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  1. #1
    Cherokee2004's Avatar
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    4.7l v8 cylinder heads

    Just recently had my V8 cylinder heads resurfaced and installed with new head gasket and new water pump. after putting this all back together the vehicle won't turn over now, not even getting a spark. Any ideas of what I missed or could be the issue now ?


    Any help is much appreciated.

  2. #2
    k-2's Avatar
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    Re: 4.7l v8 cylinder heads

    BASICS -
    Wont crank - In P or N -?
    If not cranking it won't spark.
    KOEO
    coils have 12v?
    Injs have 12v?
    CODES?

    Tell what year, vehicle and we can get wiring dia to work from

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    Re: 4.7l v8 cylinder heads

    first is your static timing properly set?

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    Re: 4.7l v8 cylinder heads

    It started now, but dies. Getting 4 error codes of
    P0353, P0354, P0355 and P0358. All ignition coils issues. Highly doubt that they all went bad at once so im thinking a bad connection or fuel pressure issue is causing these codes to come on. Just put back on the heads cylinders and thinking that possibly since the battery was disconnected that could posdibly be an anti theft feature, but doubtful. More leading towards a fuel issue considering the vehicle wasnt running/started in 3 weeks. 2004 Jeep Grand Cherokee Overland V8 4.7 L

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    Re: 4.7l v8 cylinder heads

    put a fuel pressure gauge on it post PSI.

    Check connectors at coils - tight and is there 12v KOEO?

    You do have a scanner? It is capable of showng ALL codes?

  6. #6
    JPNinPA's Avatar
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    4.7l v8 cylinder heads

    I would verify spark plugs are ok no external arcing marks or damage and the boots are intact. Check the connectors and wires to the coils.
    Also check that all plugs into the PCM are locked and tight.

    Regards,
    JPNinPA

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    Re: 4.7l v8 cylinder heads

    The battery was taken out and disconnected for about 3 weeks while the head cylinders were being worked on. Whats the possibility of it being an issue with the PCM and that just needs reflashed ? Checked all the wires, connnections and fuel pressure is fine. Starts, but dies shortly afterwards like the PCM isnt letting fuel in to keep it running. Scanner keeps showing different codes each time as well. Im 99% think the PCM needs reflashed. Any other thoughts ?

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    Re: 4.7l v8 cylinder heads

    Post the codes


    Regards,
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  9. #9
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    Re: 4.7l v8 cylinder heads

    Its a 2004 Grd Cherokee V8 4.7L It now stats , but idles really rough an wants to die sometimes. also if tried driving it doesn't have much power and barely moves.

    codes that come up are for misfires of the cylinders and the are random at times. thinking it is a timing chain issue so having it retimed and if that makes a difference .

  10. #10
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    Re: 4.7l v8 cylinder heads

    Thanks JPNinPA,

    The spark plgs are new and checked all wire connections to them and to the PCM. My brother and I are thinking the Timing Chain is set incorrectly and needs reset of which is being done now. hopefully this was what was causing these misfires to the cylinders and not giving it any power to move and idle rough. anything else I should check ?

    maybe the following:
    IAC
    TPS
    CRANK SENSOR
    VACUUM LEAK
    LOOSE PRESSURE PUMPS
    VAPOR CANISTER

  11. #11
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    Re: 4.7l v8 cylinder heads

    Are you using a scanner ?

    I am thinking a chain incorrectly installed would cause timing issues and set correlation (sync) codes. And the scanner could show offset. let us know.

    Maybe a scan and post all codes.. Look at live data - ECT, FT's, MAP, TPS, o2 voltages, and finally fuel pressure.

  12. #12
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    Re: 4.7l v8 cylinder heads

    The only code that shown is P0354 for cylinder #4, possibly a wiring issue with that or a bad coil. Also the fuse #6 keeps blowing so might be a short someplace and will be checking all the grounds connections as well now. Would timing issues cause the fuse to blow ?

  13. #13
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    Re: 4.7l v8 cylinder heads

    Are you using a scanner?

    Fuse #6 underhood or in cab fuse box?

    No to timing causing a fuse to blow.

    SWAG - wiring issue - pinched grounded harness -

  14. #14
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    Re: 4.7l v8 cylinder heads

    Yes, also was diagnostic done at the Jeep dealer. The #6 fuse is the small yellow one in the fuse box under the hood. I will check all the ground wires for any kinks and possibly any contact on them that shouldnt be. Thanks.

  15. #15
    k-2's Avatar
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    Re: 4.7l v8 cylinder heads

    I do not think you have a problem with grounds - more likely a power feed ie coils or inj. on
    bank 2. The coil for cyl 4 is a clue.


    Look at diagram confirm which fuse - #6 is a 30amp and a major circuit - ASD is the main circuit for jeep.
    Attached Thumbnails Attached Thumbnails 4.7l v8 cylinder heads-pdc.jpg  

    Last edited by k-2; 06-01-2017 at 08:11 PM.

  16. #16
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    Re: 4.7l v8 cylinder heads

    I redone the timeing got all the marks where there suppose to be also the links on the chain. But know it wont even start turns over but no start. Also when reconnecting the battery if i connect the ground first then the positive i get a spark does that mean there is a ground some were or a hot wire on that shouldnt b with the ignation off any thoughts greatly appreciated thank you inadvance.

  17. #17
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    Re: 4.7l v8 cylinder heads

    see post #13 and #15.....

  18. #18
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    4.7l v8 cylinder heads

    The spark may mean you have a draw somewhere.
    You can connect a multimeter reading current between the negative terminal snd negative cable connector. The current should be 50ma or less. From there you could start pulling fused to find the circuit at fault. After that inspect all connections and wires in that circuit. The radio is the only item that pulls moderate ma current with the key off.




    JPNinPA
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  19. #19
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    Re: 4.7l v8 cylinder heads

    ok, Sorry for the long delay in responding back. Took the vehicle into the shop and it was diagnosed and no codes came up. Shop did say that the left side (driver side) had little to no compression ands says it needs a new camshaft as the left side is slightly bent, new valves #4 is damaged and then retimed. Hopefully will do the trick and will run again. As anyone heard of the quality of Car Parts Wiz (CPW) off of Ebay as to whether they are good pats or nots ? thanks

  20. #20
    JPNinPA's Avatar
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    Re: 4.7l v8 cylinder heads

    No clue

    I use rock auto.


    Regards,
    JPNinPA

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