Engine quits at 3000 RPM

1994 MERCURY CAPRI
120,000 MILES • 4 CYL • FWD • MANUAL
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PLAP
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The engine dies completely at 3000 RPM. As though the ignition is turned off. Revs drop to 2700 and it fires up again on its own (Don't have to hit the starter) Behavior is the same on the road or in neutral parked in the driveway.

When it dies, teh tacho stays alive and follows revs down as the engine spins down.

Start and idle are good. Acceleration is strong without misfire or hesitation, right up to 3000 RPM.

No difference cold or hot.

Problem has just begun. No previous problems.

Around the time it began the car was run out of gas. and refilled. Have changed the fuel filter on the off chance that crud from the bottom of the tank had blocked it. No change.

I have the Ford Power Train Manual and have followed the diagnostic flow chart. There are no fault codes from the engine management system (I am using a VOM to read the codes).

Both the Key On-Engine Off test and the Key On-Engine On tests show no codes. I have tried the Code Erase thinking that might be a computer reset. No change.

Have checked the yellow-Blue wire at the coil and that stays solid 12 V when the engine quits.

Would appreciate any pointers!!!

Cheers
Jul 7, 2008 at 8:06 PM
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SERVICE WRITER
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I'll throw in my 2 cents...might only be worth this, but anyways...

Take off and flip over the air inlet tube to check for splits.

Also, check the crank key way for slop.

Look for bad grounds on the thermostat housing. The bolts holding the housing to the head may have enough corrison that the bracket held on by them that is used as a ground point may not getting a
good ground. If so, remove and clean the bolts and housing.
Jul 8, 2008 at 5:14 AM
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PLAP
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2carpros suggested the items below. Response: No, No and No

Air Tube solid and complete. No cracks
Crank Key has no slop
Ground is good. Measured with low Ohm meter at 0.05 ohm. Bracket and bolts are clean and no corrosion.

[quote:fa12a38a85="Service Writer"]I'll throw in my 2 cents...might only be worth this, but anyways...

Take off and flip over the air inlet tube to check for splits.

Also, check the crank key way for slop.

Look for bad grounds on the thermostat housing. The bolts holding the housing to the head may have enough corrison that the bracket held on by them that is used as a ground point may not getting a
good ground. If so, remove and clean the bolts and housing.[/quote:fa12a38a85]
Jul 8, 2008 at 5:28 AM
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SERVICE WRITER
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What is the fuel pressure gauge showing for specs from the time it gets up to the stall and back to the re-start?
Jul 8, 2008 at 6:02 AM
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PLAP
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[quote:bf8d4459aa="Service Writer"]What is the fuel pressure gauge showing for specs from the time it gets up to the stall and back to the re-start?[/quote:bf8d4459aa]

Thanks for the follow on suggestion.

It will take me a little to round up a T-Piece so I can insert the Fuel Pressure Gauge.

Be back when I have done that

Cheers
Jul 8, 2008 at 3:55 PM
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PLAP
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Fuel Pressure checks good. Ignition checks good.

Since last post I have taken the car to the dealer and paid out $1000 for them to replace the Throttle Position Sensor and have the computer checked/repaired.

Worked fine for three weeks. The problem has now returned. Car has been back to the dealer and they now say O2 sensor and catalytic convertor. I don't think they know what they are doing.

Car is now running rough, on 3 cyclinders. Starts fine. Idles fine. Cuts out completely at 3000 RPM when cold, 2500 when cold. Restarts on its own when revs drop by 500 RPM.

Still no codes from the computer.

I woudl welcome any other suggestions.
Aug 27, 2008 at 3:46 PM
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RDIUS
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Most likely the Timing Belt or Chain is loose. Even a small amount is enough to stall the engine. Starts, runs, quits, then starts again. Also can cause alternator to charge oddly, even causing battery damage over a few years. You'll never notice it until the timing belt has loosened enough to be noticeably off. Best to keep it on time as much as can do so.
Sep 3, 2019 at 11:05 AM
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STRAILER
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Excellent addition to this thread! Please feel free to help out whenever you are on the site :)
Sep 3, 2019 at 12:02 PM
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CAWOOD
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I've had trouble with my 1992 Capri engine dying suddenly on hot days without warning. If I wait until the engine cools it will start and run fine. I changed the coil and no help. Now the problem has happened in cold weather and will not start. The coil tests good by still no fire to the plugs. Someone suggested replacing the engine control module (igniter) but it is expensive and I can't test it and I don't want to waste my money. Any suggestions?
Sep 3, 2019 at 12:03 PM (Merged)
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RASMATAZ
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Pull the coil wire from the distributor and ground it to the engine and have helper crank engine over-do you have spark?
Sep 3, 2019 at 12:03 PM (Merged)
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CAWOOD
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[quote:aa2abe719f="rasmataz"]Pull the coil wire from the distributor and ground it to the engine and have helper crank engine over-do you have spark?[/quote:aa2abe719f]

No spark but there's power to the coil and the coil tests good.
Sep 3, 2019 at 12:03 PM (Merged)
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RASMATAZ
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Test the distributor pick up coil if okay the last place will be the ignition control module
Sep 3, 2019 at 12:03 PM (Merged)
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[email protected]
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while driving, car lost power. This happened a couple of times and then it shut off. Got new catalytic converter and drove home but the next day, it happened again. This time they said it was the fuel pump. New fuel pump, the next day, it happened again. Towed again and told it was the distributor. After new distributor, distributor cap, plugs and wires, the same problem. We are out about $1,000.00 and the car still has the same problem. Seems like it will start after sitting a while but is going shorter periods of time before shutting off.
Sep 3, 2019 at 12:03 PM (Merged)
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HMAC300
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This sounds like an IG relay or ignition switch is heating up and failing. Here is the location of the relay. Also, check for power through the ignition switch when the car stalls.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

and

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Check out the diagrams (below).

