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is this a fuel issue? or an air issue? how should i diagnose

Discussion in 'Engine/Tuning' started by P49Y-CY, Aug 5, 2019.

  1. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    I finally got a chance to mess with this a little bit...

    I am pretty sure that it is not either the air filter or the fuel filter - the k&n air filter looks very clean (no oil residue inside the intake tract), and the fuel filter was done only about 30k ago. so therefore i doubt if the maf has been contaminated in any way.

    originally thought it was running super rich because the insides of the tailpipes looked extra dark, but when i pulled the plugs they all looked great (no fouling) so i doubt that's the case.

    the car runs great and a normal startup idle when i start it up. it runs if i pull the maf harness and plug it back in (with a little hiccup in idle each time i do so). but it runs and settles into a nice idle.

    that is what is frustrating about this - it seems to be an intermittent problem. it runs good now in my driveway, but who knows if the same thing will happen out on the highway. (it will lol)

    one thing that i did notice however, when i pulled off the inlet tube, was a rather large amount of engine oil inside the throttle body. even dripping out of one side when i open it. sort of like the condition that people who use oil separators are trying to avoid. so there is a lot of oil residue, but i sort of expect that from a car with 126 hard miles. i predict that the heat exchanger underneath the eaton is extremely dirty. the top of this engine has never been opened.

    so i think my next steps i think will be to remove the throttle body and elbow from eaton, and remove all vacuum lines to make sure they are ok.


    sorry that i missed your original comment, and thank you very much for your feedback. it was dying even when i was trying to give it gas. i will check out the best way to check the fuel pressure drivers module. i do have a spare iac that i can put on there to check, but right now it seems running good at idle.

    turns out the handheld i have for this car is an old sct x2, so i won't have the capability to datalog that way.
     
  2. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    oh and the car starts and idles fine with just the open throttle body (entire intake tube, maf, and iat disconnected)

    shouldn't it give me a code when i do that? thx
     
  3. slo984now

    slo984now AKA 01yellerCobra Established Member

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    Yeah, you should get some kind of code for the MAF being disconnected. At least I remember getting one when I drove with mine disconnected. Maybe it's a hard set code that you need to scan for?
     
  4. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    yeah and so far i just have it idling in my driveway for a few minutes at a time, so maybe the code would come on if it ran for longer or if i tried to drive it that way. thanks for the feedback bob

    also, when running like this (open throttle body with no intake tube) i notice that there is no suction at that small vacuum line that attaches to the left hand side of the stock intake tube...

    shouldn't that line have vacuum at that location when the car is running? im thinking maybe that line might be clogged with oil or something

    edit: actually, scratch that - it probably pulls vacuum from the throttle body side of the line - so nevermind, sorry
     
    Last edited: Aug 16, 2019
  5. DSG2003Mach1

    DSG2003Mach1 Well-Known Member Premium Member Established Member

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    The xcal 2 can log younjust need a cable and a laptop to do so. Honestly I’d probably just buy the Bluetooth obd2 reader though
     
  6. hotcobra03

    hotcobra03 Well-Known Member Established Member

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  7. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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  8. bigmoose

    bigmoose Well-Known Member Established Member

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    When I had issues with my FPDM I had similar symptoms. It would sometimes go wonky and the car would struggle to run and drive. If I let it sit for 15 minutes it would be fine again.

    They are an easy cheap part to replace to see if it helps.

    A new FPDM fixed my issues. Not an issue anymore since I went return.
     
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  9. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    I have researched more about this and I am 89% sure it is the fuel injectors. It looks like the fuel rail is pretty easy to get to on these, so I am going to swap out from my coupe to make sure that's the problem, instead of just buying new ones. But from what I understand the OEM injectors are discontinued. I will post up the results. Thank you folks for all your feedback!
     
  10. hotcobra03

    hotcobra03 Well-Known Member Established Member

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    How about another mass air flow.

    On mine if I in plug car stalls

    I think if it stays running is a test for a bad sensor
     
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  11. slo984now

    slo984now AKA 01yellerCobra Established Member

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    If you want to keep one car running I just pulled my stock injectors and I have a spare FPDM as well. I know my injectors are good as I drove the car right before parking it for the blower swap. I can send them to you if you want.
     
  12. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    hey that is very nice of you, bob! thank you

    i will send you a pm. also if you still don't have that metco lower pulley hex tool i have one i can lend to you :cheers:
     
  13. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    Well apparently my 89% was too optimistic lol. It runs fine for a while, but after it gets really hot (running for say an hour or so and starting up fine during that period) it shuts down and then won't start back up until it cools way back down.

    It must be something that is affected by heat (but not direct engine heat).
     
  14. slo984now

    slo984now AKA 01yellerCobra Established Member

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    I'm still leaning towards a pump dying. Need to get some datalogging going on. Since it sounds consistent it should be easy to spot.
     
  15. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    i like that idea bob - that will be the next direction i go, thanks
     
  16. DSG2003Mach1

    DSG2003Mach1 Well-Known Member Premium Member Established Member

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    Did you try swapping the FPDM? They will do that too when they get hot as they get old/weak.
     
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  17. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    still been working on this here and there. still don't have it solved, but definitely getting closer... even if only through the process of elimination! lol

    at this point i have swapped out just about every part that i could get to without dropping the fuel tank: maf sensor, iat sensor, air intake filter, throttle body/elbow, injectors, fuel rail pressure sensor, fuel pump relay module, pcv valve, egr valve, etc.

    neither my xcal2 or xcal3 seem to be cooperating with either livelink program, so i still havn't been able to do any datalogging. maybe they are just out of date. but to update the xcal3 device from the sct website software i would need to load my stock tune on my coupe and i don't really feel like doing that.

    so at this point, i am going to try swapping out the fuel pumps. i checked the prices and they are pretty expensive, so i don't want to buy them in case it is still not the issue. but unfortunately i will need to drop both gas tanks to do that.

    i have never dropped the gas tank before, but i will say that overall this has been a good learning experience for me so far!
     
  18. slo984now

    slo984now AKA 01yellerCobra Established Member

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    I think the newest version of Livelink needs an X4. Or so that's what I've seen. I haven't updated mine in awhile as I switch between the Xcal2 and X3. I wonder if I could send you a copy of the old version I use with my Xcal2?
     
  19. P49Y-CY

    P49Y-CY selfie deaths ftw Established Member

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    well i appreciate that bob. i do have the "first" generation livelink installed on my computer, which is what was used with the xcal2, but it just gives several different error messages.

    i think that the xcal3 is still supported by the current livelink (second generation) on the sct website, but the device has to be up to date. it says the following when i try to use livelink II with my xcal3:

    "Device firmware 1.2.134.0 is not supported by Livelink. Minimum X3+ device firmware supported is Ford *.2.153.0. Please upgrade device and try again".

    And like i say, it does appear to be willing to update/upgrade my X3, but it said that i'd need to install the stock tune on my car before doing so.

    I am also going to research the bluetooth obd2 reader that DSG2003Mach1 mentioned in post #25.
     
  20. slo984now

    slo984now AKA 01yellerCobra Established Member

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    You and I live just far enough to be annoying. I have 2 Xcal2's, 3 X3's, and an X4 at my disposal. I still use the Xcal2 with the old school Livelink 4.2 for my WOT tuning. I use the X3 for part throttle. I haven't bothered to switch the cable from serial to firewire.
     
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