2001 Dodge B1500 van, 3.9L V6 with 118,000 miles. I have what I think might be a fuel system problem, but I don't know how to trouble shoot it. Engine is running fine then chokes, backfires, barely runs or moves with full or pumped throttle. Shut it down, starts right up and will run on for a short distance, then begins same all over. Does not exhibit problem from a cold start, but no way to determine trigger point. Suggestions?

 

have you check your fuel pressure? are your injectors working properly?are you getting any spark from the plugs or wire?

 

Does it do this with a full tank of gas or only when it's a half tank or less?

 

Took your advice, fuel pressure is right on target. Did the code reader thing and got five circuit voltage problem reports. Two H02S heater control low, two 02S low (HO2S sends to O2S), and Evaporator Emission System Purge Control Circuit. Think I know the problem, but access makes it a hard fix. Prior to the current trouble had a catastrophic belt failure when the alternator froze up on the interstate. Now that I'm looking, I see two crimp splice repairs in the the wires going to what looks like part of the sensor arrays. Both are right above the belt path. Methinks the mechanic did a quick a dirty to get the truck back on the road. My bet is one or both crimps are bad. But I can't get the @#$%& joint connector apart. Otherwise I have to take most of the hoses and pipes off the top of the engine just to get to the terminating ends of the spliced wires. Any Suggestions?

 

I have a suggestion - do the PITA hose disassembly and get the repair job done right with either heat shrink butt-splices or heat shrink tubing covers over soldered wires. Not fun, not easy -- but correct.

 

Thanks, Rusty. I'm with you, I only trust automotive rated connectors or soldered splices. This time around I was able to get my crimping tool onto the crimps and reset them. Cleared the codes from the computer and started over. This time four of the five circuit faults did not come back, and I'm left with the Evap Emissions Purge Control Valve Circuit. The backfiring, barely chugging along engine conditions are still there, but only one circuit to track down. More damage from the belt failure I guess. Probably should move this thread over to Evap Emissions etc. Still need Ideas and will do the correct repair with the crimps.

 

Yeah, the problem with those open-end butt splices is they let moisture in and the wire corrodes. Even if you wrap them with a good electrical tape like 3M they still fail eventually. I really like the heat shrinkable butt splices; after you crimp them you point a heat gun at them for like 15-20 seconds and the ends close up and fuse with the insulation on the outside of the wire to make a weather tight seal. Put a length of convolute on the wire bundle and boom you're done.

 

my 1998 b1500 3.9 does the same thing, hope you figure it out. i've tried a tune up. plugs, wires, cap, rotor, pcv valve, air filter. same problem and i' ve never had a catastrophic belt failure. im starting to think theres something in the tank blocking the pick up on occasion and causing this. i'll be dropping the tank as soon as it warms up around here. please let me know if you figure anything out.