Misfiring...please Help!!!

[TommyboyTalon]

I HAVE A 94 TALON WITH A 90 LASER 2.0L TURBO MOTOR. LAST WEEK IT STARTED TO RUN LIKE CRAP SPUTTERING AND MISFIRING. I CHECKED TO SEE WHAT WAS MISFIRING AND CYLINDER 1 AND 4 ARE NOT FIRING. I HAVE REPLACE SPARK PLUGS WITH NGK PLUGS. NEW WIRES, REPLACED THE COIL PACK AND POWER TRANSISTOR, AND CAS (TODAY). I HAVE VOLTAGE AT MY COIL PACKS SO I THOUGHT FOR SURE IT WAS THE CAS. i HAVE NO IDEA. I GUESS MY NEXT STEP IS TO TRACE THE WIRES BACK TO THE ECU.

 

[ryno]

Have you checked the timing? Are the wires good that are going to the CAS?

 

[TommyboyTalon]

All Good, Still No Spark Cylinders 1 And 4.

 

[Ultimatedsm]

You basically replaced all the ignition devices. You can recheck all your ignition devices as well just incase. I have a feeling if it isn't any of the ignition devices, it is your ECU.

 

[TommyboyTalon]

Wouldn't It Just Totally Stop Running If It Was The Ecu

 

[toybreaker]

I've been seeing a pattern of cas failures recently.

The harness connections get corroded and drop the signal off. I strongly recommend a close visual inspection of the cas harness pins. A little work with the radio shack contact cleaner/enhancer may make things all good again.

The ecu's in these cars do some strange things, as well. I've seen a couple of ecu's used for troubleshooting by substitution that had the same problem. .

The best test is your ecu in another car.

Edit; I just saw you've got a 90 motor in a 94. The coil/transistor seups are significantly different, and the interchange of these parts from 90 to 91-94 cars requires that some wires be swapped at the ecu harness, and the coil pack/transistor. The ecu's are also not directly interchangable as well. Please be carefull using 90 pieces on a 91-94 car. Hopefully, somone else can explain the why, I just know you can cause some extra issues between the tach and coil/transistor pack swappifying stuff between the years, without modifying the wiring.

There's several misfire threads running right now. I'd check those out for ideas as well.

 

[TommyboyTalon]

CAN BAD CAPS IN MY ECU CAUSE THIS KIND OF PROBLEM.

 

[sevrus]

i would check the power transistor i just had the same problem. try this...

1 2 3 4 5 6 7 8
-- -- -- -- x -- -- -- " x represents a blank terminal"

to check the side of the power transistor that affects 1 an 4, connect an ohmmeter between terminals 3 and 8 there should be no continuity. when a 1.5 volt battery is connected between terminals 3 and 7 there should be continuity. DO NOT USE MORE THAN 1.5 VOLTS FOR THIS TEST....AND DO NOT CONNECT THE 1.5 VOLT BATTERY FOR MORE THAN 10 SECONDS AT A TIME OTHER WISE THE POWER TRANSISTOR COULD BURN OUT. to check the side of the power transistor that affects 2 and 3 connect an ohmmeter between terminals 1 and 3. there should be no continuity. when a 1.5 volt battery is connected to therminals 2 and 3 there should be continuity. if the power transistor fails either test replace it.

 

[Defiant]

CAN BAD CAPS IN MY ECU CAUSE THIS KIND OF PROBLEM.

TYPING IN ALL CAPS CAN GET YOUR THREAD LOCKED. PLEASE STOP.