CAS is sensitive to touch, resulting in engine dying...Why?!

[chalander]

...::Solved, diagnosis - broken ground wire behind plug for CAS. Solution - Resoldered and wrapped the ground wire::...

With my cam angle sensor hooked up my car runs and idles fine, my afr's are a little off but that is irrelevant to the problem I am about to describe.

Today I had my car idling and was going to set the timing after it had warmed up to operating temp. Surprisingly as soon as I loosened the last mounting bolt for the CAS, the car immediately died.

Now if I wiggle the cam angle sensor after my car has died I can hear the fuel pump priming as if the ignition was being toggled on/off...wtf...by wiggle I don't not mean by rotating clockwise or counter clockwise it rather by pushing it towards the timing cover.

IIt doesn't do seem like a loose connection in my wiring harness that connects to the CAS because if I wiggle the wiring it doesn't give me any symptoms, rather it idles without being phased.

Also I know for a fact that the CAS is not losing a physical connect with the spline in the end of the exhaust cam because once wiggled the cars starts and runs fine and has the same timing that i initially set it to. If it had become disconnected at all then the car would be on a different time when it wiggle it back to reconnect. Not that there is much "play" in me wiggling it for it to disconnect anyways.

What would cause this??

[float_6969]

It sounds to me like an internal issue with the CAS. It's probably on it's way out.

[boost_boy]

He's right, it's history. Time for another one.

[chalander]

Thank you for the valued replies.

I did a bit more trouble shooting today and here is what I find out...
I took off the CAS from the timing cover (still connected I wiring harness) and then touched the CAS unit to my intake manifold. Sure enough the fuel pump came on again. It seems that my CAS is having issues with a bad ground. I attached a small ground cable from the CAS to the intake manifold and it solved my problem. If this doesn't sound right please chime in, otherwise I'm going o move on to my next issue in diagnosing and fixing my car.

[boost_boy]

We forgot to ask you, did you ground the car properly. The CA requires good and clean grounds. You may have solved your own problem.

[float_6969]

Yea, if that fixed the issue, you have grounding issues.

[chalander]

Mind pointing me in a direction of which grounds I should check/install? I know that is a difficult question to answer because the vehicle isn't infront of you but maybe I could get steered in the right direction to some basic tests. correct me if im wrong but i should be measuring the ohms between different grounded contact points, i.e. engine manifold to chassis, negative battery ground to chassis, ecu ground to chassis, engine timing cover to block, etc...

My only modification that would possibly pertain to this issue is a relocated battery which is now in the trunk.

Thanks for the heads up to check my vehicles earthing!

[blownhemi]

Yea, if that fixed the issue, you have grounding issues.

According to the FSM, the CAS sensor electronics get their power supply (+12V, ground) from the harness connector. Any idea why the sensor housing would need a separate good ground as well?
Touching the CAS to a good ground restarts the fuel pump... sounds more like a weird electrical short, that puts the ECU into reset. Maybe a short inside the CAS between the housing and the electronics. I'd check:
- amps flowing (shouldn't) between your good ground point, and the CAS housing. Just put the amp meter in there instead of the wire, you should hear the pump reset the same way, as when you touched it to the intake. Highest amp setting, going towards the lesser amp setting, until you reach the lowest amp setting, and still zero amps flowing

I understand, that it works now, but it's still weird, and doesn't quite feel right, at least to me. I suppose you don't have another CAS you could try, but without the extra ground wire?

[boost_boy]

Although I do belive you still have a bad crank angle sensor, your engine should've provided enough ground as well as the ground provided in its harness. Start at or around your engine's harness looking for cut black wires or grounds that are not attached. And also look for black wires that are not grounded or attached near your dash connector as well as the ecu's blue ecu connection.

[chalander]

Thanks for sharing that testing procedure blownhemi, that makes sense. Also I do have an extra CAS, I will try the 2nd CAS to see if shares the same symptoms, also I will try that testing procedure to isolate and repair any bad ground I come across on my search. I'll ensure to look EXTRA close at the blue ecu connector wiring along with the dash connector. I won't be able to look at it until Monday.

[chalander]

Quick update, I tried my second CAS and it shared the same symptoms. I measured the amps flowing from the CAS to my intake mani and it measured 1.1 amps and 8.1volts - as soon as I touched the CAS unit to the intake mani both reading went to 0 because the CAS was then grounded (fuel pump primes).

One earlier comment that caught my attention was that my ecu may be resetting itself when the CAS becomes physically grounded. I observed my ecu lights when I grounded the CAS unit, the fuel pump primed as I described earlier but I noticed that for the amount of time that the pump was priming the ecu red light would turn off then once priming stopped it would turn back on, the green light remained on consistently. When I turned my ignition from the off to on position both ecu lights came on and stayed on during and after the fuel pump priming.

