OK, did a lot of testing today. Also cleaned and properly grounded injector resistor pack just to make sure.
So engine still runs rough and revs rough when cold, but runs (no change). Once warmed up to about 180F, it runs so poorly it wants to stall and is hard to rev (no change).
Disconnected full load throttle switch and full load vacuum switch, no difference.
Warmed up, I supplied fake 24 inHg to Bank B FPR (which is new), and it ran much better, but still rough, equivalent to when it was cold. (Sorry, don’t have my fuel pressure gauge). But w/ 24 inHg to FPR, it STILL runs extremely rich. Car holds 10 inHg.
Removed fake vacuum to FPR, applied fake 20 inHg to ECU, no difference whatsover.
I have no equipment to test injector pulse width
I did compression test in October, all good (180-195)
So i think I’m now down to :
(1) Bad engine (maybe compression has gone bad since testing?)
- I will need to do another compression check
(2) Injectors are not being told to lean down the mixture either due to
SO, I did a resistance check with GROUND on ECU harness and got this (battery disconnected from car):
- 0.0 ohms: Pins 1 (ECU Ground),16 (Injectors Ground),17 (Injectors Ground), 23 (O2 Sensor Shield), 26 (Start signal), 34 (Injectors Ground), 35 (Injectors Ground)
- 7700 ohms: Pins 8 (Bank B Injectors ON),9 (Bank B Injectors ON),11 (Bank B Injectors HOLD),12 (Bank A Injectors HOLD),13 (Bank A Injectors HOLD),14 (Bank A Injectors ON), 22 (Main Feed), 27 (Bank B Injectors ON), 28 (Bank B Injectors ON), 29 (Bank B Injectors HOLD), 30 (Bank A Injectors HOLD), 31 (Bank A Injectors ON), 32 (Bank A Injectors ON)
- 7800 ohms: Pin 15 (Fuel pump relay)
- 6800 ohms: Pin 18 (Engine speed signal)
- Infinite ohms: Pins 3,4,5,6,7,10,19,20,21,24,25
VIN 141xxx. Looking at electrical chart, the ground signals are properly grounded. Not sure what the rest means, Any electrical gurus out there who can make sense of the ohm readings?
** history of tests: CTS, TPS and ATS all put out correct signals. Wiring from those to ECU Harness all good. Fuel injectors harness good.
Spark good. Ignition timing good. **
So bad ECU, bad engine, or bad ECU wiring to injectors. I hope I’m getting close.
My gut says, the fuel injectors are pulsing like it’s full throttle. I just don’t know why. It ALWAYS runs rich, and misses/rough at idle, but the more RPMs I give her, the smoother it runs and the misses almost go away. I just can’t rev past 3000 sitting in the garage. Maybe at 6000 it would run smooth as a top.