Stumbling engine on cold start | Ford Escort Owners Association (FEOA)

Stumbling engine on cold start

Discussion in '3rd Gen 1997-2002 2.0L SOHC' started by Adamprince2, Dec 19, 2018.

  1. Adamprince2

    Adamprince2 FEOA Member

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    My engine has been stumbling only on cold starts. It feels like the engine is missing for about 3 to 5 seconds after startup until I rev the engine a few times makes it go away. It only happens on cold starts. If I dont rev the engine the problem lasts longer. One time the car would not start until after several minutes of cranking and resting even with holding the throttle.

    Weather: 20-43f
    Radiator pressure test: lost .75 psi at 12.5 psi over 31 minutes.

    Brand new timing belt, radiator, hoses, water pump, oxygen sensor. System was just flushed with irontite.

    24,500 miles on fuel filter.

    Tapped on idle air control while it was stumbling but it did not help.

    It runs fine after the initial stumble.

    Any ideas?
    Last edited: Dec 22, 2018
  2. rbailin

    rbailin FEOA Member

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    You might have a leaky fuel injector or a very small coolant leak, usually from the inner intake manifold gasket.

    Try leaving your radiator cap in the loose position for a couple of days (turn the cap counterclockwise without pressing down until you hit the stop). You won't lose much coolant into the overflow bottle unless weather warms up significantly and you're stuck in extended bumper-to-bumper traffic. You'll be running with a zero pressure cooling system which shouldn't be a problem. (I've been doing it carefully for 3 years now.)

    If the problem goes away, you have your answer. The leak is usually into the #2 cylinder from the unused water jacket hole in the center of the intake gasket. If you had a head gasket leak, put the pressure tester on when the engine is cold and then start the engine. If the pressure rises quickly, you have an exhaust leak thru the head gasket that may close as the engine heats up. The pressure should only rise slowly from the gradual increase in coolant temperature.

    If it persists, try cranking the engine with the gas pedal fully depressed for 15-30 seconds to clear the excess gas from the affected cylinder. After doing this, the engine should start up normally with your foot off the gas pedal as usual. Normally, a leaky fuel injector is more of a problem in warm weather.
    Last edited: Dec 22, 2018
  3. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    One suggestion I will make is to not crank the engine for extended periods. Crank for a few seconds, let it rest a couple of seconds and try again.
    That's how all of the older fuel injected cars in my family's fleet start best.

    Normally when starting FI cars, the accelerator should not be touched when starting.

    Ultimately I wouldn't worry about a car that runs rough for 3 - 5 seconds after starting, just let it warm up for ten seconds.
  4. Adamprince2

    Adamprince2 FEOA Member

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    Thank you for the input. I reran the coolant pressure test at 16 psi after letting the car sit for 18 hours. Similar results about .5 psi lost in 10 minutes, .75psi in 30 minutes.

    Released the pressure and started the engine. No measurable increase in the gauge.

    Next up is a fuel pressure test and run the cap loose. Maybe borescope number 2. Check the vacuum.


    This all started immediately after doing the cooling system and timing belt service. Perhaps the flush freed something it shouldnt have.
  5. pextor

    pextor Moderator Staff Member

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    spark plugs and wires?
  6. Intuit

    Intuit FEOA Member

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  7. Adamprince2

    Adamprince2 FEOA Member

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    Fuel pressure test Engine ON: at 32 psi (Spec. 35-45 psi), the pressure regulator was confirmed bad by squeezing the return hose. Leak down test was less than a psi over 10 minutes. I ordered a new USA made regulator for about 1/3rd the cost of the parts store: https://www.amazon.com/Injection-Pressure-Regulator-Mercury-Lincoln/dp/B07KRLDFWQ/ref=sr_1_1?ie=UTF8&qid=1545861439&sr=8-1&keywords=New Fuel Injection Pressure Regulator for Ford Mercury Lincoln

    Wires and plugs have about 34,000 miles on them. I used the superseded Ford recommended plugs.

    Continuing to run the radiator cap loose. Last few days the engine has been starting without the large stumble/shaking, but it's been warmer. My gas milage has been fairly poor. I always get in 26-28 mpg with lots of urban/highway. When I had a manual escort I got 33-36 mpg.

    Intuit, I recall confirming the two valve timing marks by turning over the engine twice before tightening the harmonic balancer with a corded Dewalt electric impact. The rubber on the balancer looked old though. So the harmonic balancer could be effecting the reading on the crank angle sensor.
    Last edited: Dec 26, 2018
  8. Intuit

    Intuit FEOA Member

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    Fuel pressure readings have to be very low to be impactful. It'll run fine on 32.
    Adamprince2 likes this.
  9. DC Ultra

    DC Ultra FEOA Donator

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    Look at the accessory belt? Just thinking.
  10. Adamprince2

    Adamprince2 FEOA Member

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    Ended up being the spark plugs had a deposit on one of them and the gaps had opened/wore. I even used a camera to check for fluid in each cylinder after sitting overnight, nothing. I cleaned the plugs and gapped them. I have not had any further trouble with a stumbling engine for weeks on cold start up.
    rbailin likes this.
  11. Adamprince2

    Adamprince2 FEOA Member

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    The small amount of leak down on the radiator pressure test was the thermostat housing and the heater core. Both have been fixed.
    rbailin likes this.
  12. Intuit

    Intuit FEOA Member

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    Interesting. Specifically for 2nd-Gen 'scorts, the first symptoms that there's an ignition system issue, presents itself when the engine is placed under load... or revved to high RPM.

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