Hi Kevin, Hi Nick,
Yes I do have the helm manuals for the car. I have little to no experience with electronic engine controls & fuel injected cars from a "hands on" aspect.
The car is sputtering and it seems to have a miss. I thought water in gas, so I added techron(big bottle) & replaced the fuel filter. No joy. I next pulled all plugs; even # plugs had clean, white center porcelians, which seemed odd as the electrodes were charcoal; odd # plugs electrodes & center porcelian were charcoal. No visable damage, no fouling, broken parts. I had my FR2LS plugs saved so I put them in & no change. Resting state battery voltage is 12.5, I knew I wasn't gett'in lucky!
I had no SES light but I used Gordon's jumper kit to look for codes in the ECM and the CCM. 12 in ECM and --- in CCM so I went to 6E section, and checked fuel pressure, 50psi on KOEO tests, engine cold & 48psi with engine running @ hot idle. I used my inductive timming light to check the wires & get a feel if there was energy in all wires, and I had good light pluses on all wires. I put a Vacuum gauge on it also & 15"hg @ idle speed, hot motor. I did all those checks while I was warming up the motor to get fuel psi w/ motor running. Book said KOEO PSI tests w/cold motor & hot motor for running PSI test. I found no fuel in pressure regulator hose & since the PSI w/ motor running was good I figured the regulator was good. I put 12" hg on it w/ motor off and it held vacuum. The MAP hose was on & since it was only $30 I swapped it, no change. I smells lean to me so I figured no vacuum signal to ECM for A/F adjustment. Just a guess. I should know better.
The rest of the stuff in book talks about a Tech1A so I figured I need to have it scanned. I was afraid of what chart A-7 said about looking for spark & the cats so that is why I used my inductive light. It always worked on my 72 LT-1 & it had GM C/D ignition and I also checked the FR2LS plugs for wetness after swapping them & the fuel filter because I could tell right away the "miss" or "sputter" was still there. Also the exhaust smells lean. I figure big vacuum leak or all the injectors quit at once? I hate to say this but I feel like blocking the T/B extension but usually a vacuum leak leads to high idle & mine is normal, 600 or there abouts. Oh and this throws me, it started to sputter or miss very subtly and by the time I went about 5 miles it was a full miss. I also turned on the power key and it was the same miss. That's why I thought bad gas because I just tanked it. I siphoned out about 5 gals worth & let it sit to check for water, no soap. With no codes I'm quite lost as I can't take the odds of all 16 injectors going at the same time, and I figure if the O2 sensors were N/G it would be in "closed loop" only? I guess if no sensors actually break I wouldn't see a SES light & codes. I just don't understand enough to be very effective at trouble shooting, guess I should have went to Gordon's school before buying a Z.
Thanks for the sincere inquires & the knowledge you all share with us rookie Z drivers.
Tom