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Time for new injectors?

Discussion in 'LR4' started by Michael Gain, Jun 9, 2020.

  1. LR4FoxsSake

    LR4FoxsSake Full Access Member

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  2. Michael Gain

    Michael Gain Full Access Member

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    @LR4FoxsSake , bottom line: the LR4 hates non-oem coils. It will only stay running when the old, LR coils are installed. According the the indy, the pcm is shutting down spark from the Bremi and Delphi coils because it is seeing a resistance that it doesn't like--no idea if that is the case, but it's plausible.

    So, i have three, brand-new, OEM coils coming this week. Why three? Because it is cheaper than 6, I can test test an entire bank, and if it doesn't work I am only out the three coils (did you know that you cannot return electronic parts if they have been opened and installed?)

    Hopefully, I can report good news by this weekend. On a side-note, I have my rear tire swing out sitting in my garage and ready to install after its voyage from Australia!
     
  3. Michael Gain

    Michael Gain Full Access Member

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    Update:

    Truck loves the new, OEM coils, but misfire remains. New coils went in the passenger bank, and I played with combinations of the old, oem coils on the driver side bank.

    Oh, and the number three injector code returned. I have codes related to the number three cylinder, but with live values, number 5 seems to be the problem..

    Help!!!
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  4. djkaosone

    djkaosone '11 LR4 HSE LUX 5.0L V8

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    Have you tried testing for spark? Do either 1 cylinder or all of bank 1 or all of bank2 at a time, disconnect the fuel injector(s), disconnect/remove the coil(s), remove the spark plug(s), insert the spark plug(s) into the coil(s), plug the coil(s) back into the harness, ground the spark plugs, and start the truck briefly.

    I've used stripped 14 awg wire to wrap around each plug for the entire bank and checked all at once. It also helps to have someone press the Start button while you're looking for spark. Also helps to cover the hood with a blanket to darken the engine bay to see the spark better.

    What you're looking for is spark on the spark plugs and if any of them don't have spark, that means you found a lead to the issue. Now you can swap plugs first, then coils with a known working set to see if you're getting spark.

    If there's still no spark, check the wiring with a multimeter for resistance while the truck is OFF. If there's some discrepancy with the readings between each cylinder, you'll then have to trace the wires.
     
  5. Michael Gain

    Michael Gain Full Access Member

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    Yes, sir. There is spark. I am starting to think that this weekend is going to be smoke testing and multimeter testing intensive--i now hear a hiss under idle. Suspecting the vacuum pump based on sound location, but have not had time for further review.

    I will say, that if I have to pull an injector, I might as well do an entire refresh:

    Valve covers, intake gaskets, supercharger coupler and oil while it's off, all six fuel injectors, etc. It will only be about 1500 in parts and a week of my life-- I'm sure my wife will sign off on it
     
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  6. Michael Gain

    Michael Gain Full Access Member

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    Update #12.5

    Towed to a better Indy outside of Nashville. My wife was tired of my tinkering.... They completed a compression test (all above 175) and spark / coils check out. Leak down test is running overnight. If that comes back clean, on to the fuel system... if not, we get to pull the passenger head.

    I'll update tomorrow
     
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  7. Michael Gain

    Michael Gain Full Access Member

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    Final update.

    Leak down test came back clean. Injector 3 & 5 replaced, codes are cleared, and she runs great (according to the indy).

    I'm picking it back up this weekend and highly optimistic!

    Evidently, injectors can be replaced without removing the supercharger. So, I'll replace the other 4 in the next few weeks so everything is balanced.
     
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  8. Michael Gain

    Michael Gain Full Access Member

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    Replaced the passenger side fuel injectors and ignition coils.

    Not too bad. Did not have to remove the A.C. lines, but did have to disassemble the driver battery box.

    #2 injector needed over 100 hits and some leveraging with a pry bar. #4 and #6 came out with 2-3 pulls.

    Everything is back together minus the pieces that need to be off to pull the supercharger. That process will happen over the next couple of days

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