Need help with a 97 F150

Discussion in 'All Non-S197 Media' started by Flusher, Apr 19, 2021.

  1. Flusher

    Flusher Member

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    Apparently I'm now "the Ford guy" at work, just because, combined, we own four Mustangs.

    My boss acquired a '97 F150 with a 4.6L 2V engine that might have a couple dead cylinders. He took it to his friend at a Chevy dealership, who replaced the coils and told him, "It needs a new engine." The original engine was running so rough that it felt like it had a broken con rod.

    We didn't dig into the old engine to diagnose it, however we did uncover some issues, such as the PCV hose from the DS VC to TB not being connected.

    The truck and a replacement engine, from a salvage yard (with a 3 year warranty), show up at my shop.

    My son and I swapped the engine and performed the following:
    New plugs
    New gaskets - oil pan, valve covers, and intake
    Oil/filter
    Water pump
    All new hoses
    New fuel filter
    New air filter.

    The condition of the new engine looks pretty good, based on inspecting the cams, spark plugs, and pulling the oil pan.

    After firing the new engine, it idles rough and acts like it wants to stall. It doesn't run anywhere near as bad as the original.

    I replaced the MAF sensor and IAC valve. The running fuel pressure is 34 PSI. The running fuel pressure increases about 5 PSI when I pull the vacuum line off the fuel pressure regulator, so I did not replace the regulator or pump. I did not replace the O2 sensors or cats.

    Any suggestions are greatly appreciated. I don't want to just keep throwing money and parts at it.

    Thanks in advance.
     
  2. 86GT351

    86GT351 forum member

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    Codes? Have you scanned it for Trouble Codes? Looked at any data?
     
  3. Flusher

    Flusher Member

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    My son has a basic scanner, said that it's in "learn mode" with no codes.

    I have a friend with a better scanner coming tonight, he will be able to tell me everything. He did say that everything I did should have popped a bunch of codes.

    Currently, I'm only capable of scanning the 1D10T code when the CEL illuminates.

    Forgot to mention that I did check for vacuum leaks.

    Thank you

    P.S. I assumed that if there was a code, there would be a CEL.
     
  4. 86GT351

    86GT351 forum member

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    Not always. There are many times that there are codes stored but the light did not turn on. That is why a good scanner with Data is so vital in diagnosis these days.
     
  5. Flusher

    Flusher Member

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    Thank you, I will look into just such a tool as soon as budget permits. Bringing my CNC online has to be priority.

    Unfortunately, I am doing this job in duress, this was supposed to be my son's job. I'm just trying to help the two guys out. No good deed goes unpunished.

    Fortunately, I have a kind-hearted friend, who just happened to be up at midnight, with just such a tool, AND is willing to come by tonight... Just 11 more hours!

    Thanks again
     
  6. Flusher

    Flusher Member

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    How far back does that data logging feature go? I don't believe the Mopar stuff has anywhere near that level of sophistication.
     
  7. Juice

    Juice forum member

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    You cannot beat Forscan for diagnostics and live data view. Free program, just need a good ELM327 adapter. I prefer usb cable one, but there are BT & WIFI ones too. No license needed for Forscan for diags, only for programming/configuration.
    Ps: fuel pressure seems a tad low to me.
     
  8. Flusher

    Flusher Member

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    Thank you. For some reason I had the number 42 PSI in my head. Not sure where I got that, maybe it was supposed to be 44 PSI (3 bar). I was going off of these numbers: https://www.f150online.com/forums/v8-engines/489454-fuel-pressure-4-6-fuel-rail.html

    I was definitely wanting to ask if there was a tuner that would double as a scanner. I can't dedicate any time to that right now, but I'm hoping there is still a future where I could dive into that.
     
  9. Flusher

    Flusher Member

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    Codes were:

    P0500 - Vehicle Speed Sensor Malfunction

    P1000 - OBDII Monitor Testing Not Complete

    B1352 - Ignition key-in – circuit failure
     
    Last edited: Apr 20, 2021
  10. Flusher

    Flusher Member

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    Going through everything, from every angle, I wanted to see if all plugs were getting spark, I put a timing light on all eight plug wires. There is not a steady strobe of spark and #7 is mostly not getting spark at all. I tried two different coils and two different plug wires with the same results. Swapping the new spark plug for one of the old plugs got me from no spark at all to intermittent occasional spark. Connecting the #7 plug wire to a loose spark plug and completing the circuit to ground, produces steady strong spark.

    I noticed that, while having the #7 plug out multiple times, it doesn't appear wet with fuel at all. I also don't see any sign of fuel inside the #7 cylinder.
     
  11. Flusher

    Flusher Member

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    Decided to put my compression tester in #7. This is a first for me, i have never experienced zero PSI in a cylinder before. #1 was at 160 PSI.

    I'm done for the night.
     
  12. 86GT351

    86GT351 forum member

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    Zero Compression equals Zero Heartbeat
     
  13. Juice

    Juice forum member

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    Got a 30 day warranty on that used engine?
     
  14. Flusher

    Flusher Member

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    Yeah, its warranteed, but I have to eat all this job.
     
  15. Flusher

    Flusher Member

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    Thank you all, I really appreciate the support.
     
  16. Juice

    Juice forum member

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    Yup, that sux. Id ask why you didnt check compression on the replacement engine, but, I did't check my coyote becore installing kt! So I wont ask. lol I know someone who detailed and installed a used engine, to find its locked/siezed solid.....
     
  17. Flusher

    Flusher Member

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    I made that decision based on the following logic:
    1) First thing we did was change spark plugs. The old plugs didn't indicate any issues.
    2) We had the oil pan and valve covers off to change the gaskets. Everything looked pristine inside.
    3) The starter bolts to the bellhousing. We didn't pull the transmission with the engine. We didn't really have a good way to crank the engine over to compression test.
    It was my decision and I own it.

    I'm going to do a leakdown test tonight to see if it is an easy fix. Also trying to source another engine.
     
  18. Juice

    Juice forum member

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    Any time I come across zero compression, it was a cylinder head/valve issue. If it really looked clean inside, there is hope it can be a simple fix. Got my fingers crossed for ya!
     
  19. Flusher

    Flusher Member

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    Thank you
     
  20. Flusher

    Flusher Member

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    Why didn't you test yours?


    Exactly, #7 exhaust valve was stuck wide open.

    Update:

    Place we got the engine from is going to warranty it, no problem.

    Went to get one yesterday. They ran it up to operating temp before pulling it out of the vehicle. Once it got some temp in it, it started knocking really bad.

    They are supposed to have another engine for us today.
     
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