Fuel injectors or damper?

Discussion in 'General Automotive Tech' started by escortwgn, Mar 26, 2022.

  1. escortwgn

    escortwgn Active Member

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    Finalizing my efi upgrade. Running, driving, and sorta idling at times. Long story short. Vacuum plugged in to fpr 32psi, unplugged 40psi. Vacuum plugged in engine is stumbling, unplugged smooth as a baby’s bottom. Off the donor car, Grand marquis, I reused the fuel damper. Installed new fuel pump. New 19lb fuel injectors. I’m thinking perhaps the damper is perhaps restricting flow a bit, or I got crap injectors.

    85 LTD Country Squire with 89 mustang A9L computer
     
  2. Silvertwinkiehobo

    Silvertwinkiehobo "Nothing is foolproof as fools are ingenious."

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    The pressure change is at the low end of correct, and vacuum-regulated pressure is within spec. Have you run codes, see if it's set something that is affected by the fuel pressure reduction? Also, did you have a vacuum gauge on the engine source vacuum, to ensure the vacuum is steady, regardless of vacuum reading? Aaaand, did you clean the IAC, verify it's working? One other thing, if the MAF is unplugged and the engine smooths out, it's the MAF.
     
  3. escortwgn

    escortwgn Active Member

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    I have not done a vacuum check. Only code is 34, egr not opening. IAC is as clean as I can get it, and it’s working good. Unplugging maf, the engine doesn’t like that
     
  4. Silvertwinkiehobo

    Silvertwinkiehobo "Nothing is foolproof as fools are ingenious."

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    Trace the EGR source vacuum, from the black EVR back to the intake, to verify you don't have a vacuum leak. Also do so for the rest of the source vacuum lines. And, unplugging the MAF shows it's not a MAF problem. Just a quick check, since you married the MAF to an otherwise SD EFI system.
     
  5. escortwgn

    escortwgn Active Member

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    I have the wrong solenoid for the egr. Just using a universal vacuum solenoid.

    Vacuum is at 18
     
  6. Silvertwinkiehobo

    Silvertwinkiehobo "Nothing is foolproof as fools are ingenious."

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    The vacuum is at the bottom of the spec (18-22"), so you could have a minor vacuum leak. When you unplug the FPR, do you cover the vacuum line?
     
  7. escortwgn

    escortwgn Active Member

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  8. escortwgn

    escortwgn Active Member

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    My idle was a little low. I’m running 19.5-20 inches, fpr plugged in 33psi, and 40/42 unplugged. Tps is .97. Base timing at 10. Idle 680. Seems to be doing fine today………
     
  9. Silvertwinkiehobo

    Silvertwinkiehobo "Nothing is foolproof as fools are ingenious."

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    One thing that I just remembered, the computer needs key cycles and hot/cold/hot cycles to learn idle and fuel mapping. You may have been a 'victim' of that. And BTW, EVRs are common as gravel. As long as the connector design is correct, you can pop one on from another car, get rid of the one you are using, because I'm sure it isn't working. The EVR is pulse-width-modulation controlled, and if the one you're using now is not, the PWM signal won't have enough oomph to actuate it.
    Anyway, your numbers all look good ATM, so of course, keep track of them, and we all look forward to a long-distance drive of your wagon.
     
  10. escortwgn

    escortwgn Active Member

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    The gremlin is showing up, but looks like it’s the IAC. In gear and with ac on sometimes it reacts to load, and other times doesn’t. Vac is holding at 20. Engine not jumping around. Idle no load isn’t hunting like is was yesterday. Done a small drive. Turned off, restarted engine and no issues other than occasionally whilst under load. In gear 500-550. In gear w/ ac 470-500. Just ac 530-550.
     
  11. escortwgn

    escortwgn Active Member

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    The evr will be purchased this week. Read that last night about them.
     
  12. Silvertwinkiehobo

    Silvertwinkiehobo "Nothing is foolproof as fools are ingenious."

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  13. escortwgn

    escortwgn Active Member

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    how long should it take? I finally have it on the road, trans shifting like a dream. I set idle, test in gear, with air on, drive it a bit. Once I turn it off and on….it forgets that it’s a car. Idle returns to an extreme low, tapping throttle doesn’t help. Holding throttle for a bit gets it to remember to idle higher. This has been going on for about a week. Replaced the IAC today, idle did smooth out a lot, but the low idle is still there. I’m a bit confused. Am I still in the learning loop? Also I have unplugged the battery over night to drain the KAM so to do erase previous idle
     
  14. Silvertwinkiehobo

    Silvertwinkiehobo "Nothing is foolproof as fools are ingenious."

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    I'm not exactly sure, but I *heard* that idle and fuel mapping takes around fifty full key cycles, meaning you drive it from cold to hot, then let it sit overnight to go back to ambient temp.
     
  15. escortwgn

    escortwgn Active Member

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    Ok, well then I’ll def be taking out on every little trip out of the house then. Just weird how once warm idle struggles at 450 or less then finally jumps up to norm after I force it to move. Will post an update if/when there’s an improvement
     

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