96 Ciera 3.1. Misfire

[96ciera]

Hey everyone,

Got a question for you guys. What I have is a 96 Ciera with the 3.1. I am getting a trouble code of a misfire in cylinder number 5 and of course it runs terrible because of the misfire. Recently the car died and would not start so I had the control module and coils tested (the no start issue was the crank position sensor). All three coils and the control module passed just fine. The plugs and wires are only about a week old and the cylinder is getting spark. So I think its an injector issue. My question is how are you able to test the injectors on these cars with out have to pull the plenum? I know you are supposed to put your finger on the injector and feel for a buzzing or put a stethoscope on the injector and listen for a clicking. But I can not even see the injectors with the plenum on but I can see the fuel rail. I know there are two great articles available on pulling the plenum and on replacing an injector but I was wondering if there was a way to perform the simple tests without actually replacing the injector. If anyone has gone through this (is this a common problem with these engines since there are two articles dedicated to this) or has any suggestions your help would be greatly appreciated.


Thanks in advance.

[malibu97ss]

If you can identify the wires going to the injector, you could compare the resistance of your #5 to the other injectors to see if the injector has failed electrically. You may also be able to remove the plug for the cylinder, crank the motor for a bit, and try to see/smell if any gas has reached the cylinder. Hope that helps.

[96ciera]

Malibu,

Thanks for responding but the issue I am having is that I can not access or see the injector or the wiring under the plenum. What I am hoping is that someone has a trick or knows a way to be able to get to the injector and/or wiring so I can do the basic tests (and if needed test the voltage)without having to pull the plenum. Thanks for the help because every bit is greatly appreciated in this situation. This issue is driving me crazy!

Thanks

[TrailMug]

A full-featured OBDII scan tool and fuel pressure gauge can be used to perform an injector balance test with everything still installed. I assume you have access to a scan tool, becasue you have the code in the first place -- unless it is one of the newer stripped down codereader-only deals. If that's not useful, you may be able to get a DC resistance reading at the computer if there's no other option. Yank the wiring harness and compare resistances.. Since the 96 uses sequential injection, every injector would have its own pin, and this should make sense (If I'm off my rocker, someone let me know). Of course a resistance/voltage-under-load comparison will only tell you if the injector coil is faulty; for valve health issues like sticking, etc, a balance test or flow tests needs is necessary.