Need some help with a 36 24X Signal Circuit error (3.4L) I found on my scanner on my '95.

This problem has existed for some time, but has gotten worse, it feels like only 5 cylinders firing. Just replaced plugs (NGK) & wires (AC Delco), wire brushed the coil-pack terminals, used dieelectric grease. I should note, the old Bosch Platinum plugs on the drivers side cylinder plugs had a black carbon almost wet look, and the passenger side cylinder plugs had more of a Worn burnt look. Not sure if that is what Z28Pete referred to in that both tips need to be platinum, else there would be a difference on each side?

Tested each coil-pack terminal's spark & idle both with IAT disconnected and connected. There is no obvious bad coil, spark is good on all, and the idle change with each individual removal was rather consistent.

So what else to check? Haynes says this error is a "Faulty circuit error from coil packs to module" -- I assume the module is the ECM?

Could this be a bad injector? Could a coil pack be bad even if it puts out a great spark? Could the Oxygen sensors be bad? (never changed them) Could low fuel pump pressure cause this? I am a bit baffled, and curious if anyone has ideas before I take it to a shop.

Thanks in advance.

 

*bump* -- nobody has any ideas on this one??

 

Check your crankshaft position sensor. Turn your Haynes to page/section 6-16, and you'll see what I'm talking about.

 

Really? I never even considered that... Not sure what the connection would be, but I'll check it. Thanks.

 

Timing is what it's used for.

 

Of course, the bozo Haynes manual directs you to section 5, NOT 6 where it describes the error code... :-(

The part is only ~$30 -- got one on order -- here's to hoping it works...

 

Replaced the 24x Crankshaft Position Sensor, cleared codes, get the same code (36 24X Signal Circuit error (3.4L)) and same bad engine behavior. :-(

What is the purpose of the 3x Crankshaft Position Sensor in contrast to the 24x? I never saw an error code specific to the 3x one in the error codes listing...

Any other ideas? Could it be the Camshaft Sensor? I'm thinking bad wiring maybe... or ignition module?

 

One of the crank sensors is used for startup and up to 2k something rpms. The other takes over from there.

 

Now that you know that the sensor is good (this is the sensor hidden behind the front damper) check the wiring and connectors between the sensor and PCM. There is a connector near the sensor and the "C" connector (Blue)at the PCM.
Unplug the sensor connector. Pin A (Pink) should have 12 Volts from the ignition switch.
Pin C (Pink/Blk) should have a ground from the PCM Connector C, Pin 18
Pin B has the 24X signal from the sensor and feeds it to the PCM Connector C pin 21. The signal cannot be seen without the proper tools so check the wires with an ohm meter and verify that all connections are good

 

I think this is likely the problem, which nobody here suggested, a bad camshaft, here's a guy w/the same problem, but on a Fiero 3.4L:
http://www.automotivehelper.com/topic535109.htm

:-( Before I goto a shop, anyone know how big a job this is to replace? How about average cost at a shop?