Hard start after knock sensor replacement week after

[Myronroy]

2008 Dodge Ram 1500 bighorn Hemi

Would anyone be able to help me make sense of this? DTC codes P0325 and P0330 are on, which means both knock sensors (bank 1 & 2) are on. What could cause this issue?

I also have another issue where it takes longer than it should start. Could this be caused by these bad knock sensors? I think if they are malfunctioning it could alter the timing a bit, maybe that's the cause of the hard start? Are there any other known problems for these gen 3's that could cause a hard start or a longer crank time before it starts?

Plus both knock sensors are new and both codes are back now

 

[Atcer2018]

2008 Dodge Ram 1500 bighorn Hemi

Would anyone be able to help me make sense of this? DTC codes P0325 and P0330 are on, which means both knock sensors (bank 1 & 2) are on. What could cause this issue?

I also have another issue where it takes longer than it should start. Could this be caused by these bad knock sensors? I think if they are malfunctioning it could alter the timing a bit, maybe that's the cause of the hard start? Are there any other known problems for these gen 3's that could cause a hard start or a longer crank time before it starts?

Plus both knock sensors are new and both codes are back now

Hi, help me follow along. Did you have the codes before the knock sensor replacement? Are the knock sensors OEM? Non OEM sensors can be problematic in our trucks. When the knock sensors were replaced were they positioned in the same orientation as the originals? Placement is very important with knock sensors. Off too far in one direction will cause problems. Now most importantly, were they torqued to factory specs? If I recall correctly it’s like 100 inch pounds of torque and they have limited variance on the spec, something like + or - 2 inch pounds so you’ll need a well calibrated torque wrench. I’ve only ever replaced two knock sensors and it’s rare both go out at the same time as one is for the intake bank and one for the exhaust bank. They are independent of each other so both tripping a code at the same time is suspicious.

 

[Myronroy]

They were both replaced at a shop and I believe they’re aftermarket and I bought the truck off my father in law and he said that the check engine light came on and he took it to a shop and they scanned it and said it was the knock sensors and they replaced it and not to long after that the check engine light came back on and then along came the hard start with it and now I’m trying to fix it

 

[Atcer2018]

I’m sorry you inherited that mess. Sounds to me like you have to make sure the knock sensors are working properly before you start throwing parts at it. To get a good diagnosis those sensors will need to be checked out. It could very well be they failed at different times and your FIL wasn’t specific in his description or possibly ignored the first one for a while till the second one went out. I have only replaced two and not two on the same vehicle but a double failure isn’t out of the question. Unfortunately our trucks are more sensitive to some aftermarket parts than others. Knock sensors are one of those parts. If you’ve ever seen one you scratch your head and wonder why as there isn’t really anything special about them. The placement of the sensors is critical and the torque spec is also important. Too tight and bad performance. Too loose equals same bad performance. You could ask the repair shop if they warranty their work from the last replacement or try and tackle it yourself. I think you’re on the right path as a bad or misaligned/torque knock sensor will retard the timing and cause a hard start.

 

[Myronroy]

He did take it back to the shop for them to warranty it but they couldn’t fix the problem and so now I just need to figure out how the knock sensor placement are supposed to be and replace both of them again and go from there because that’s the only codes that are there and I looked at the wiring and all looks good but I did see that the shop put a heat wrap around the knock sensor on the driver side though I’m not sure why

 

[Atcer2018]

He did take it back to the shop for them to warranty it but they couldn’t fix the problem and so now I just need to figure out how the knock sensor placement are supposed to be and replace both of them again and go from there because that’s the only codes that are there and I looked at the wiring and all looks good but I did see that the shop put a heat wrap around the knock sensor on the driver side though I’m not sure why

I’m not familiar enough with your model year to know if that heat wrap is supposed to be there. If it’s metallic it may cause a bad signal. Could try removing it. On my 2018 I have the V6 and I know while replacing my oil filter housing the knock sensors in the Pentastar have notches formed in the block to ensure proper alignment. If your hemi has that it can help orient the sensor. If not you’ll need a service manual or someone who has the same year and engine to visually inspect. The knock sensors are expensive for your truck. I looked them up and one is $115 and the other $105. That’s crazy as my sensors are $25 each. I’d want to check them out before you throw $225 worth of sensors on it. Best I can offer is try a different shop or get a manual and test them out yourself for resistance, voltage and continuity.

 

[Myronroy]

I was going to try oriellys and they’re 20 each there and but I’ve looked the sensors up and I don’t see any of them having the sticky heat wrap on it and I’ll try removing that and maybe loosen up the bolt and and torque it and most likely the mechanic didn’t torque it to spec and probably just snug tighten it

 

[Atcer2018]

I was going to try oriellys and they’re 20 each there and but I’ve looked the sensors up and I don’t see any of them having the sticky heat wrap on it and I’ll try removing that and maybe loosen up the bolt and and torque it and most likely the mechanic didn’t torque it to spec and probably just snug tighten it

Good plan. Make sure your torque ***** is calibrated. It’s not a lot to fasten them down but the amount of under/over is pretty tight on them.