Help needed with slow idle / stalling. | Ford Escort Owners Association (FEOA)

Help needed with slow idle / stalling.

Discussion in '2nd Gen 1991-1996 1.9L SOHC' started by denisond3, Aug 16, 2019.

  1. denisond3

    denisond3 Moderator Staff Member

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    I need help with my 94LX wagon. It developed an idle so slow and uneven that it stalls at almost every traffic light, if I dont give the gas pedal little nudges. This started about 9 months ago, down in TX. It seems to run fine when driving along, so we drove it up the 2000 miles to VA in May, where it has been mostly sitting because its hard to drive in traffic. I have checked the obvious vacuum lines. I dont think its a fuel pump problem, since it runs well at 70 and up. I dont have a good gauge for measuring the fuel pressure, since the gauge reads to 300 psi; kind of hard to see pressures in the 18-25 psi range. As soon as I nudge the throttle valve to speed the engine up - it lapses into perfect running until the idle drops back all the way down. I replaced the Idle Air Control Valve with a Chinese aftermarket one. It is a 5-speed.
    Is this the kind of issue I would have if the timing belt had jumped a tooth; i.e. a very slow idle? Any suggestions would be welcome. The timing belt has been on this car for about 50,000; most of them on interstates. The engine has about 160,000, but with a rebuilt head; original coil pack and EDIS-4. The cat converter was replaced about 12k miles ago - the old one broke at the bottom elbow.
    P.S. I have an identical 94LX wagon that lives in TX, and was running fine that last time we drove it.
  2. zzyzzx

    zzyzzx FEOA Member

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    Did you check for codes? I don't care if you aren't getting a dash light.

    Checking vacuum lines doesn't rule out vacuum leaks in devices connected to to these vacuum lines. For all I know, that vacuum solenoid is leaking (either externally, or straight through).

    In so far as checking the fuel pressure, there are loaner tools at auto parts stores if you to rule that out. My guess is that you will find fuel pressure to be fine.

    I know that you mentioned that the timing belt has 59K miles on it, but how old is it?

    When was the last time you cleaned the MAF sensor?

    How many miles are on the spark plugs? How many miles since they have been cleaned?

    Are you sure that it doesn't have EGR valve issues? The EGR valve could have a vacuum leak, or could be clogged. Even the small part of the intake manifold that juts out from the manifold to the valve itself can get clogged. Mine was partially clogged when I cleaned it out af days ago. I am assuming that this Escort has an EGR.

    I would also check the air intake flex hose. I do not recall anyone here mentioning this, but I have had one go bad on another car, and it was much newer than my Escort. The thing is that you really have to remove it to completely check it since it will most likely break someplace where you can't see, and it's the only way to check all the pleats. If it's letting in air, you are getting unmetered air, and your car might not run right.
  3. denisond3

    denisond3 Moderator Staff Member

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    Thanks for the ideas. The timing belt is about 5 years old. When I take off the rubber inlet air duct, the idling engine stops; but I didnt see any tears in it. Since I have two other Escorts in the yard, I can sawp the MAF to see if thats the cause; same with the coil pack and the EDIS. The spar plugs have about 20,000 miles on them. The last time I looked at them was before this began happening; so is time to reinspect.
    I havent checked for codes yet. The CEL is on, because I have disconnected the vacuum port to the EGR valve - which valve was replaced about 20,000 miles ago.
  4. zzyzzx

    zzyzzx FEOA Member

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    OK, so it can't be a vacuum leak at the EGR valve, since it's already disconnected with the line plugged.

    Check all the other vacuum using devices for a vacuum leak. Like that solenoid. I am not sure how to check for a vacuum leak inside the power brake booster, but the rest can be checked with a MityVac type device.

    Just out of curiosity, will your other Escorts stall if you take off the air intake tube?
  5. denisond3

    denisond3 Moderator Staff Member

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    One or two do, one or two dont. Mostly they seem to idle noticeably worse, but still struggle along for at least a while.
    And it could be a leak at the EGR valve, allowing exhaust gases to get pulled in - which at an idle might be enough to cause stalling. I will be sealing off the inlet from the EGR valve into the intake manifold. (After I check the timing belt marks.)

    With the brake booster line disconnected and capped shut at the connection atop the intake manifold, the idling/stalling was the same.
  6. Krankie

    Krankie FEOA Member

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    In my mind, that Chinese IAC is suspect. Try swapping with a known good one from your other car? Also check if it is getting power with a noid light if need be, i.e. swapping it doesn't make a change
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  7. denisond3

    denisond3 Moderator Staff Member

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    Thanks for that idea.
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  8. Pizzaman5000

    Pizzaman5000 FEOA Donator

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    I have had weird symptoms with the vacuum line to the EGR valve unhooked and the dpfe pigtail still connected. The egr valve shouldnt open without the dpfe plugged in, but I believe the timing won't be affected the same if only the vacuum line is disconnected.

    It's the dpfe's that I dont trust.
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  9. zzyzzx

    zzyzzx FEOA Member

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    I was also assuming a cheap Chinese IAC, and wondering about it.
  10. denisond3

    denisond3 Moderator Staff Member

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    I made up a multi-page list of things that might cause my symptoms.
    For example, what if the Crankshaft Position Sensor is weak due to a cracked magnet inside. Perhaps at low rpm the pcm isnt getting a reliable signal of the engine spinning?
  11. zzyzzx

    zzyzzx FEOA Member

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    I have had that happen on a Dodge truck. The truck kept stalling until it finally wouldn't restart. Only then would it give out the appropriate code, which my $200 OBDII code reader wouldn't pick up, but if I turned the ignition key on and off 3 times quick enough, it would display the code on the odometer. Once replaced the truck ran great.

    I would think that you would just swap suspicious parts over from another Escort.
  12. denisond3

    denisond3 Moderator Staff Member

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    That is pretty much what I will be doing. But I need to swap them over one at a time, to know what fixed it. I realize that I may have a problem with more than one contributing issue.
  13. zzyzzx

    zzyzzx FEOA Member

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    Don't forget about the power steering and air conditioning switches (if applicable).
  14. Marvin

    Marvin FEOA Member

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    I am the third person to suspect the cheap IAC. Did you clean the throttle body and passages? Typically on a hot running engine with a clean and properly adjusted throttle body the car should be able to idle (very slow and poorly) with the IAC unplugged. Then plug the IAC in as it is running and it should respond immediately.

    Others mentioned EGR valve being stuck open. Sometimes the solenoid that controls it malfunctions and will not bleed off vacuum due to a dirty foam filter. Disconnect the vacuum hose to the egr valve to see if it changes. Tap the base of the EGR with a hammer in case it is stuck. Lastly apply vacuum to the valve and the engine should run worse/shut off. If you find the EGR vacuum solenoid is bad often you can pop off the round cap and clean the foam filter with soapy water.

    Disconnect the electrical connector to the MAF sensor. If it runs normal with it disconnected you may have a MAF issue, vacuum leak, or tube problem running to the MAF. Check your PCV valve to make sure it's not bad and sucking way too much air. It should rattle and not be stuck if you shake it.
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  15. zzyzzx

    zzyzzx FEOA Member

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    I am also suspicious of this. I tried to clean mine without taking it off, and made it worse.

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