Fresh rebuild CAS issues
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Joined: Sep 2022
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From: Bainbridge island, Washington
Fresh rebuild CAS issues
So I just rebuilt the engine on my s4 n/a convertible, and after putting it back in the car I am having a crank no spark issue. I highly suspect it is an issue with the wiring from the CAS to the ECU and here’s why:
I don’t have spark to any of the spark plugs but I know they are good because I tested them on another car and they worked great.
I have fuel pressure because one of the hoses squirted fuel when I was testing the fuel system so I tightened the clamp.
After I tried starting it the first time and it didn’t work I assumed it was flooded from me cranking the engine to build oil pressure beforehand, but when I took out the plugs and cranked it, there was no fuel vapor. So that means the injectors also aren’t working.
When I crank it over the tachometer doesn’t jump and also the tach would sometimes not work randomly back when the car was still being driven.
I used my multimeter to test if I have continuity from the CAS plug to the engine harness, which I did have on both Ne1 to Ne2 and G1 to G2, and the resistance was within the spec from the Haynes manual.
I read on here that the connector between the CAS and the engine harness can be finicky and some people just hardwire it so I did that.
Next up I used my multimeter to see if I have continuity from the CAS through the engine harness to the plug that connects to the front harness, which I also did for both the G coil and the Ne coil.
so then I went to the plug that goes into the ECU and the Ne coil/hall sensor had continuity but the G one (green & blue wire on CAS) did not have continuity.
Which means that for some reason in the past 10 months that my cars been sitting in my driveway on jack-stands, the wires for just the top Hall effect sensor and only the section that’s in the front harness has some sort of damage/issue/kink. I doubt it’s rodents because all the other wires under the dash look spotless.
So my question is: what do I do next? Tear out the dash and the entire front wiring harness?
Please tell me there’s some other connector or relay or fuse I’m missing so I don’t have to do that.
I don’t have spark to any of the spark plugs but I know they are good because I tested them on another car and they worked great.
I have fuel pressure because one of the hoses squirted fuel when I was testing the fuel system so I tightened the clamp.
After I tried starting it the first time and it didn’t work I assumed it was flooded from me cranking the engine to build oil pressure beforehand, but when I took out the plugs and cranked it, there was no fuel vapor. So that means the injectors also aren’t working.
When I crank it over the tachometer doesn’t jump and also the tach would sometimes not work randomly back when the car was still being driven.
I used my multimeter to test if I have continuity from the CAS plug to the engine harness, which I did have on both Ne1 to Ne2 and G1 to G2, and the resistance was within the spec from the Haynes manual.
I read on here that the connector between the CAS and the engine harness can be finicky and some people just hardwire it so I did that.
Next up I used my multimeter to see if I have continuity from the CAS through the engine harness to the plug that connects to the front harness, which I also did for both the G coil and the Ne coil.
so then I went to the plug that goes into the ECU and the Ne coil/hall sensor had continuity but the G one (green & blue wire on CAS) did not have continuity.
Which means that for some reason in the past 10 months that my cars been sitting in my driveway on jack-stands, the wires for just the top Hall effect sensor and only the section that’s in the front harness has some sort of damage/issue/kink. I doubt it’s rodents because all the other wires under the dash look spotless.
So my question is: what do I do next? Tear out the dash and the entire front wiring harness?
Please tell me there’s some other connector or relay or fuse I’m missing so I don’t have to do that.
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