I had a 3.9L that needed a timing chain/ to be freshened up so I...

I bought a junk yard motor, it was bad (Found out after it was in the truck) wasted my nice gaskets and a lot of fluids.....

Then I bought a new re-manned 5.2 used the oil pan etc off the bad motor.

Installed....
Melling HO oil pump
JBA headers (non egr)
M1 Intake (non EGR)
Jegs HV coil
Mopar Performance PCM
Electric Fan conversion
New crank sensor (crushed the old one pulling the motor)
HO alternator (damn nut snapped off the rectifier on the old one)
New fuel filter
Plugs/ wires/ cap/ rotor
Magnaflow 3" cat
Magnaflow 40? series 3" muffler


So it stumbles when it wants to, and runs fine when its cold, drove it about 100 miles so far and now it is acting like a turd. It backfired/ popped so loud it sounded like a rifle going off. The timing was set at 0 when installed after I took the video I attempted to turn the the distributor a little counter clockwise (advancing?) and it seems to drive a little better but... it still would shut off and die while driving.

For ****s and giggles I sprayed down the, intake, vacuum lines and fitting, nothing.... swapped the IAC motor..... still shut off... swapped the TPS, and guess what it still shut off.

I don't have a fuel pressure gauge but the line has pressure when I relive it, I went down the rail and unplugged/ re-plugged each injector, they all appear to work.

Not to long ago with the V6 it received a new O2 sensor.



I found out I leave this week on orders and PCS almost immediately after to Nevada from Washington DC, If I cant't figure this out by mid day tomorrow I'm going to have to plea a local shop to look at it if it can make it.... PLEASE HELP!

The EGR junk is still in place and hooked up, but it no longer has a feeder from the exhaust or a turtle on the plenum.

 

The old y-pipe is a little stretched out from the old headers so it leaks, I need to get it running well enough to drive it to a muffler shop that can make a new one/ or shave the old collectors.


FYI if you put a v8 and JBA headers in a gen one 2wd your going to have clearance issues with the passenger side control arm.

The idle seems smooth but very low 400-500rpm

 

Have you tried replacing the temp sensor? Some have 2 of them and if yours has 2 try replacing the one with just one wire. It tells the pcm the temp for when its cold. Once it warms up the pcm looks at the 02 sensor to adjust the air/fuel mix. With a exhaust leak before the 02 that could cause the 02 to read incorrectly. Another thing is you said you turned the distributor but all that does is adjust the fuel timing. The pcm adjusts the ignition timing. Also check the part numbers for the v6 and v8 02 sensor to make sure its the same part number. It sounds like a ignition timing problem since it is back firing. Hopefully this will help a little.

 

I didn't see a diagnostic instruction in the Haynes manual for it, I pulled the wire just to see if it tripped any lights, or altered the operation of the motor..... but it dies just the same. I will try and run to the parts store as soon as I'm off duty.

Any direction or feedback is appreciated!

 

UPDATE

I died trying to get the parts... no spark, wouldn't start happened a block from home heard a faint pop in the exhaust and it gently cut off.


Wouldn't restart had a old plug and wire in the truck and hooked it up, no spark from coil.


Pushed it home checked the harness for continuity between the coil and computer, crank sensor, and hal effect sensor in the distributor.... all had continuity.

Plugged it back in, nothing... and let it sit, then it started up like nothing happened, jiggled every connector and inch of the harness I could to no avail I could not get it to shut off...

This is such a damn frustrating issue....

 

check the ignition coil. and the notorious splice under the the relay box.

 

Have three coils, the new one is on the motor. And I checked the ground wires for resistance they all sat about the same... if the splice was bad shouldn't it create more resistance. And how it's so intermittent blows me away.

 

Yeah definitely check the splice under the PDM first.

 

I would repair the splice myself to know for sure it is fixed and isnt causing any problems. There has been a ton of people that have had intermittent issues caused by the notorious splice.

 

Crank Sensor? When I swapped to my manual the truck idled for 20 mins or so then suddenly died and had no spark. The crank sensor which was new like yours was rubbing against the flywheel and eventually wore through itself. Just something to double check.