4.3 Vortec ECU
Posted by Acrobatic_Box_9654@reddit | projectcar | View on Reddit | 6 comments
4.3 swapped into a 97 TJ with a Howell harness. ECU not responding to changes in IAT, TPS, or MAP sensor circuits. IAT circuit when unplugged is at 5v, when sensor is plugged in the circuit drops to ~3.8v and responds to temp changes. Similar story for TPS. I have tried another ECU w/same service number, swapped chips and had same symptoms.
Any suggestions? Failed ECU seems like the smoking gun, but after seeing it and seeing no change I’m at a loss.
FiatTuner@reddit
check the harness, especially grounds
Acrobatic_Box_9654@reddit (OP)
I appreciate it. Just realized my issue, I’ve been trying to diagnose via the OBD-II port which is connected to the abandoned Jeep harness. I’ll check codes via the ALDL after work and see what I’ve got. 🤦🏼♂️
Acrobatic_Box_9654@reddit (OP)
Got the ALDL jumped and read codes, still had TPS high. Checked ground and continuity, found the female pins on the plug end were bent out of shape. Repaired them with a lock and set the TPS @.41v she’s a sweet runner now.
FiatTuner@reddit
awesome 👍🏻
13engines@reddit
Man, the CPI is the worst version you could've picked. Spider injection you can't get new anymore, only choice is to have it rebuilt.
Acrobatic_Box_9654@reddit (OP)
Work was done prior to me getting the Jeep, price was right and if it gives me trouble I’ll put a 4.8 or 5.3 in. Believe me when I tell you the 4.3 vortec would not have been my first choice.