95 1.9 lx runs good cold, warms up then runs bad. | Ford Escort Owners Association (FEOA)
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95 1.9 lx runs good cold, warms up then runs bad.

Discussion in '2nd Gen 1991-1996 1.9L SOHC' started by Schleprok, Nov 12, 2020.

  1. Schleprok

    Schleprok FEOA Member

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    Hello all, long time lurker looking for help. My 95 escort runs fine until it get up to temp (5 min) then starts running terrible, acts like the ignition or fuel is cutting on and off. Tha first time it happened, I left the house going to a dr appt. about 60 mi away. I got about 4 mi out when it stared missing bad. I turned around and went home to get the my truck and get to the dr office. It made it back home only stalled out once and started back up immediately. As I was on my way home, I tried wiggling the ignition switch because it seemed like it was losing power. And it seemed like it straightened out for a minute, so I was thinking maybe the ignition switch was going out. I replaced that but it still does the same thing, runs great for the first few minutes, then starts running like crap again. I did some research on here and other sites and found a post that sounded like what I was experiencing, bad fuel pump relay. So I replaced that as well, still no difference. A little background first, timing belt about 80k ago, new wires and plugs ( no not motorcraft) 10k and coil about 3k. Just replaced the clutch slave and master cylinders 200 mi ago. Any ideas guys? Thanks in advance, and love the site, it's helped me out many times over the years. And yes I searched the 2nd gen section for the last 500 posts, my eyes hurt from reading, help a brother out?
  2. marclar

    marclar Administrator Staff Member

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    very good chance it is a coolant temp sensor. when they fail the pcm thinks its -88* out and dumps massive extra fuel into the engine.
    zzyzzx likes this.
  3. Schleprok

    Schleprok FEOA Member

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    Possibly, I thought there were two temp sending units. One for the fans and the other sends a signal to the pcm? Last year my fan stoped coming on and I assumed it was the relay, if I remember correctly, so I unplugged the relay under the air filter box and just ran a manual switch to the fan. There were two relays, one for high speed and the other for low, is that right?
  4. Schleprok

    Schleprok FEOA Member

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    Possibly, I thought there were two temp sending units. One for the fans and the other sends a signal to the pcm? Last year my fan stoped coming on and I assumed it was the relay, if I remember correctly, so I unplugged the relay under the air filter box and just ran a manual switch to the fan. There were two relays, one for high speed and the o
  5. denisond3

    denisond3 Moderator Staff Member

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    There are two temp sending units, but one only feeds to the temp gauge. The other one feeds to the pcm, and the pcm is supposed to turn the fan on (low or high) as needed. If your a.c. system is still working, the fan will come on the high setting anytime you have the a.c. turned on. With the engine idling, pulling the connector off of the engine temp sensor should also make the fan run; but its not a good idea to drive it this way all the time.

    Another thing to think about though not of great help: When the engine is cold, the car runs on an 'open loop', using settings taken from a chip in the PCM. Once the engine is warmed up (or the temp sensor tells the computer so), it switches to a "closed loop" method. Here the fuel metering is controlled by the PCM, based on things like the feedback from the oxygen sensor, and the mass air flow sensor, and perhaps other factors - like the throttle position sensor or the EDIS (the igniter) which runs the signal to the coil pack.

    I had an infrequent 'stutter' when accelerating on one of my Escorts, which turned out to be a bad connection in the end of the spark plug wire. But that one was independent of the engine being warm or cold.

    If you can measure the fuel pressure in the fuel rail it might help eliminate some such problem as a clogging fuel filter.

