Check Engine Gremlins in 95 Taurus

[pscholte]

My 95 Ford Taurus is behaving oddly and I wanted to see if you guys had any advice. One morning last week my "Check Engine" light came on for about 3-4 minutes then went out. The next day in stop and go traffic it came on repeatedly but when the engine was stopped and restarted, no light. I took it to a mechanic and they apparently found no codes in the computer...I'm not even sure they ever got the light to come on even though they test drove it. Since then there has been little consistency. There are times when it never comes on (usually on a drive with few stoplights) and then others where it does (usually extended stop and go traffic)...but it always is off when I restart the vehicle and today after coming on repeatedly, I deliberately shutdown the engine and restarted it and it never came back on the rest of the trip EVEN with stop and go driving. I am baffled. The car seems to be running normally (gas mileage not affected, no hesitation under acceleration) except when coasting with the engine under little load, it seems to be hesitating or surging a little bit. Some people might not even notice it and it does not do it consistently, just now and then. I am baffled.

TNX for any help. (Since this started I have had the fuel filters replaced, the PCV valve replaced and the injectors flushed.)

PS The Elves are not kindly disposed toward the Gremlins.

 

[wavinwayne]

EGR flow insufficient?

Extremely dirty throttle body? - dont know if this could even cause a CEL???

bad spark plug or coil pack, bad plug/coil pack wire?

or 10,000 other electrical gremlins that are near impossible to track down?

Do you have a code reader that you can carry in the car with you? Wal-mart sells some cheap ones that will only show & erase codes; they are around $30. They also sell the more expensive ones. Good luck.

 

[Virtuoso]

Since it's a '95 you can check the codes with a paperclip..

http://www.shotimes.com/php-bin/mod...le=article&mode=thread&order=0&thold=0&sid=83

That should help you out a bit. As far as your surging goes, you may want to clean your idle-air valve.

 

[pscholte]

TNX guys...spark plugs and wires are new...I was wondering if there could be something beginning to fail, but even then why wouldn't the codes set and remain in memory?

 

[Gary Allan]

This happened in my daughter's 91 Taurus. It appeared temp related ..but never presented an operational problem. As though it needed to purge some air. It would not show on the gauge ..but would only present itself when you would think that a temp problem was occuring. It hasn't happened since the waterpump took a crap and I never stuck a scanner on it. Ford's pre-OBDII were by far the worst communicating systems out there. The GM systems of the same era were very informative on engine data. I used a Snapon scanner on my 86 Tempo ..it ran through a series of tests ..even blipped the gas on its own (gear driven idle solenoid) ..and after that, it just sat there with "waiting for fast codes" on the display ...and that's where it stayed.

quote:

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then why wouldn't the codes set and remain in memory?

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Some codes automatically reset themselves. For example, if you're in sub zero temps and the engine takes too long to reach op temp ..it will set the light that gives that code ..but it resets when the engine reaches op temp. I've had this happen in a pre-OBDII GM ..and a OBDII Jeep. In the OBDII the light stayed illuminated for the duration of the trip ..but reset itself upon the next startup and never came on again because the vehicle coincidentally reached the temp threshold in the appropriate amount of time (failing thermostat). It would be the same thing if you left your fuel cap off. You may not get a light between filling up and shutting it down, but you'll get one the next time you start it with it off after it completes its diagnostic on the evap system. When I had a gas cap fail, two codes were set. One for major evap leak and one for minor. The minor one is a pending code. It only lights the light if it remains "not reset" over a specified duration (xx starts, time, etc.)

Good luck!

[ April 24, 2005, 08:36 PM: Message edited by: Gary Allan ]

 

[deepsquat]

quote:

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Originally posted by pscholte:
TNX guys...spark plugs and wires are new...I was wondering if there could be something beginning to fail, but even then why wouldn't the codes set and remain in memory?

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well then how about something so simple as a plug wire has worked itself loose?

 

[punisher]

On some 88 up and all 91 up models FoMoCo EEC-IV systems had a DCL so you could see the data stream. Before then you had to hook up the 60 pin, and that was a PITA.

As far as a loose plug wire, it won't set a code on a pre OBDII vehicle, as a misfire sensor was not part of the bargain then. You certainly might get a lean code due to a constant misfire, but you would feel it long before a code would set. You can do a KOER cylinder balance test (SEFI only) if you do have a missfire though, I always thought that was a neat idea by Ford.

As said above, it is easy to check the codes yourself with nothing more than a jumper wire (connector on the firewall by the AC accumulator). It really is pointless to speculate on a cause until you have a code to work with. If it becomes a habit of a ck engine light without any codes present, time to think about a faulty processor or bad wiring to the light itself.

 

[Clement]

Check to make sure all the underhood connections are tight. Every once in a while I'll forget to plug a sensor back in when working on my wife's '94 Sable.

As it is a ford, though, My other recommendation would be to push it off a cliff.

I don't like Ford