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.
When an engine stalls, there usually are two basic causes: No spark, or no fuel. As simple as this may sound, there is unfortunately a plethora of "troubleshooting" techniques; some are easy but some may require specialty tools and diagnostic equipment. How the engine "stalled" may actually give you some hints on where to begin.
We are not checking for charging system/battery failure at this time due to the fact that the starter cranks strong.
If the engine shut off abruptly, say, like you switched off the engine, I would start by checking for spark. Be careful not to touch the igntion wire ends while cranking the engine as this may result in a nasty shock. Begin by unplugging one of the ignition wires from the spark plug, insert a spark tester in the plug boot and crank the engine to see if there is spark. Don't have a spark tester? Try inserting a screwdriver into the plug boot, position the screwdriver shaft about 1/8th of an inch from a grounded surface and crank the engine. A strong arc indicates that the ignition system may not be the problem at this time. No spark could mean a bad ignition coil, Cam Position Sensor, Crank Position Sensor, Mass Airflow Sensor or even a bad Ignition Module. Note: Ignition coils can be tested by using an ohmmeter (you will need the primary & secondary resistance values). Ignition modules can be tested using a module tester (Parts stores like AutoZone actually tests these for free).
Got spark? Let's move on to the fuel system: Did the engine "cough" and slowly lose power as it began to stall? It's probably not getting gas. Try spraying Starting Fluid (ether) into the intake tube. Please exercise extreme care as you are dealing with highly flammable gases; backfiring is not uncommon in these tests, so wear protective equipment (goggles) and have a wet towel handy just in case you start a small fire. Note: Some vehicles may not run/start if the intake tube is left off, if so, try reconnecting it to the airbox after spraying. If the engine "fires up" after spraying ether into the intake tube, then dies shortly after you stop spraying, your problem is in the fuel system.
Did I mention specialty tools required for further diagnostics? Try to get hold of a "Noid Light" tester if you wish to check for fuel injector malfunction. The term "Noid" is short for "solenoid" --- as in fuel injector solenoid. While cranking the starter or with the engine running, a good fuel injector will cause the tester to pulsate brightly, while a bad injector would have intermittent pulses or none at all. Replace injector(s) that test bad.
For fuel pressure checks, a Fuel Pressure Tester needs to be connected to the schraeder valve on the fuel rail. These tests will let you know if your fuel pump if functioning. No pressure while cranking the starter? Does the pump "prime" itself (usually a 2-second buzz) as you turn the ignition to "on"? Be sure to check the fuel pump relay first before you drop the tank and replace the fuel pump.
By doing your diagnosis in steps, you narrow down the possibilities and will eventually "zero in" on the culprit.
I hope this helps'
LouieBenz
That is exactly what my 1989 Olds Cutlass Cierra 3.3L V-6 is doing. I have replace fuel filter,fuel pump etc, same as above. I am changing the fuel injectors this week. I willl post my results.
After reading this article I went outside and unplug the injectors one by one when I unpluged the last injector my 1989 Olds Cutlass Cierra 3.3L V-6 started right up. GOD bless I been driving a rental and spent about six hundred try this trying that on my car the fuel pump,fuel filter etc,. I will install the injector this week 10/09/2011. Blessing to the people that help me resolve my issue.
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That is a very good answer!
THANKS. It took care of my 1988 2.8 V-6 5SPEED CHEVY BERETTA. I didn't have much more hair left to pull out.The next thing was going to be a trip to the auto recycling center.I had run out of all knoun options.THANKS AGAIN.
My 93 olds cc started great cold wouldn't restart when warm, it was ignition control module.
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