I think you are on the right track, though. If it's not running too long at all, then you are likely kicking out on the high side due to the overcharge, which does not let the pressure build up. Note also, that as per Dodge, it *should* cycle some - no cycling is on the diagnostic list as a symptom of undercharging. I note that you are a 2008, and that is the manual year that I was looking at, so the charge figure I posted earlier should be correct. Oh, and the manual also shows that a low size pressure of 20 to 30 PSI at 70 degrees is normal operation - so not sure where you got "low side cuts at 25psi - the factory docs show that this system tends to run on the low end on the low size, with a max low side pressure listed at 100 degrees outdoor of 40 to 50. Have you checked high side pressure? The manual (again, 2008, but should be close) shows a high pressure service port in the liquid line, so you should be able to read it. Considering that a lack of charge can be sensed on the high side, and it's the high pressure that you want to cycle on to protect the system, so it may be possible that you are cycling on high pressure, especially considering the amount of refrigerant that you say that you have put in. Looking there, I also do not see (my search has not been exhaustive, though) any low pressure sensor - only a high side sensor. What caused you to decide to put so much in, and to ignore the spec for the charge? Did the system lose everything, or ? If you lost the works, did you pull a vacuum before recharge?Įdit:: Just checked the 2008 service manual - 30oz is the correct charge for a 6.7. I'm too lazy to go look at my truck, but a quick search indicates that the correct charge should be 1 lb 14 oz, or 30 oz total, so if you truly put in "3 cans and 1lb" you are actually grossly *overcharged*, although I can't understand the low size pressure being so low, unless you have a clogged orifice or some such, blocking refrigerant return to the low side. If you are overcharged, however, you may be cycling on the high pressure cutoff. What is the correct charge, as printed on the label under the hood? Any more or less, and you won't perform, although overcharge would tend to give a higher pressure.
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