could i have a bad ecu?

[davetheman81]

i have a 92 talon awd bone stock, the car hesitates and jerks when accelerating like a misfire, it runs very rich, many relay under the hood go off buzzing like crazy as well as the isc when you just out the ignition on. so far i have replaced all plugs and gapped correctly, plug wires, coil, resistor, and did a boost leak test holds 30 psi , compression test 173,171,170,171. I never get any cels but when i put my ignition on the cel light doesnt light up like the other lights so it might be disconected. The ecu is an un modified 92 non eprom, also when the car jerks and hesitates the exhuast pops, any help would be great, im thinking ecu now?

 

[ajpm26]

did you test the isc motor? its really simple and easy to check, also, pop off the cover on the ecu and see how it looks.

 

[gofer]

Sounds like the connector on the CAS might be loose or the CAS itself is bad. Try zip-tying up the CAS connector to the CAS itself, ensuring it can come loose under acceleration and go for a drive.

Your CAS has four wires going to it, a 12v signal and ground the other two are signal wires for the TDC and CAM inputs to the ECU. To test them you'll have to pull the CAS off the head and turn it by hand, this will allow you to test the signals with a multimeter as you spin it. Both the CAM and TDC signal wires should read up to 5v as you spin the CAS, the CAM signal wire pulses 4 times per revolution and the TDC pulses 2 times.

Heres a pin out of the CAS connector going to the ECU so you can check continuity of the wires and know which wires to test for the CAM & TDC pulses.

ECU Pins to CAS connector Pins -

• CAM Signal wire (YEL): Pin 2 at the CAS (4 pulses per revolution)
• TDC signal wire (WHT): Pin 1 at the CAS (2 pulses per revolution)

Post up your results.