CC CLeaner results (was: code 43/P0307 thread)

Rotsa ruck w/Rita! After things settle down, try one more CC treatment. If you had a LOT of carbon, one treatment may not have been enough... don't spend any more $$ until you try this or do the injector swap as Denny suggested.

Mike

Thanks Mike. We dodged a big bullet w/Rita. There's still very limited availability of gasoline right now (2:30 PM Sunday) but the major highways coming into the city are all clear. We're hearing reports of major traffic jams along some of the smaller connecting routes that feed into I-10 and I-45. The trick to use the little back roads was a great idea to bypass the bottlenecks and get out of town, but coming back in all the major freeways are wide open and it's the little two lane roads that are jammed up.

97 Ram CC/SLT 5.2L 80,800 miles. Compression check was only on a cold engine and showed no probs, all cyls 130 psi or better, cyl 7 was not the highest but was among the higher ones. The dealer (sublet) replaced the CAT and an upstream O2 sensor at approx 65,000.

The problem seems limited to occurring only at very low RPM, below 1000, as in when decelerating to a stop and/or sitting idling at a traffic light. Hold your foot on the accelerator pedal to hold idle at or above

1000 and the P0307 won't occur. Engine is up to normal op temp when the event occurs. Doesn't happen immediately at low idle, but will occur sometime within the first minute of an extended idle period. Happens idling in gear as well as idling in neutral or park. 52 psi fuel pressure.

The problem has been ongoing for 18-20 months, but initially we didn't realize it was happening only during decel or at low rpm. Also at first flushing the injectors would provide some extended relief, usually several months at a time. We replaced the coil, plugs, wires, rotor, IAC, did TSB

18-48-98 and now the CC cleaner. Unrelated, also replaced battery and air cleaner.

Even now whenever the code is cleared the truck runs like a scalded dog, no drivability issues at all, excellent power, smooth shifting and no surging. With P0307 stored it is slightly rough idle and some minor noticeable loss of power.

Ok, the compression check was done on a cold engine and it was ok. This will be a bitch but warm the engine up good and retest #7 compression. Compare the warm reading to the cold reading and see if they are still in the same range. I got this sneaky feeling a valve is sticking sometimes.

Denny

Is it still necessary to pull all the plugs just to retest #7 while it's hot?

Just curious here.. what's the going rate these days for a valve job/top end overhaul on the mopar 5.2?

Nope, I'd just do the 4 plugs on that bank.

It's been a while since I priced one out but to do both heads is about $1,000 by the time the machine shop gets added on

Denny

Leave 'em... just pull the ASD and fuel pump relays from the power distribution center. This way, the fuel pump won't run, and the injectors and coil won't fire.

Follow-up

I repeated the CC cleaner routine again last weekend. While the first dose improved things, the second treatment -seems- to have solved it. This time I also let it sit overnight before cranking it up again. No more P0307 at all in a whole week of in-town driving. For grins I also poured 20 ounces of Techron in the tank.

Bottom l>Miracle stuff.