96 accord, nonvtec. no spark at plugs or coil. installed new icm, still nothing. dug deeper and seems the ecm isnt sending the ignition output signal to the icm to pulse the coil through the yel/grn wire circuit. checked that wire at the icm connector and the pcm connector. im assuming the ecm is supposed to pulse this wire to tell the icm to pulse the coil. bad ecm???? thanks in anvance.

 

getting crank and cam signal also

 

If the resistance across the sensors is within spec then it does sound like it. Might check bone yards for a used ecm. I think car-part dot com will let you put in your info and show you local places and prices.

 

Do you have a Check Engine Light (CEL) ? If yes, get the codes.

If not, I would do some additional checks before condemning the ECU.

1) When you turn the keyswitch from Off to On, does CEL come on for 3 secs and go off?

If CEL comes on for 3 secs and goes off, the ECU self check is good, so w/o any codes, problem is elsewhere.

If CEL does not come on, you could have a ignition switch problem, no voltage to distributor. Check Blk/Yel wire at distributor for 12v to confirm voltage to distributor.

Has coil resistance been checked? Weak or open coil can stop spark generation.

good luck

 

the blk/yel circuit has 12v at dizzy key on, as does the coil. on the grn circuit going into the dizzy which is the primary output control from the icm to coil has 12v while cranking, this wire should pulse, correct? they yel/grn circuit is the pcm input circuit to the icm, has 12v while cranking. this wire should also pulse, correct. also i can probe the yel/grn circuit form the pcm connector with a test light(ultimately putting a ground wire on the circuit) and i get spark at the coil wire telling me the ecm pulses this wire to tell the icm to pulse the coil. no DTCS, and while cranking have rpm signal on scan tool(snap-on brick from my dealership).

 

Suggest checking coil resistances; primary 0.6-0.8 ohms and secondary 14-22 kohms.

If you're getting tachometer output, the ECM must be generating pulses to the ignitor.

good luck

 

did i not just say i can put a ground on grn/yel circuit and get a spark at the coil. the coil is within specs. IS THE GRN/YEL CIRCUIT COMING FROM PCM TO ICM SUPPOSED TO PULSE????

 

Did I not just say the ECM is sending pulses since you are getting tach signal.

Coils sometimes will spark w/ weak spark due to internal shorts that limit voltage output.

good luck

 

the coil is fine, resistance checks fine. and i have swapped it with a known good one. the problem is the ecu is not pulsing the yel/grn circuit to the icu. this circuit has 12v with ko, but should pulse while cranking. which it's not doing. with key on, i can apply ground to suspect circuit and get spark to the dizzy cap. can actually do this while cranking and it will try to run. dont think i can pulse the circuit as quickly as the ecu tho...lol

 

Unless you have an oscilloscope, you may not be able to "see" the voltage pulses that trigger the spark. However, you seem to have eliminated only remaining issue besides ECU.

You can find plenty of used ECU's on ebay or car-part.com. Usually < $30.

good luck