Lots of things are going on with this one.
Runs rough, does not go over 40mph, has tons of DTCs plus the left front window does not work. After reading the tech info and operation for the TCM it appears that the car is in limp mode which is preventing it from going over 40 MPH.
Immediately you can hear a dead miss. This thing is running on 3 maybe even 2 cylinders. The ECM had called out codes for a misfire and open fuel injection circuit on #2.
First thing was to do a compression check, I used the Pico for this test but didn’t have my high amp clamp, so I set up the scope channel “A red” across the battery positive and negative terminals set it for voltage and inverted signal to capture compression pulses. I also use the ignition wire clamp on the number one cylinder plug wire to capture the ignition signal for reference.
The result was a bit noisy as you can see in the capture, however the compression pulses were okay. Next up, starting with the number 2 cylinder I’ll check the fuel injector circuit, injector, plug and coil.
If I could post a video you would see the whole engine jumping up and down with the misfire.
What do we know. We know the compression was good and we needed to further diagnose what was causing the misfire. This required removal of the upper intake plenum, throttle body, airbox and disconnecting of various sensors.
With that stuff out of the way I started with the injectors, each one was checked against the number 2 injector to see if it was in spec and had no opens or shorts which it did not. With the injector verified it was time to move on to the injector wiring and circuit testing.
Since this was a 2-wire configuration and the power side feed from the PCM was good it was easy to identify an open wire on the control side of the circuit for the #2 injector.
Following the wiring diagram I did visual inspection of the harness looking for damage or that beautiful NJ corrosion “green crusties”. Wash underneath your cars people!
Boom in front of the engine below the upper radiator hose and lower intake assembly I found the culprit. The broken tan injector control wiring sticking out like a sore thumb. After separating the connector to pull it up so I could have access to repair the damage I noticed the temperature wire (tan w/ black stripe) was chowtered up also.
A little wire repair, cleaning, some solder, heat shrink, and it’s a smooth runner. Took it for a spin and ran it up to 65 mph no problem. The limp mode was cleared once the injector circuit was repaired. No more Check engine light but there is still some work to do including some new stuff I found while driving
Fix the broken wire on driver’s side window motor, inspect the hvac fan (it’s making a squealing noise) behind the glove box found a bad motor and replaced it, inspect and repair a frozen hvac controls unit and cable, Found a broken ground wire at the front right side of the engine compartment and repaired it which corrected the issues with the lights and installed a new hatch switch with lift struts and wiper blades
