1991 Olds Cutlass Ciera 3.3 v6 would start, run a
jrtvett's "unplug one injector and start" troubleshooting procedure would work if one injector is bad. If more than one injector is bad, then not so sure.
Like you mentioned, one or more injector(s) can go bad and it causes the others to stop working as well. After our experience, I am convinced this observation (fault mode) is correct (see below). Its as if upon warmup the solenoid in the faulty injector shorts, resulting in short circuit of signals to all the other injectors.
We have a 1989 Olds Cutlass Ciera with the 2.8L V6 that recently had the same fault: At least one injector went bad after warmup, then engine refused to restart. All other possibilities were eliminated, including crank shaft sensor, ECM, ignition pack, idle start valve, bad gas, rail pressure, etc.
No Service Engine light illuminated, and there were no fault codes in the ECM computer.
The jrtvett procedure could not easily be utilized in our case because all the injector connectors are underneath the intake manifold and inaccessible.
My cousin is a Ford mechanic told me of an analysis procedure Ford uses to troubleshoot injector problems. They display rail pressure on a LCD or CRT monitor and can see pressure drop with each injector's opening. Unfortunately, if the car is not starting, then this test will not be of much use. The engine has to be idling or at least all of the solenoids in all of the injectors operational to use this test. If engine won't start, then its clear none of the injectors are opening as described above, then no fluctuations in rail pressure would be displayed.
The shop that was working on our car decided to replaced all of the injectors, and the engine now runs like new.
Due to inaccessibility of injectors and fact these injectors were inexpensive ($40-$50 each), it was wise just to replace all six. Grading old injectors is not exact science.
on Apr 21, 2018