1G 91 Talon no spark?

[DiamondStar90]

Hey guys I'm dealing with a 91 fwd talon with a no spark issue.

I already changed plugs, I tried getting 3 different CASs. I had key on and turned the CAS by hand and still no spark.
Changed the transistor near the coil pack.
Changed the ECU and still no luck.
I unplugged the connector to coil and the top one lights up with a test light but other two don't.

Is this normal?
What else should I try?

 

[NHerron]

See if any of your sensors have power. Example, take the CAS connector off and probe between pins 3 & 4 with key on. Or check any of the emissions solenoids. If you don't have power anywhere, suspect the MPI relay or it's control circuit.

 

[DiamondStar90]

There is no crank position sensor it's a 1g and ill try probing 3 and 4 and hey can you use 2g coil setupin a 1g just to check coil ?

See if any of your sensors have power. Example, take the CAS connector off and probe between pins 3 & 4 with key on. Or check any of the emissions solenoids. If you don't have power anywhere, suspect the MPI relay or it's control circuit.

Hey where is the mpi relay? And what does it look like?

 

[NHerron]

These are the pins to check by the way:
http://www.roadraceengineering.com/eclipsetech/justin/CASwiring.gif

And the MPI location:
http://www.dsmtuners.com/forums/new...rain-car-will-not-turn-off.html#post151714132

Description:
http://www.dsmtuners.com/forums/newbie-forum/263224-mfi-mpi-relay.html

 

[steve]

Have you verified that the ECU works?

Lets see what I can find by searching my old posts.

No CEL during the first five seconds after you turn the car on indicates that the ECU isn't powering up.
The CEL should turn on, the factory boost gauge should move to zero, and the CEL turn off after 5 seconds. Once you start cranking the starter the factory boost gauge should move down into the vacuum range and then return to 0 once you release the key.

On a 1G.

Make sure you have 12v at the MPI fuse on the positive battery terminal?
Then check to make sure you get 12v at pin 103 on the ECU. It comes from the room fuse #19 next to drivers left foot.

The ECU expects to get 12v at pin 110 from the ignition switch when you turn it to run. In response it will pull ECU pin 63 low to turn on the MPI relay. The MPI relay then applies 12v to ECU pins 102 and 107 and the ECU if it's working correctly will boot up, turn the CEL on while the rest of the dash lights go through bulb check and then turn the CEL off.

If you don't have 12v at pin 10 of the MPI relay the ECU will not power up. If you don't have 12v on pin 103 for backup power the settings for long term variables like fuel trims will reset each time you turn the car off.

 

[DiamondStar90]

Have you verified that the ECU works?

Lets see what I can find by searching my old posts.

No CEL during the first five seconds after you turn the car on indicates that the ECU isn't powering up.
The CEL should turn on, the factory boost gauge should move to zero, and the CEL turn off after 5 seconds. Once you start cranking the starter the factory boost gauge should move down into the vacuum range and then return to 0 once you release the key.

On a 1G.

Make sure you have 12v at the MPI fuse on the positive battery terminal?
Then check to make sure you get 12v at pin 103 on the ECU. It comes from the room fuse #19 next to drivers left foot.

The ECU expects to get 12v at pin 110 from the ignition switch when you turn it to run. In response it will pull ECU pin 63 low to turn on the MPI relay. The MPI relay then applies 12v to ECU pins 102 and 107 and the ECU if it's working correctly will boot up, turn the CEL on while the rest of the dash lights go through bulb check and then turn the CEL off.

If you don't have 12v at pin 10 of the MPI relay the ECU will not power up. If you don't have 12v on pin 103 for backup power the settings for long term variables like fuel trims will reset each time you turn the car off.

Hey which one is the #19 fuse cause the cap isn't labeled

I turn the key and crank and I can feel the mpi relay click on and off by the way

Hey new updated I got power to everything as you listed Steve except pin 102 or 107

 

[steve]

Hey new updated I got power to everything as you listed Steve except pin 102 or 107

Then the MPI relay isn't switching the power from pin 10 to the outputs on 4 and 5.

Back to http://www.dsmtuners.com/forums/newbie-forum/263224-mfi-mpi-relay.html to check why.