    I have installed a manual switch to the fan, as an over-ride on one of my Escorts. This is used when we are sitting in motionless traffic on the bridge coming back into the states from Mexico. Those darn lines can easily be more than an hour long.
  6. Schleprok

    Schleprok FEOA Member

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    Thanks for the replies guy, yea, I remember about 1 unit feeding the gauge only now. So the fact that it runs normal when it's cold (open loop), then running bad after it warms up indicates the temp unit that feeds the pcm is working? My ac suddenly stopped working about 2 years ago, the compressor would just cycle on and off, so I gat a can of freon from wallyworld to give it a charge, but when I hooked the can up, the gauge on the xan was in the red indicating it didn't need any. I just read yesterday about the two relays on the firewall, maybe I'll get lucky with tapping on them to see if it blows cold again. I believe I've tried to get the fan to come on with the ac on, (not working) but it didn't turn on the fan. So when it goes into closed loop, and starts running crappy, would that indicate a bad sending unit (tps, o2, maf, or edis) ? When I replaced the coil a while back, I think I put a cheap one on it. It's possible that it's failing when it warms up, or would that more likely be the edis causing it to fail? Another thing I just thought of that's happening now is when I start the eng cold, it takes longer to start, it usually starts within 3 seconds, but now it takes longer. After about 5 seconds on the starter, I let off the key switch and try again, some times 2 or 3 times. But after it's warmed up, it starts as soon as you hit the key. May be toataly unrelated? Thanks again guys,
  7. zzyzzx

    zzyzzx FEOA Member

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    Check the ground node on the battery and the wiring to the coolant temperature sensor.
  8. Schleprok

    Schleprok FEOA Member

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    Funny you should mention that ground node, it has been melted for quite some time, so I eliminated it when this problem started think it was making an intermittent connection. But it didn't change anything. The wires to both sending units look good and are tight. Didn't denisind3 mention temporarily disconnecting that to see if the cooling fan comes on? But thanks for the input. Eliminating that nodewill not cause other issues, will it?
  9. denisond3

    denisond3 Moderator Staff Member

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    If the ground node you eliminted was the one at the negative terminal of the battery it wont affect anything, except in a good way. That rectangular connector was just a ground point. I have eliminated them on 3 or 4 of my Escorts, by just stripping the insulation back on the wires I cut off of the connector, and soldering them together with another wire - which I grounded to the bolt on the firewall behind the battery, where the negative battery cable is connected.

    If your a.c. system indicated it was fully charged when you went to add freon, but the system was cooling, I think either your compressor has a bad valve in it, or your receiver/dryer is gummed up. Neither problem can be fixed easily; since a rebuilt compressor is usually installed along with a new driver, and requires total emptying of the system, and being flushed and had a vacuum pulled on it, etc.

    And I dont have any better guidance on the problem of running badly when warm. Sorry.
  10. Schleprok

    Schleprok FEOA Member

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    Yea, the ground node was the one I eliminated, just cut whe wires and put a ring terminal on them and attached then to the ground terminal on the battery.but I may go back and remove and clean the ground connection at the body and move them there also, sounds like a better idea to put them there than on the battery, less chance of them coming loose. Would temporarily disconnecting the wires at the temp sending unit for the pcm and keep it from going into closed loop? If so, then if it keeps running correctly after warm up, I guess I'd just need to start replacing sensors, starting with the cheapest first, lol. I just hate to keep throwing money at it, no still fighting the same issue. Maybe I can find one in a jy and get the more expensive sensors there? I know it's a 25 y/o cheap car, but it gets 30 mpg and my truck gets 13mpg, so over the years that little cheap car has saved me lots of $ in gas, I've had it for 11 years and it's been quite reliable. I'm disabled and on limited income so every penny counts. Thanks again guys, stay safe.
    denisond3 likes this.
  11. zzyzzx

    zzyzzx FEOA Member

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    Sensors can and should be tested, and only replaced if they test bad. For the coolant temperature sensor, measure the ohms with the engine cold and warmed up, and post the results here. This would be the sensor with two wires on it.
    Last edited: Nov 15, 2020
  12. Schleprok

    Schleprok FEOA Member

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    Ok, thanks. I'll have to do that when I get back home on Tuesday.
  13. zzyzzx

    zzyzzx FEOA Member

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    It helps tremendously if you happen to have spare connectors with leads for all your sensors. I do. This is something that you should get at a JY at some point.

    For OBDII vehicles I just use the live data feature of an OBDII reader.
  14. denisond3

    denisond3 Moderator Staff Member

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    At rockauto(dot)com you can get new connectors for many of the old ones in your Escort. They arent cheap though, and a good supply of them adds up!

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