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Hi all. I’m working on a new to me 1989 Comanche, 2.5L TBI, AX5, 2WD. It starts right up every time, runs fairly smooth after replacing all vacuum lines, but is running very rich. Strong fuel fumes will burn your eyes with it running. Black sooty spark plugs. My situation seems to be the same as this previous post here. Oxygen sensor heater has battery voltage on yellow wire, 6 ohms between heater supply and ground, 0 ohms to battery to connector ground, and 0V on signal wire with sensor unplugged. My understanding is there should be 5V. The gray sensor wire has 0 ohms to ECU connector pin 35. When running, the oxygen sensor signal starts about 0.70v and increases to 0.94v and stays there (digital multimeter). Things I’ve checked per the 1989 FSM (have the full set) - grounds per cruiser’s tips - EVERY engine bay connector cleaned - Thermostat is new Motorad 195: previous had failed and wasn’t allowing engine to reach operating temp - MAP sensor function appropriate - CTS function appropriate - MAT: ~1600 ohms at operating temp when running and sensor unplugged. Pulled and used a heat gun directly on sensor element and it immediately responded by dropping below 100 ohm. So I believe the sensor works but it’s getting cooled by the excess fuel. - TPS: this one also might be a problem, adjusted WOT voltage to 3.65v but at idle it’s 1.2v which seems high. Am I correct in my thoughts on the ECU oxygen sensor circuit being faulty? I don’t have a spare to swap in, I’ll have to purchase one.

Long time listener, first time caller! Ive got a lot to explain, so ill get right to the point: 87 Comanche HO Swap Ran after swap fine for a month Problem: A short in the dash powerside wiring (the small orange/black wire) caused a no start problem The dash light wiring has been repaired Symptoms: No spark from coil No injector pulse Fuel pump primes but not running during cranking Intermittent Voltage gauge operation Tachometer not working Diagnostics: CPS is newish and tests at 235 ohms and puts out .5v ac current during cranking 5v at tps and map TPS tests puts out 0.8v MAP tests good O2 tests at roughly 400 ohms Both temp sensors test good Replaced coil, ICM, coil lead 12v and good ground at ICM 3 prong plug Ground at ICM 2 prong plug (not sure if this is supposed to be, the wire is yellow) 12v to coil from ICM Opened up ECU, looks good and all testable components tested good The four relays behind the battery all test good, same with the relay on the drivers side engine bay Cleaned C101 connector (was filled with goopy sticky black stuff) Cleaned plug going to fuse box 9 filled with same stuff) Checked the CPS resistance at ECU pins D1 and C1, came back same as at CPS Checked all fuses and fusable links Cleaned ground strap and connections at the starter relay I thought I had no power at ECU but I think I am testing the wrong connectors (D10 and C11) my wiring diagram seems to be wrong, what pins should i check for power at? I am honestly stumped. Any help would be greatly appreciated, Ive read through nearly every forum I can find

Hello All! :thumbsup: So I heard somewhere that I could swap out my stock injectors (I have a 1992 4.0L in-line 6, :)) for some '4-way spray' ugraded injectors that could possibly bump up my fuel efficiency and give me a little boost in power/torque. Is this true...? I have an otherwise stock 'manche. If so, what is the model, make and possibly part number of these injectors? I 've looked a couple places, but they just mention 'Neon' or '703'...I'm not sure exactly what that means... Where could I purchse these new, once I know what I need? Many Thanks! :brows: :bowdown: