87 GXL S4, fresh rebuild on everything -
CAS out of engine - Coils and injectors both fire when CAS spun by hand
CAS installed in engine - spark consists but I lose injectors
Fuel Pressure is perfect so it's getting fuel, am having an issue where pump won't turn off on it's own though, it'll trigger from AFM plate opening, jump connector, and engaging the starter
Engine Cranks just fine, but zero fuel due to injectors not firing, tachometer bounces when cranking so I know the CAS is doing half of it's job (firing the coils)

Have been having this issue for awhile and it's electrical related but just not sure what's wrong with my circuit. I know when the CAS fires out of the hole and not when in there is ground fault in the circuit but I need some help finding it.

Here are my test results from checking continuity and voltage at the ECU at Plug #1 with a DMM. Would like to see some results from a running car and compare, I know it's a hassle if it's all together to pull the carpet and cover but it'd be a huge help in me figuring this issue out.

RESULTS IN NEXT POST!

Again looking for some results from a running car to compare with.

Thanks ahead of time,
Brandon

 

Here are the results, couldn't insert image when editing




Brandon

 

So with my CAS unplugged and the Engine Harness 4 pin plug unplugged from the Front Harness 4 pin plug I tested the continuity from the 4 terminals to the body as a ground.

Cable is totally disconnected except for the shielded ground - For wires B and W i got .4xxK ohms and for R and G I got 3.2M ohms. Not entirely sure exactly how shielded cables work but this to me seems not good, if all my wires are grounded then the signal can't reach the ECU and fire my injectors.

If anyone knows this to be true or wouldn't mind doing the test themselves (much easier than testing voltage and continuity at the ECU I know) it would be greatly appreciated and if confirmed I can simply make a new cable for the CAS and start this car up for the first time finally.

Brandon

 

Does the ECU have any codes? FC3S Pro v2.0:&nbsp How-To - Zenki FC3S Error Codes The S4 is very very basic check engine light (OBD) system but it will tell you if something is unplugged/in failsafe mode. There is no failsafe for the crank angle sensor, so if you have a code for it then you know you've got a wiring problem.

 

No codes from the ECU, turns out even though the CAS tested within specs listed in the FSM it's still bad, got another CAS and I have fuel injectors now with the CAS installed in the engine.

The issue is when the CAS meshed with the gear inside the front cover it lost its ability to send the signal for the fuel injectors. I don't know how, I can't explain how, but that's what the issue was.

A bad CAS that passed FSM tests.

Brandon