Hello all, Hopefully someone can help guide me in the right direction in getting my '90 working again. Bear with me on the TMI/ TLDR. Short run - stubles, lugs and stalls under load and I suspect an injector issue but am looking for some second opinions which are encouraged. Any thoughts or ideas are welcome, please!
Symptoms: Under load the O2 reading drops to full lean (and frequently so low that it doesn't register on my O2 gauge) and the engine stubles and feels like it's missing. Under sustained load (more than 10-15 seconds) it's incredibly low on power, stutters, lugs, chugs and otherwise threatens to stall. I held onto it like this long enough to throw a CEL code 17 which apparently is "Oxygen sensor (output not changing)," which is pretty obvious considering the activity of the gauge and provides no actual clue as to the cause. Thoughts: Engines need air, fuel and spark. I cleaned the air filter and don't have a AFM code on the CEL so air doesn't seem to be the problem. It starts immediately and runs fine at idle which doesn't really indicate spark. I suspect it's a fuel delivery problem but with the FP readings it seems that the fuel delivery to the rail is working fine. This leaves me to suspect an injector issue. Indications: 1. Good idle 2. O2 dithers properly at idle once the sensor warms up (about 1 minute after starting). Using a Bosch heated sensor from FM (about 8-10 years old). O2 readings from an Autometer LED style gauge vampire tapped at the ECU. 3. Engine starts cleanly (I do have the occasional issue with the starter solenoid, but unrelated to the issue) 4. Engine burns a shitpot of oil from bad valve seals at start, blue smoke from worn rings over 4K RPM. 5. Fuel Pressure is good, 32 PSI closed throttle, 42 PSI WOT. It's a little low, but has read like this since I installed the gauge 12 years ago. The sender is tapped into the end of the fuel rail so gauge pressure = rail pressure. 6. Air filter is clean, it was my first (easiest) trouble shooting step considering the problem _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
