Ωhm

Using a voltmeter or 12vdc testlight (preferred) check for Battery_Voltage on the following pins (use battery_negative terminal for ground): D1_5: Battery_Voltage (Hot at all times) D1_6: At KEY ON, (Hot for 2-3 seconds). During CRANK, (Hot at all times). D2_4: At KEY ON, (Hot at all times). During CRANK, (Hot at all times).

Sounds like crossfire in the distributor cap. Cruiser Tip 13 - Renix Distributor indexing Fuel Trims values are well within the ECU's range of authority. Yes, ECU did add fuel but still in Closed Loop (CL).

Look on page 20 for information on the resistor pack and how its wired. _mj1988electricalmanual_1.pdf

No, if my understanding of this circuit is correct. CPS creates AC sine wave. This AC sine wave lives within a 4.1vdc world on the ECU. Using Analog to Digital converter, AC sine wave (analog in) is converted to pulsating DC square wave (digital out). Now the ECU can count these square waves and determine exactly where crankshaft (piston) is. Based on a certain number of counts (4cyl/6cyl), ECU will then send a square wave to the ICM and fire the coil. In return the ICM sends a square wave to the IC Tach (gauge). Tach then counts the square waves over a certain amount of time and displays the engine RPM’s, always repeating this process.

IDK. One of Cruiser54 photos.

FI Snickers or Butterfingers?

88 should do it. _mj1988electricalmanual_1.pdf

While that front bumper is off, check front grille. It's upside down. Welcome to CC.

Whatever the REM shows is the value used by the ECU for coolant temp. Suggestions: Pressure test fuel rail for leaky injector(s). Vacuum hose between Fuel Pressure Regulator (FPR) and intake manifold, look for fuel in hose.

Few questions for the REM. When at High Idle, is ECU in OPEN or CLOSED Loop? When at High Idle what are STFT and LTFT values? Are they holding steady?

If you have a testlamp check GND using that, if not buy one. First reading should be how bright across the battery terminals (reference brightness). Next connect testlamp clamp to + side of battery. Disconnect Fan connector and on the GND side of the connector at the vehicle harness, stick GND terminal. Should illuminate same as battery voltage test. Now testlamps don't draw the current like fan motors do, but they do draw current, better than DVOM's. Any 12vdc lamp, brighter the better, can do also.

Maybe something with manifold vacuum. "T" in a vacuum gauge near the Vacuum Release Valve on the Brake Switch. Check how vacuum is holding.

Did she have kind words for you?

Both of the above PSI numbers could be correct. Confucius saying Man with one tire pressure gauge will know his tire pressure but man with two tire pressure gauges will never know his tire pressure.

Yes. The bored-out TB is the cause for your LEAN condition as seen by the ECU (O2S).

For myself I’m a purist, but I also believe your jeep your call.

Someone on here posted this once. If I knew/remembered who, I'd tag the picture.

Using a voltmeter or 12vdc testlight (preferred) check for Battery_Voltage on the following pins (use battery_negative terminal for ground): D1_5: Battery_Voltage (Hot at all times) D1_6: At KEY ON, (Hot for 2-3 seconds). During CRANK, (Hot at all times). D2_4: At KEY ON, (Hot at all times). During CRANK, (Hot at all times).

Thanks for help keeping me straight. I meant C156, not C158. Ignore C158 in my statements.

C158 refers to the connector number. Photo shows that connector with pin callouts and location.

Disconnect C158. Determine if SMOKE goes away. If yes, problem could be C267 or C268. C267_A is a known issue.

88ElectricalManual still calls it a Engine Speed Sensor, but changed the ECU verbiage to ENGINE SPEED INPUT. C201_D1 at ECU is NOT sensor ground as shown in the 87ElectricalManual.

With both CPS and ECU disconnected, each wire has continuity, each wire is NOT STG, but could each wire be shorted together?