Engine quits at 3000 RPM

Tiny
PLAP
  • MEMBER
  • 1994 MERCURY CAPRI
  • 4 CYL
  • FWD
  • MANUAL
  • 120,000 MILES
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
Monday, July 7th, 2008 AT 8:06 PM

31 Replies

Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
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.
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Tuesday, July 8th, 2008 AT 5:14 AM
Tiny
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.
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Tuesday, July 8th, 2008 AT 5:28 AM
Tiny
SERVICE WRITER
  • MECHANIC
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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?
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Tuesday, July 8th, 2008 AT 6:02 AM
Tiny
PLAP
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  • 6 POSTS
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
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Tuesday, July 8th, 2008 AT 3:55 PM
Tiny
PLAP
  • MEMBER
  • 6 POSTS
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.
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Wednesday, August 27th, 2008 AT 3:46 PM
Tiny
RDIUS
  • MEMBER
  • 3 POSTS
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.
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Tuesday, September 3rd, 2019 AT 11:05 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,840 POSTS
Excellent addition to this thread! Please feel free to help out whenever you are on the site :)
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Tuesday, September 3rd, 2019 AT 12:02 PM
Tiny
CAWOOD
  • MEMBER
  • 2 POSTS
  • 1992 MERCURY CAPRI
  • 4 CYL
  • FWD
  • MANUAL
  • 120,000 MILES
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?
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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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?
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
CAWOOD
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No spark but there's power to the coil and the coil tests good.
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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Test the distributor pick up coil if okay the last place will be the ignition control module
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
JMELANDE
  • MEMBER
  • 1 POST
  • 1991 MERCURY CAPRI
  • 16,100 MILES
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.
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
HMAC300
  • MECHANIC
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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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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
CRAZYGANGSTA
  • MEMBER
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My problem was the IG relay it was super hot when I touched it.
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
DAKOTACROSE
  • MEMBER
  • 1 POST
  • 1985 MERCURY CAPRI
  • 40,000 MILES
Also when the vehicle is in park the idle will rise and drop till it drops so far that it does
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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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.
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,542 POSTS
  • 1991 MERCURY CAPRI
  • 118,000 MILES
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
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Scan for codes and check fuelpressure then try restting your anti theft. I'm not sure how to do it on your car.
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
TREETOPSTILLS
  • MEMBER
  • 3 POSTS
  • 1991 MERCURY CAPRI
  • 10,600 MILES
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
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check and test the stater relay, transmission range switch and ignition switch.
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Tuesday, September 3rd, 2019 AT 12:03 PM (Merged)

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