[Northstar97hell]

I had code p0340 pop up so I changed the CMP and both CKP's. Engine still idles rough though when I get it up to speed it seems to go away. Reading the forums I see that it is supposed to have a "relearn" procedure performed. I take it to a Chevy dealer (mistake) he tells me there is no relearn procedure for a 97. Is this true? If no relearn procedure how hard is it to time the N*'s?

 

[MoistCabbage]

Always list code definitions along with codes.

P0340 - CMP sensor circuit

Was the engine running rough before the code was set?
Is the code still current?
Any other codes?

Timing is controlled by the PCM and not adjustable.

There is a relearn for the CKPs, but it's almost never necessary. If there was an issue you'd be getting a related code.

 

[Northstar97hell]

Just bought it. Ran fine for about 3 days, then it started the rough idle. Only code is the 340.
Could PCM be bad?

 

[basscatt]

Just bought it. Ran fine for about 3 days, then it started the rough idle. Only code is the 340.
Could PCM be bad?

----------------------
did you use genuine ACDelco sensors -
or el-cheapos?

 

[Northstar97hell]

Took to Cadillac dealership they had it for 3 days diagnosing.
1st they thought it was ignition module, put new one on did not work. No charge.
2nd PCM, new one on did not work. No charge.
3rd diagnosed timing issue. Remove engine and fix. $2,200.00
So this is the summary: Chevrolet dealership fixed head gaskets in January 2013 but put it back together wrong. Little lady I bought it from went to a nursing home in March of 2013, the car sent her over the edge!
Dealership in Springfield, MO. took great care of us and I am really impressed by their dedication, would highly recommend them to anyone in need. While they had it out they checked everything over and gave it a clean bill of health. 96,000 on it and the journey begins.
Thanks to all that helped out.

 

[MoistCabbage]

So there was a valve timing issue? That would cause running issues constantly, not intermittently.

 

[Northstar97hell]

The issue continued at any speed just not as noticible. Apparently there is an RE and RI timing setting, I may have terminology wrong, and they were reversed. Does that make sense?

 

[Submariner409]

If the cams and/or timing was "reversed" you would have certain mechanical mayhem. Something's not right, though.

The RE sprocket also has the pulse trigger button for the CMP hall effect sensor - timing and rotation TDC reference.

RE, RI, LE, LI - Right/Left Exhaust/Intake sprockets.

 

[Northstar97hell]

According to Cadillac dealership both exhaust cam gears installed 180 deg out. and replaced ignition coil. The only issue I still have is the service engine light is still on. Any thoughts?

 

[Submariner409]

Four coils, specific coil-to-plug wiring order.

Here's your system.