Misfire/rough idle

[dreager]

Did search but nothing close.

Just bought this '92 PAU 300Kkm. Showing service engine light. Pulled codes 31,41,42,55,56,57. Used coil packs were installed prior to my buying it.

Would the cam sensor cause egr/spark issues ? (My sons regal has shown code 41 for 2 years with no other issues.) Is it the ign. module below coil pack maybe. ?

Thanks in adavance

[Blue Bowtie]

Check the condition of the mounting plate for the ICM. The module gets its ground through that plate, and they tend to corrode after a couple of decades. Don't forget to apply thermal heat sink compound after you clean the plate.

[dreager]

According to my "Buick supplement" manual, code 54/55 are EGR flow test failures. 56 usually follows.
Apart from the suggested possible cracked wires and loose terminals is it normal for the egr valve to die, or would wires be the culprit ?

[HotZ28]

You can disconnect the negative battery cable and clear the codes on this model ECM. Take it for a drive and recheck for new codes. If the EGR code reappears, you must have a malfunctioning EGR. On an engine with this many miles, usually they are gummed up with carbon and a good disassembly and cleaning will restore it to normal operation.

Would the cam sensor cause egr/spark issues ?

The cam sensor controls injector firing timing and has nothing to do with the EGR/spark issues. Code 41/42 can be the cam magnet, CKPS, sloppy timing chain, or the cam sensor.

[dreager]

[quote=HotZ28] On an engine with this many miles, usually they are gummed up with carbon and a good disassembly and cleaning will restore it to normal operation.

Thanks for the reply.

This one is digital. Are you saying take it off (unbolt) completely to clean below? I take it I'll need a new gasket then. Is gasket paper a reasonable fix as being in small town canada it could take a while to get one, or permatex gasket maker ?

[dreager]

Originally Posted by HotZ28

You can disconnect the negative battery cable and clear the codes on this model ECM. Take it for a drive and recheck for new codes. If the EGR code reappears, you must have a malfunctioning EGR. On an engine with this many miles, usually they are gummed up with carbon and a good disassembly and cleaning will restore it to normal operation.



The cam sensor controls injector firing timing and has nothing to do with the EGR/spark issues. Code 41/42 can be the cam magnet, CKPS, sloppy timing chain, or the cam sensor.

Finally got around to checking EGr valve, Black soot all around sides indicating a donein gasket. Went to undo the 3 torx scews and 2 of them were snapped off. As I undid the last one it snapped too woopeee! Got new screws tap handle and tap. Tried to drill out the holes and snapped 3 drill bits. Is this stuff titanium or what lol.

Off to the wreckers in hopes of finding a new plate. I'll keep you posted.