After injectors were replaced, the mechanic sprayed in that area and found no leaks.
i did the same and found no change in rpm.
Another mechanic did a smoke test and found
small leak from the pcv grommet and it was replaced with new one.
Only code 12 stored.
Timing is 8-10BTDC.
Converter was checked at 2 muffler shops, not clogged.
Would not a defective o2 sensor show a code?
One mechanic had checked compression but i think it was done on one cylinder.
I will check all 6.
Doesn't this engine require 4 o2 sensors.
how should i test the o2 sensors?
I'll check the o2's tomorrow.
Thanks for your help.
Sorry I have not replied to you sooner, did not mean to leave you hanging but I had family health issues that take priority.
Last time we talked you suggested checking the o2 sensor.
1) Original o2 sensor heater element showed no resistance; and real-time o2 output
measured at ECM was .020-.080v instead of .200-.900v, crossover was approx
1x /sec @750, 2x /sec @2000 rpm. Amplitude low but frequency good.
2) Checked circuit integrity of o2 heater and signal: good
3) Replaced o2 sensor with oem Denso.
4) New o2 sensor heater element measured 3.5-15ohms; and real-time o2 output
measured at ECM was initially .340V for 30 seconds then dropped to .020-.030V at
750rpm; .060V @2000rpm @45mph cruising at level, and .200-.720V @ 2000rpm cruising uphill.
5) Performed back pressure test utilizing the o2 sensor hole. There is only one o2 sensor
and it is located pre-catalytic converter.
Result was: 0.5psi @750rpm, 1.0psi @2500rpm, and 1.5psi with sudden throttle.
6) Final result: car performs with same symptoms of hesitation at partial throttle at any speed but not as bad. Car hesitates and stumbles then seems to clear up then strong acceleration.
1) Why is the o2 reading so low at idle, ex: .060v instead of .2-.8v.
2) I tested backpressure .5@ idle and 1.5@ sudden throttle. Isnt under 2.0
I will take my car to where i bought the last convertor and have them check it tomorrow
morning and ill let you know what they found.
I took the car in yesterday morning to check the condition of the converter and muffler.
1) They put it on the lift and found the converter and muffler to be good.
Isuzu spec states if 1 3/4-2.0psi @2000rpm backpressure that converter is plugged.
I'm getting .8-1.0 psi @2000rpm.
2) They noticed the connector to the MAP sensor had a broken locking tab and used
a tie wrap to secure the wires to the sensor mount. I took it for a test drive and 95%
of the hesitation problem was gone. Pulling away from a stop at low rpms it ran
strong. They suggested I check the integrity of the connector and wires.
3) Drove to a gas station to fill-up and on the way there were no problems. After restart
it went back to hesitation problems.
I subscribe to Mitchell1 and Alldata and I am presently downloading wiring diagrams
so that I can check the wiring harness this weekend.
I have not rated you yet because i thought as soon as i did it closes this thread and it
helps me by reviewing your answers.