2014 4.3L Ignition timing is -8 to -13 degrees at idle.

Mark Duke · February 6, 2023

I have a few issues I'm diagnosing on this truck I traded for - 2014 4.3L. The previous owner said he changed the Camshaft Position Sensor for a P0341 code. That didn't fix it. I pulled the wiring diagram and checked the wires back to the ECM. One of them had high resistance so I changed the jumper harness and the wiring checks good now. I still have the P0341. I noticed something today I didn't notice before. The ignition timing is currently running -8 to -13 degrees at idle. That doesn't sound right at all. I have AllData DIY and can't find any info on what the timing should be. My initial thought is there is an issue with the VVT system. There are exceptions, but I am not a "throw parts at it and hope it fixes it" kinda guy. I want to be reasonably sure what I'm doing before I do it. The truck has a dead miss w/ no codes or misfires noted on scan tool. I feel like I need to solve the timing issue before worrying about anything else. Do you guys have any recommendations on what to check? Is there a procedure for checking the timing? Any guidance would be helpful. Thank you.

Grumpy Bear · February 6, 2023

15 hours ago, Mark Duke said:

The ignition timing is currently running -8 to -13 degrees at idle. That doesn't sound right at all.

It may be a few days, but I'll look at my 2015 4.3 and get back to you. Hot idle, right?

Grumpy Bear · February 7, 2023

@Mark Duke

Hot idle in neutral or park is 4-8*

Hot idle in gear is 8-14*

Cold adds about 4 to each

A/C adds about 4 to each.

It will go negative on decel near the bottom of each gear as much as a dozen. That's TIR.

Hope that was helpful.

Mark Duke · February 7, 2023

Thank you for the info. I knew a negative timing didn't sound right. Now to figure out what the issue is.

CamGTP · February 8, 2023

From what I know on these torque based controllers is that it will pull torque to control the idle. So that means it will pull timing away to help control the idle. If there is a misfire at idle the computer is doing it's best smooth things out.

Does the misfire go away at say 1,000rpm?

Mark Duke · February 8, 2023

It does go away, but more like 2,000 to 2,500 RPM. I was thinking the timing might be causing the misfire. Could the misfire be causing the retarded timing at idle? What data do you recommend I look for with the scan tool?

CamGTP · February 8, 2023

If it takes that much RPM to go away it's possible that a cylinder is lower on compression or there are a few lobes on the camshaft that are wiped out.

Mark Duke · February 8, 2023

I have one of those heat sensing guns on the way. Hopefully it will either confirm or rule out a dead cylinder. Thank you for your info.

Mark Duke · December 19, 2023

I've been out of town working most of the year. This issue has been resolved, but I'm not sure how. I'm going to start a new thread with where I'm at now.