WOT open loop bog | Ford Escort Owners Association (FEOA)

WOT open loop bog

Discussion in '2nd Gen 1991-1996 1.9L SOHC' started by Mrbwin, Dec 6, 2019.

  1. Mrbwin

    Mrbwin FEOA Member

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    Just got a 93 1.9l manual trans car. It falls flat on its face at wot. For example, if i floor it in 1sh, it will rev to about 17mph, or 3k rpm by my calculations & scan tool. Then, it will feel like i have the brakes on. Engine monitor shows it's in open loop, fuel trims max out at 150%, and it will slow down (still flooring it) to about 10 or 12 mph, come back into closed loop mode, and take off again. At 75% throttle, it will rev past that, and loose steam at about 22 mph, 1st gear. Same deal in all gears, adjust road speed accordingly. Any experience with this out there? Idles and revs smooth below that rpm.

    Thanks in advance.
  2. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    Clogged fuel filter?
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  3. Mrbwin

    Mrbwin FEOA Member

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    Think so? It's worth a shot. I never have any codes, injector duty cycle doesn't seem high during regular running. I think i have a filter. I'll swap it.
  4. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    It sure sounds like it's starved for fuel, a plugged filter is probably the number one cause of fuel restriction.
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  5. JamesGarfield

    JamesGarfield FEOA Donator

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    Mrbwin,

    Any updates on your wot-open-loop-bog problem?

    I was gonna suggest to clean or replace the MAF sensor in the air intake. At the high airflow volumes of WOT, the element wires in a dirty or weak MAF sensor might not be up to the task.

    As Joey indicated, the fuel filter could be partially clogged. Getting to the filter is easy. I think replacing that filter should part of your annual maintenance schedule. I like the clear or translucent plastic ones, as they can provide a visual indication of cleanliness.

    Also possible could be a weak fuel pump inside the tank, if it can't provide enuf fuel flow during WOT.

    Do post back in what you find.
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  6. denisond3

    denisond3 Moderator Staff Member

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    I would suspect the pick-up 'sock' inside the tank before I would suspect the pump itself.
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  7. Mrbwin

    Mrbwin FEOA Member

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    Haven't dug into it yet. I'll start with the filter, because i have one. Is the pump accessible without dropping the tank on these?
    Should have time this week to look at it.
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  8. denisond3

    denisond3 Moderator Staff Member

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    For the 2nd gen Escorts (91-96) you can take up the rear seat bottom, and unscrew the hatch cover - and be looking at the unit having the pump and fuel level sending unit in it. Depending on how rusty your car is you can work the lock ring around, and be able to pull the pump unit up and out. You need to undo the plugs, for fuel supply, fuel return, and the electricals. And you need to soak the lock-ring with penetrating oil. I had one Escort where the lock ring tabs were so rusty that I had to put in a new fuel tank. The tanks are plastic, so wont ever rust out via the bottom. Its only the lock ring tabs that get so rusty they kind of disappear. Generally you can carefully tap on the lock ring, to little by little drive it around so it comes free of the 'ears'. You can easily buy new lock rings and a new rubber sealing ring.
    To get the rear seat bottom off, there are two clips you have to push back, either with a screwdriver or a strong thumb. They are both about 13" inward from the door panels. Then the seat will be stuck to the metal of the car, from years of being pressed onto it.
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  9. zzyzzx

    zzyzzx FEOA Member

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    Then the seat will be stuck to the metal of the car, from years of being pressed onto it.

    I assume that next time that I remove the seat, it will be much easier to remove.
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  10. Mrbwin

    Mrbwin FEOA Member

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    Well, swapped out the fuel filter. No change. Cut open the old one just for fun and it was spanky clean. I guess next is check the fuel pump sock? I have previously cleaned the MAF sensor, hoping that would help. Nope.
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  11. denisond3

    denisond3 Moderator Staff Member

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    I had a bad misfire whenever I opened the throttle from low speed. That turned out to be a bad spark plug cap.
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  12. Intuit

    Intuit FEOA Member

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    Sounds like it doesn't have enough power to get going. What are the engine load calculations? Pull off the harmonic balancer a.k.a. crank damper and check the slot for widening, where the woodruff key slots into on its inner circumference. (note: it *must* be pulled off to check)
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  13. denisond3

    denisond3 Moderator Staff Member

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    And can recheck for a slipped timing belt when the crankshaft pulley/damper is off.
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  14. Mrbwin

    Mrbwin FEOA Member

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    Hey, thank you for chiming in. I did have a small misfire/stumble at idle, but replaced plugs,wires and coil pack. Never misfired at WOT low speed though.
  15. Pizzaman5000

    Pizzaman5000 FEOA Donator

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    ^^^^^^^^^^^^^^+1
    Replaced the pulley on both escorts I have fixed up. They ran so much better. Literally .5mm of wear on the tip of the <90° corner will make a edis Ford run like CRAP!!!

    Worst I saw, my exhaust manifold was GLOWING at idle.

    Not saying it's your problem, but it's actually a critical tune up point.
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  16. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    How do the tips of the "teeth" wear?
  17. Pizzaman5000

    Pizzaman5000 FEOA Donator

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    The keyway on the crank dampener. ANY play, and the spark timing goes nuts. It's more than just a couple degrees, it's multiplied by 4 or 8. I forget how that works.

    The keyway isn't perpendicular to the crank, it's "off" by a few degrees. The side with less than a 90° angle gets worn on the acute corner. It is almost like a beveled edge when damaged. Once the sharp corner gets a flat spot, it's trash.

    I'm so paranoid about it, I install the crank pulley.. fire it up. Shutdown, retorque. Run a few miles, and IMPACT it on.
    Even after all of that, I still give it a few ugga duggas a couple hundred miles later.

    Last time I had it happen, 300 miles after torquing once, and impacting once, it started bucking and hesitating on the highway.

    After 3 shops declined to touch it, I found a shop full of 90's Ford's. They did it for free on the spot.
    Don't know if they were aware of my concern, or just liked the old Ford. Ran like a champ afterwards, and went 15k miles trouble free afterwards.

    I doubt this is O.P.'s issue though.
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  18. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    Okay, I see now. I had a Mazda B2200 I picked up for scrap price due to the same problem. I think in that case the timing belt was changed and the pulley bolt not tightened up properly. The pulley was loose and would shift around advancing and retarding the camshaft and distributor timing randomly causing rather erratic running.
    The keyway groove was badly wallowed out.
  19. Intuit

    Intuit FEOA Member

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  20. Mrbwin

    Mrbwin FEOA Member

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