Please let us know what you find. We are interested to see what it is.

Cheers
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Sep 3, 2019 at 12:03 PM (Merged)
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CRAZYGANGSTA
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My problem was the IG relay it was super hot when I touched it.
Sep 3, 2019 at 12:03 PM (Merged)
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DAKOTACROSE
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Also when the vehicle is in park the idle will rise and drop till it drops so far that it does
Sep 3, 2019 at 12:03 PM (Merged)
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JACOBANDNICKOLAS
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It sounds like you have a bad idle air control valve (if fuel injected) or a vacuum leak if your car has a carb and not fuel injection.
Sep 3, 2019 at 12:03 PM (Merged)
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2CP-ARCHIVES
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1991 mecury capric keeps shutting down. has a new fuel pump and ignition modual , runs a minute or so then stalls out again. wait awhile and it starts up and shuts off
Sep 3, 2019 at 12:03 PM (Merged)
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HMAC300
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scan for codes and check fuelpressure then try restting your anti theft. i'm not sure how to do it on your car.
Sep 3, 2019 at 12:03 PM (Merged)
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TREETOPSTILLS
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I recently replaced my starter because of a intermittent starting problem that grew worse, I would have power, but no switch sound and starter would not turn over. After the starter was replaced, I have the sound of the starter engaging,but when I go to turn the starter on, I loose the noise, clock, warning lights, but the starter does not turn over. I had a time when I drove thru a big puddle(Oregon)and the car won't turn over, possibly related? Thx
Sep 3, 2019 at 12:03 PM (Merged)
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RASMATAZ
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Check and test the stater relay, transmission range switch and ignition switch.
Sep 3, 2019 at 12:03 PM (Merged)
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TREETOPSTILLS
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Thank you, quick response,will check and post back
Sep 3, 2019 at 12:03 PM (Merged)
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TREETOPSTILLS
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Found the 6 pin starter relay behind the head light, checked for continuity between the points two points showed 40 ohms between them (good= 50-120ohms ?suspect?) and the others showed no continuity. Looks like the relay is bad?
Sep 3, 2019 at 12:03 PM (Merged)
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JACOBANDNICKOLAS
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that is what it sounds like. However, since you loose all power when you turn it to the start position, check to make sure the battery terminals are clean and tight as well as the ground to the engine block. A starter relay wouldn't cause you to lose power to other electrical components.
Sep 3, 2019 at 12:03 PM (Merged)
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BOOZE3
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car has 160000 miles, timing belt was replaced @ 110000 miles, replaced cap & rotor plugs & wires shotly after i bought it @ 147000 miles, i was driving home on the highway 65mph and the tach jumped from 2700 rpm to 3200 rpm for an instant then ran fine then about 1/2 mile down the road the car shut off. got the car home, it started for about 30 seconds then would not start. the next day it started for about 2 minutes then stalled. i thought it was the fuel pump, replaced it and the filter mounted on the firewall. i checked to see if i was getting fuel it and it is. still the car will not start. could this be electrical or something else common for these cars?
Sep 3, 2019 at 12:03 PM (Merged)
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FIXITMR
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ignition module or coil? when it wont start can you hear pump and see spark?
Sep 3, 2019 at 12:03 PM (Merged)
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BOOZE3
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I hear the pump but haven't checked the spark
Sep 3, 2019 at 12:03 PM (Merged)
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BOOZE3
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I know that the pump is working but there is no spark.
Sep 3, 2019 at 12:03 PM (Merged)
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MERCCAPR1992ME
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we used a test light which flickers at the iginition coil and we get a yellow spark at plugs, not blue, we get a reading at the ignition control module on top of the distributor only on one end. so not sure what to replace. suggestions?


we have replaced both the iginition module and the ignition coil, we have sprayed carburator cleaner into the intake and the car turned over but would not stay running, we checked the fuel shut off valve and it is firmly depressed so what is next to check?
Sep 3, 2019 at 12:03 PM (Merged)
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DOCFIXIT
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I would replace coil without proper spark voltage nothing but coil is problem
Sep 3, 2019 at 12:03 PM (Merged)
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MERCCAPR1992ME
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we just replaced the ignition coil. it started several times in the yard then we went to the store, when we came out to leave the car would not start so we rolled down the hill to the house. its been sitting now at the house and still wont start after an hour. now what?
Sep 3, 2019 at 12:03 PM (Merged)
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DOCFIXIT
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Have you checked for spark again? is coil wire on good? if spark spray some cabr cleaner into intake see if it lights.
Sep 3, 2019 at 12:03 PM (Merged)