4.7L misfire
#1
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Well, this doesn't just belong to the 1st Gen durango forum even though that is what it is happening on. This is issue with my 2000 4.7L engine, getting a P0307 cylinder 7 misfire CEL. So, I went with the spark plug (replaced them), the coil on plug (replaced it), cleaned the fuel injectors and still got the misfire. Took it to the mechanic and they tested. Found that the fuel injectors where working, and getting spark but found that compression on cylinder 7 was 50 psi. So they recommend an engine replacement. I told them I replaced the engine 40K ago, they didn't realize the engine was replaced, thought the engine had a lot more miles on it.
They tell me it it probably piston ring or burnt valve. Both look like it is an engine replacement or major engine work to fix it. I did take the valve cover off and the rocker arm is still in place. Was hoping for some way to salvage this, is it possible that a bad lifter could cause a misfire (low compression)? Or would a faulty llifter just prevent the valve from opening all the way (or failing completly and causing the rocker arm to fall out) and not have anything to do with compression? Thanks for any thoughts on this.
They tell me it it probably piston ring or burnt valve. Both look like it is an engine replacement or major engine work to fix it. I did take the valve cover off and the rocker arm is still in place. Was hoping for some way to salvage this, is it possible that a bad lifter could cause a misfire (low compression)? Or would a faulty llifter just prevent the valve from opening all the way (or failing completly and causing the rocker arm to fall out) and not have anything to do with compression? Thanks for any thoughts on this.
Last edited by mopman42; 06-22-2020 at 09:29 PM.
#4
#6
#7
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Ok, looked at some video's and think I can do this. I am a little nervous about the timing, maybe if I only do one head it will be easier but not sure on that. Just need to figure out if it is valve or if it is piston issue. Don't think I'm capable of fixing if it is a ring.
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#9
#10
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for the tool you need a flat iron and 2 screws I will show you a photo of the tool that I made. with it it is much easier to unscrew the pinions of the camshaft and to tighten them. for the timing belt. the main one is to call the crankshaft well and then the 2 pinion where it is written "v8" must be horizontal. before dismantling you must put the pulley on the mark at the bottom right of the engine.