I have checked the blue ecu plug wiring, the dash plug wiring, majority of engine grounds that I could find both visually and via the FSM. The only somewhat bad ground I could find was the one for my starter, it is only half intact where the wire meets the clip, I will be redoing this tomorrow, but doubt it will provide any results.

Also I tried disconnecting my igniter and drop resistor to see if the CAS amp measurement would differ, but it didn't.

I also noticed that the voltage across the battery terminals would drop from 12.3 to 11.3 when I toggled the ignition from off to on. ( the voltage is a bit low for my battery but I has the ignition on for quite some time while troubleshooting so it probably drained the battery a bit, the battery is only a year old and tested good at a shop 3-4 months ago)

[cbh148]

So swapping out the CAS didn't help.

Got an extra wiring harness you can swap in to see if the problem goes away? Or heck, another ECU?

If you lived near me, I'd let you try my harness/extra ECU.

[chalander]

To my knowledge, I don't live near anyone else that has a ca18det. I live near Seattle, WA.

And no I do not have another harness/ecu to try

[blownhemi]

Quick update, I tried my second CAS and it shared the same symptoms. I measured the amps flowing from the CAS to my intake mani and it measured 1.1 amps and 8.1volts - as soon as I touched the CAS unit to the intake mani both reading went to 0 because the CAS was then grounded (fuel pump primes).

That's just too much current. That sounds like a short. But I'm completely baffled as to how the CAS housing gets to 8.1 volts normally (since both CAS's are doing this), when the CAS itself is only connected to the car's electrical system via the CAS connector. The only thing I can think of, is that maybe the CAS housing and the sensor ground are connected internally from the factory AND there is a miswiring or damaged wiring /insulation somewhere. I'm away from my car and spare CAS, so I can't test the former... the weekend soonest.

Did you measure voltage on the CAS harness, too, by any chance? If not, the CAS troubleshooting part of the FSM will tell you which connector pin should be GND, and shich one should be 12V. I'm betting the harness connector that should have continuity to ground is going to show 8.1V between it and the battery ground/negative.

One earlier comment that caught my attention was that my ecu may be resetting itself when the CAS becomes physically grounded. I observed my ecu lights when I grounded the CAS unit, the fuel pump primed as I described earlier but I noticed that for the amount of time that the pump was priming the ecu red light would turn off then once priming stopped it would turn back on, the green light remained on consistently. When I turned my ignition from the off to on position both ecu lights came on and stayed on during and after the fuel pump priming.

I have checked the blue ecu plug wiring, the dash plug wiring, majority of engine grounds that I could find both visually and via the FSM. The only somewhat bad ground I could find was the one for my starter, it is only half intact where the wire meets the clip, I will be redoing this tomorrow, but doubt it will provide any results.

Also I tried disconnecting my igniter and drop resistor to see if the CAS amp measurement would differ, but it didn't.

I also noticed that the voltage across the battery terminals would drop from 12.3 to 11.3 when I toggled the ignition from off to on. ( the voltage is a bit low for my battery but I has the ignition on for quite some time while troubleshooting so it probably drained the battery a bit, the battery is only a year old and tested good at a shop 3-4 months ago)

What do you know about your car's CA conversion history, with regards to wiring? Did you buy it like it is?

[chalander]

I did not measure the harness, I will though.

Regarding the history of my s13 ca18det swap, I purchased it from the guy who did the swap. I feel he did a legitamate job, all the wires that were cut and reconnected were soldered and taped with electrical tape, or with heat shrink wrap. I have had the transmission out once for a clutch replacement and another time I pulled both the transmission and engine out as a whole via the top of the engine bay to replace the head gasket with a MLS w/ARP studs.

I have another thread going which covers all the trouble shooting I've done on my car, not that I expect people to read it in reference to this thread. I started this thread sepereately because I knew I would need detailed advice on specifically the CAS and it's current symptoms. But I have a feeling once I fix this problem everything should atlast come together.

[chalander]

I found the problem, the ground wire behind the plug for the CAS had become corroded from moisture (reboots owner used electrical tape rather that shrink wrap). In result, it was dating apart and at last broke when I peeled back the rubber plug/wire boots.

I tested for this using the audio alert continuity check on my multi meter, when testing the ground terminal on the CAS plug i wiggled the plug and sure enough am intermittent beep occurred. Upon visual inspect the problem was obvious.

My CAS no longer primes the fuel pump when contact with a good ground.

Thanks everyone, for pointing out that I had a ground issue as well as sharing the testing procedures. Hopefully this will help someone else in the future who encounters the same problem.

[float_6969]

Thank you for posting how you solved the issue!

[blownhemi]

And not that it matters anymore, but the CAS housing is in fact connected to the CAS sensor ground in the harness. In unrelated news, my CA suddenly has no ignition. Good times!