK FUSE 10 amps) through Headlamp Switch to (INST LPS FUSE 5 amps) to: C203_1_4_9_16 (ORN/BLK) Pg 61 C203_5_10 GND side (BLK) Pg 61 IP Cluster view Pg 95,96 Connector view (C203) Pg 78

For what ever reason, I can't see the photo. Just shows up as a file name.jpg.

Welcome http://www.bteventures.com//mj1988electricalmanual.pdf

Suggestion only: Fuel pump volume test, possible pinched or dented fuel line.

Key on, clicking relay is a symptom.

Yes. C157_D goes directly to the B/U lamps. When connecting your switch, use a fused inline (7.5 amp) to connect to B+ (SW IGN is best). Other side of switch to C157_D.

Automatic or manual? Fix your switch. otherwise: C157_D IP side BRN w/trace CAB side BRN/WHT pg 71

Won't this affect INJ timing also? I understand the 'closer' side of this, but moving the pickup, changes TDC. No. Injector timing is controlled by the sync generator in the distributor. Sync signal determines INJ sequence. INJ timing uses teeth count on the flywheel. Not here to start a pissing contest, just a understanding. Maybe a new topic, don't want to hijack thread.

Won't this affect INJ timing also? I understand the 'closer' side of this, but moving the pickup, changes TDC.