Hey Dodge Forum!

I have a 2002 Dodge Ram Van, 3.9L with 220K or so miles on it and recently hit a problem I can't solve. I had to replace the PCM due to "no bus", it ran ok prior to changing it with an occasional P0304 code, engine miss but the PCM died. After changing the PCM I'm getting 0443 0132 0138 codes, I also pulled the evap canister to check for vacuum leaks. What I've done so far is replace the vacuum solenoid and both O2 sensors, the codes still persist. I tried blocking the vacuum coming off the intake that goes to the solenoid thinking it would bypass that evap system, at least let me know if there was a vacuum leak further down stream but there is no change, the solenoid is getting voltage and I heard it clicking. I'm a bit stumped at this point and don't want to keep throwing parts at it. I'm wondering if the van PCM is slightly different or needs a programming specific to the van, the guy I bought it from replaced it once so the issue persisted with two replacement PCMs.

The van starts but when driving starts sputtering and slight backfiring and wanting to stall, It also idles rough. When driving I have to put it in neutral, gun it a bit and then drop it into drive to limp it around. It seems to get worse after bringing engine up to running temp.

Anyway, I thought I'd throw this out to the forum and hoping maybe someone can steer me in the right direction.

 

Check the wiring for the O2 sensors. If you have a scanner, see what voltages the PCM is seeing coming back from them.

 

Thanks. I do not have a scanner, just a code reader.

 

Try temporarily driving with the fuel cap off or loose to see if the engine drives better. If it does the evap vent hose might be clogged. Also, you should test your fuel pressure since the rough idling, driving, and backfiring are all signs of insufficient fuel flow.

 

Thanks. Yep, gave that a try after re-setting ECU, no change but picked up a new code P0037. Funny thing is it does fine until it warms up and then wants to stall, minimal idle and sputtering, rev it for a bit and it goes, so yep, I'll get a fuel pressure tester and see what it says.

 

Downstream O2 sensor heater, could be a blown fuse, or it's wiring could be laying on some metal and got chafed through.

 

Hey thanks again.

I picked up a circuit tester and when I apply the lead to the positive connector of the solenoid it goes solid red. When I apply it to the ground side of the connector it blinks green. When I put a stethoscope to the solenoid it I hear it thumping, it's probably clicking but the stethoscope amplifies the sound. I'm wondering if that ground should be flickering? Is the ECU sending something intermittent or should that be a solid ground? It's still producing 0443 and 0132 codes.

 

Thanks! I picked up a fuel pressure gauge and with key on it sits at 40 PSI, after starting, the PSI is fluctuating very rapidly from 40-50 PSI, I'm thinking it should be more steady or at least not fluctuating 10 PSI. I also checked the fuel pressure with the vacuum off of the intake plugged and it still had the 10 psi fluctuation when running.

 

I wasn't aware that fuel pressure was vacuum modified on these engines????

 

Yeah, I'm chasing a P0443, purge valve solenoid, so I unplugged the solenoid and plugged the vacuum just to see if there was any difference in fuel pressure, thing is the way the PSIs on the pressure jump around and the control wire on the purge valve solenoid flicker like a strobe I just want to take the solenoid out of the equation. Now I'm wondering if the ECU would send strobing like power to the purge vale solenoid based on the strobing PSI readings. I'm using the term strobing because the on the pressure gauge you can't actually see the needle move it's moving so fast, it's just a grey blur between 40 - 50 psi.