Have 01 S10 4.3 Removed front cover because of oil leak. Installed new cover reused crank sensor. While I was in there installed timing chain tensioner. Truck has 80000 on it didnot change timing chain and sprockets. I now have p0300 code. Checked timing retard with scanner -3 degrees. I was thinking I had timing chain off a tooth but I would be out more than -3. Is -3 degrees close enough? Must it be 0 Could installing a tensioner on a chain with this much milage on it change timing enough to give me a p0300 code? Installed new fuel pump Still donot have 60 PSI at idle. New cap rotor plugs plug wires. p0300 code started after I changed front cover and added tensioner. Engine runs great other than this.

 

Whenever the timing cover or crankshaft position sensor is moved, removed, replaced or disturbed in any way, the crankshaft position sensor relearn MUST be performed with a capable scan tool. The relearn syncs the sensor with the crankshaft. If the relearn is not done, the PCM uses the sync data from the last relearn, which is now incorrect. The PCM uses the crankshaft position sensor data for cylinder misfire identification, (among other things) and the old adage applies: junk in, junk out. After the relearn is complete, recheck & adjust camshaft retard to zero degrees, plus or minus 2 degrees.

If fuel pressure is 60psi or higher at idle, there's a problem. GM does not publish ANY engine running fuel pressure specs for this engine, far too many variables involved. Key ON, engine OFF, fuel pump running: Must be 60psi to 66psi and must remain above 55psi for at least 10 minutes after the fuel pump shuts off.

Cap rotor and plugs.... make sure they're all AC Delco, wires just need to be a good quality name brand, not a store brand. Put a dab of silicone dielectric grease on each terminal of the cap, inside and out.

 

Thanks for the reply. Ive gotten so much conflicting info on this. Some say they never had to do relearn. I thought since I didnt replace sensor with new one it wasnt needed. I Emailed local dealer to see if they can do relearn.

 

Conflicting info???? More like WRONG info. If someone told you they didn't have to do it, they're only fooling themselves, don't let them fool you! If the relearn is not done, the engine will run, but you can expect ignition timing, injector timing, cylinder misfire etc all to be incorrect, and NO service engine soon light! What I explained in post #2 is straight out of the GM "dealer issue" factory shop manual.