We just put a new 360 in the truck and when we first started it it’s having a misfire (only when it runs bad) backfires shakes everything. It comes and goes like it can’t make its mind up where it wants the timing to be. And it keeps throwing the famous p1391 code. I have replaced everything that sends spark to the plugs. I have changed both crank position and the cam position sensor twice. Put a new pcm in it same thing. When it starts doing it the tac will just jump everywhere but like I said comes and go. All grounds and connections are good. Can someone please tell me what I can do to get my truck back please.

 

P1391 Intermittent Loss of CMP or CKP
What brand sensors are you using? Also did you adjust the fuel sync?

 

I used part house brand then I went with mopar it self and no haven’t messed with the fuel sync.

 

Get the fuel sync set. It's a fancy term for injection timing. The PCM controls ignition timing. The cam sensor adjusts injector timing when you move the distributor. You'll need a good computer to access fuel sync, a code reader won't do it.

 

Yeah somebody mentioned to me that I need a DB our skin tone only person I can find around where I live is a dealership but I’ll give it a shot I appreciate the help this is been stumbling me I’ve never really owned a mopar

 

Sounds like pretty similar issues I had when I installed my new engine almost 5 years ago. I ended up installing my distributor in wrong based on my own prior knowledge. After help from the forum I got it running well enough to hit the muffler shop then the dealer to tune the fuel sync.
HeyYou ended up helping me with that one I went back an quoted it. Maybe it can help you
here

 

I want to start with, Ive never owned or worked on a magnum engine.....
That being said, I do have one thought, and again, if im off base, please tell me..
IF., the fuel sync is out, and it has not been adjusted, could the problem be a stretched timing chain?
My reasoning with this is as follows. The crank sensor is based off of the flywheel, and that adjustment never changes.
The cam sensor is tied to the camshaft "through" the timing chain.... That ties to the crankshaft.
If it stretched the 2 will no longer be in sync.
Just a thought.

 

The timing is all where it needs to be that was the first thing I checked. I even pulled the timing cover to verify cam timing it’s all right. It runs just has no power and runs bad. I’ll give the fuel sync a try and get back with y’all. Appreciate the help.

 

Definitely sounds like timing to me as well. I just wanted to add that my truck ran pretty similar an the distributor was completely 180 out. The guys on here were surprised that it even ran that way. Some even said it wasn’t possible. Shoot some probably still say that lol. But it very well did. I just wish i would’ve had a scan tool then to see what codes came with that issue.

 

well I’m still new to dodge engines and the first time I did have it 180 out wouldn’t run at all. But while we are on timing the Balancer has multiple marks on it as well as “dents” on it with marks on it. I used the right mark for tdc. Would timing make the tach do that? I posted a video of it doing it. I’ll tag it again