2005 ram 4.7 random loss of power, pulling 7° timing, no clue why. Please help

[krankmotorsports]

Hello yall. I got a real problem child ive never seen before. I drive the same way to work every day. I can 100% feel the power loss. Its the difference in climbing a hill at 50mph at 25% throttle, then next time it takes 80% throttle to get up same hill barely getting to 50mph. Watching data, appears that something is ringing the knock sensors, causing ecu to pull up to 7.5° timing......which kills power and fuel milage. Had a lifter chatter at startup, replaced all lifters no change.....removed, checked exhaust manifolds for warpage, reinstalled with new gaskets and torqued to 25ft lbs.....no change in knock signals or running... ive NEVER seen anything like this. Fuel pressure is verified under load, fuel trims all appear normal.....all new denso 02 sensors. New coils. Plugs. Intake manifold is sealed. New iac. New tps. New intake air temp sensor. New map sensor. New cam sensor. New egr valve. New purge valve. New pcv valve. Catalytic converters are both clear and functioning. Can anyone help?? I would greatly appreciate it. 2005 ram 4.7

 

[jws123]

what is the mileage on the truck? and have the timing chains tensioners and guides been replaced yet? every single 4.7 needs this done at least once due to age the plastic gets brittle.

 

[krankmotorsports]

I have not done timing. Haven't seen a need to it runs perfect except when it does this. 130,000. I'd like to add, I have noticed and verified it last night, the truck seems to run perfect if I unhook the battery, clear pcm. It'll run for about 15 mins amazing, then slowly start to get worse. Tell me its a sensor.

 

[jws123]

Im not saying its 100% your issue but with the 4.7 the timing can be 1-2 teeth off on one bank and it will still run. I had a 2005 dakota same exact engine/setup when it warmed up it would BOG like hell no codes ect. Eventually I took the drivers side valve cover off and realized it was 2 teeth off. New timimg kit and she ran like a bat out of hell after that. The guides get brittle with age. Also how did you verify the cat converters are not clogged? thats another thing that usually shows up when the vehicle gets warm/under load.

 

[krankmotorsports]

When I had exhaust manifolds off I looked inside of them. I was expecting to see melted cats but no. I figured since its an intermittent issue timing was ruled out.

 

[krankmotorsports]

My way of thinking is that the knock sensors are clearly showing activity, I'm not sure what's causing it but I'm guessing that's the Smoking Gun considering it's pulling seven degrees of timing when it happens

 

[jws123]

My way of thinking is that the knock sensors are clearly showing activity, I'm not sure what's causing it but I'm guessing that's the Smoking Gun considering it's pulling seven degrees of timing when it happens

What kind of fuel are you running do you hear any pinging when under load?

 

[krankmotorsports]

What kind of fuel are you running do you hear any pinging when under load?

87, but when I noticed this issue I did put 94 in it and it didn't change anything. Didn't seem to anyways

 

[krankmotorsports]

What kind of fuel are you running do you hear any pinging when under load?

I dont hear anything but truck has aftermarket exhaust might not be able to.

 

[krankmotorsports]

So I did just verify twice that the truck runs perfect after you've unplugged the battery for about 10 minutes. Then about 10 minutes after driving it it starts running like s*** again, which tells me it's getting bad data from somewhere but I don't know where everything seems to appear normal..... can anyone verify whether or not the PCM pulls timing after a reset? Like is there a specific drive cycle it has to do before it starts pulling timing? I would think it would do it immediately to prevent catastrophic damage