420A 420a ECU woes

[ThunderChild]

im not sure if this will be in the proper spot, but it seem appropriate. please move as needed mods, thanks!

so, i did some work for a guy, swapping in a newer (non-effed) motor for his 96 GS. swapped motor, new cam and crank sensors, new coil, plugs, wires...etc.

so, i get no spark after the install. this guy said the car ran fine before, then stopped one day. thats why he had me swap it, told me his mechanic said he had no compression on cyl #1. well, turns out he had a BHG and had thrown a rod on #1, destroyed piston, catastrophic failure ensued.

so, since i had no start, it start testing the sensors and harness. harness has proper voltage going to sensors (9v-signal-5v). i get pulsing 5-0-5-0-5v signal on cranking. coil has proper resistance.

now, i get no 12v signal going to the coil, and no firing signal from the ecu. checked wires all the way back to the ecu, good continuity and resistance is next to nill. no breaks or opens anywhere. ASD relay and fuel pump relay are in good working order. i know im getting fuel as i have pressure at the rail, plugs are wet with fuel after cranking and i have injector pulse.

now, i jumped the ASD relay (30-86 i believe?) and i got power to the coil. so i knew the PCM wasnt grounding the relay. thought to check on more thing, so i turned key on, no check engine light. tried another PCM, same deal, nothing.

so im wondering if anyone can shed some light on this thing. it cranks fine, gets fuel, just looking for the spark. need to know where the PCM gets its ground from.

motor grounds are good too (bellhousing, intake manifold, motor mount and on the exhaust.) any thoughts?

were going to try another PCM, but past that im stumped.

 

[And_44]

Sounds like an ECU issue. But I've read other 2g owners having a start issue with the coolant temp sensor not working.

 

[VelocitàPaola]

I'd suspect there's a break in the wiring between the ignition coil and ASD relay. Both the coil and injectors are powered from the ASD relay, so if the injectors are working, the ASD relay must be too.

 

[ThunderChild]

kinda my thought too. i hate chasing wires, but that looks like the case. or i could just run a new jumper wire, but thats a band-aid IMO. having pneumonia is really cramping my work ability. been out for 5 days and its just now getting to the point that i can move without alot of grief. ill check the wires again, and try a new ecu (owner picked another up) and see what i can find. its severely aggravating tho.

thanks guys!

 

[Spaz5spd]

I'm having similar issue, looking to purchase a new ecu from autozone, 20% discount , but there are several ones with different numbers as well as ones with an A : think those are for automatics: can anyone help me before I purchase the incorrect one