5.7 hemi issues

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Leroy Sanchez

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I have a 2012 ram 1500 Laramie with a 5.7 hemi. I recently had my cams and lifters changed along with the oil pump heads, water pump, timing, chain, spark, plugs, coils, injectors, you name it. Well, I have had to take it back to the shop three times due to the fact it was throwing several codes and still had low oil pressure 12psi. Along with a very ruff idle and a very pronounced tick on the passenger side during start up that goes away almost immediately. However, I am still throwing a misfire for cylinder eight and can’t for the life of me. Figure out what the hell it is. I pulled my valve covers checked the lifters ran a borescope in the cylinders to make sure there was no damage. I took it into a different shop. He suggested Unloyal change and to add Lucas after doing this. I am still having the issues. I would appreciate any help on what could be causing this.
 

jws123

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Check the pushrods on cylinder 8 make sure they are clicked in all the way very common when re installing for it to not seat all the way i do it almost every time lol. as dor the oil psi i would verify it with a mechanic guage and then change the sensor.
 
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Leroy Sanchez

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I change the oil pressure sensor already. Still having that issue. I will definitely double check the oil pressure with a gauge and thank you for your help. I didn’t even think about the push rods.
 

jws123

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I change the oil pressure sensor already. Still having that issue. I will definitely double check the oil pressure with a gauge and thank you for your help. I didn’t even think about the push rods.
If the oil pressure is still low with manual guage change the oil filter could be messed up not uncommon.
 
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Leroy Sanchez

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So I did another oil change added Lucas to the mix and it seems to have helped my oil pressure is staying around 20-22 psi at idle. However, I cannot for the life of me figure out what is causing the misfire in cylinder eight. I pulled the valve cover and check the push rod. Made sure it was clicked into position. Everything looks good. But I it is still throwing the code.
 

indept

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It could be a bad injector or coil (Even though they're new), each could be swapped with another cylinder & see if the code follows. With all of that work, have you checked compression since the rebuild? Did you use quality parts or did you go for cheapest?
 
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Leroy Sanchez

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Swapping everything was the first step that I took. Checked the compression 160 to 165 on all cylinders. All Mopar parts. Check the cylinders with the borescope. No damage to the cylinder walls. Everything looks great. But I continue to get a misfire in cylinder eight.
 

indept

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Swapping everything was the first step that I took. Checked the compression 160 to 165 on all cylinders. All Mopar parts. Check the cylinders with the borescope. No damage to the cylinder walls. Everything looks great. But I continue to get a misfire in cylinder eight.
Have you verified the injector & coil are getting their signals, it's possible the wiring may have been damaged during the rebuild.
 

Dusty

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Swapping everything was the first step that I took. Checked the compression 160 to 165 on all cylinders. All Mopar parts. Check the cylinders with the borescope. No damage to the cylinder walls. Everything looks great. But I continue to get a misfire in cylinder eight.
Have you connected a scan tool and recorded all codes? If so, what are they?

Regards,
Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 83966 miles
 

Rob Friend

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What do you mean by heads being done? I had a #5 misfire for a long time, thought I did everything until I remembered to do a leak down test and had a bad intake valve. I pried up on the valve and it sealed up. I replaced the head and all good. Good for thought
 
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stock 5.7 with 6.4l cam and MDS delete
Not much to add here. I think the thread has almost covered it all.

However, the rear of the engine main harness is a bad pinch point. it can cause intermittent problems and, if gone long enough, even sever a wire that can cause a misfire. Also I have removed injectors and actually sprayed them on both sides (top and bottom) with fuel system cleaner.

When i do top end engine jobs I always try to rotate the push-rods as I install them. Yes they do need to be snug but not to the extent you cant turn them. This is a way that you can verify that they are actually in their seat or not. Trying to turn them before the initial startup and as you are reassembling the engine can sometimes make them drop into their seat.
Just paying attention as you go back together to the little things can sometimes prevent issues.
NOT SAYING YOU DIDN'T but just food for thought.

Good luck and let us know what it turns out to be when you figure it out.
 

hardwere

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Having similar problems with my 2014 ram 1500 hemi 5.7. Took it to the dealership for cam and lifters at 112k and they tell me I need a new engine. It now runs worse than when it had a ticky lifter. Has a rough misfire until it gets the idle up to 1k
 

indept

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Having similar problems with my 2014 ram 1500 hemi 5.7. Took it to the dealership for cam and lifters at 112k and they tell me I need a new engine. It now runs worse than when it had a ticky lifter. Has a rough misfire until it gets the idle up to 1k
That could be a vacuum leak. Maybe just a hose or could be a damaged intake manifold seal. Take it back to the dealer, sounds like their problem.
 
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