So after swapping in a new engine I had what i assumed was a timing issue. Engine sounded sick, and would bog down and die if revved past 3500 rpm. I took it to a shop and had them do a factory reset on the timing and it ran great for a couple days. Now about a week later it feels like it has reset again. Is there anything that would cause the computer to forget timing changes? There is a graph attached showing timing advance vs throttle. Not sure if this much advance or variability is normal.

 

Do you mean fuel sync? Did you use the old sensors from the old motor? Are you getting any codes?

 

No codes. And I think the only sensor I didn't use from the old motor was the crank sensor. From what they told me they reset the ignition timing to factory settings

 

Ignition timing isn't adjustable. You can turn the distributor to your hearts content, and all it will change is INJECTOR timing. That needs to be fairly close to 0 (plus or minus 7 degrees) for the engine to run properly.

Unfortunately, Dodge didn't see fit to include a knock sensor in the electronics suite on these engines, so, timing is purely computer controlled via tables. That said, your timing should never get down to zero.......

 

The drop to zero was when the engine died. Prior to that it was all over. The shop had it blugged into the computer to adjust it. It actually ran really well until the next day

 

I would take it back to the shop and have the set the fuel sync. With the new engine that was installed - was the distributor new or was it reused from the old motor? I ask as distributors can also go bad over time, too.