Lets understand the CAS, spark & fuel ands lack of spark

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StanTheMan
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Lets understand the CAS, spark & fuel ands lack of spark

Postby StanTheMan » Sun Jul 01, 2018 11:45 am

The CAS on the NA6's & NA8's.
I'm not telling, I'm discussing to make sure I understand.

The CAS is essentially a more modern Distributor. But has 2 functions.compared to the old Dizzy's

it is there to trigger spark & fuel injectors.

If the CAS is broken. The car doest run.

If however you have fuel but no spark, this would suggest the CAS itself is in working order. The problem with the spark is perhaps elsewhere like faulty old wiring or bad coils or faulty ignitor?

I currently have no spark. I have fuel. last week the car stopped running. no spark. so I changed & wired up COP's.
Car ran yesterday. so correct wiring of COPs is confirmed.

I now don't have any spark.....again.
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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby NitroDann » Sun Jul 01, 2018 12:21 pm

The CAS simply tells the ecu where TDC is.

It has a few slots, so it's not just telling it where No.1 TDC is, but where each cylinders TDC is. It has 4 wires, +12v in, Ground, 4 triggers per CAS revolution for cam output and 2 for crank.

If it's not working you shouldn't get either spark or fuel.

If you get either then it's working but another system is not.

If you're running a stock ecu you're up sh*t creek in terms of diagnostics, good luck.

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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby 3gress » Sun Jul 01, 2018 12:48 pm

There are two types of cam angle sensor.
An optical type with a slotted disc pictured on right, the other(reluctor?) Sensor on left has two plates for ecu signal.
Image
Note on the left type there is an inner plate with tooth just visible below screw head.
You really need an aftermarket ecu to adjust dwell time to run COPS.

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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby StanTheMan » Sun Jul 01, 2018 2:53 pm

Im running ms pnp2
Im using the NA6 CAS which is the one on the right.
Ive checked all the wires on the connectors . There are ok. Definately attached.


Ive adjusted the dwell to 2.5ms it was originally on 3.5ms from the 1.8 basemap
Truth be told i dont know my way around diagnisics within tuner studios. Ill need to do some reading.


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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby StanTheMan » Sun Jul 01, 2018 4:43 pm

Big ƒü¢k up.

I couldn't see the cranking dwell. I figured since every thread i read was about the Megasquirt 3 settings....I thought maybe the MS2 didnt have the setting.

it was hiding in plain view. :oops: :roll:

it was set at 8ms
hope i haven't fried the the COPS

when I was checking for spark today....steam would come out of the spark plug. :shock:
no Idea what thats about ....
but I have a flat battery as we speak.

so maybe.....maybe not
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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby NitroDann » Sun Jul 01, 2018 5:04 pm

8ms is pretty normal, but some coils with ignitors built in have protection circuits.
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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby StanTheMan » Sun Jul 01, 2018 6:12 pm

Ok.....hopefully all good

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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby bartmanftw » Mon Jul 02, 2018 8:47 pm

The CAS tell the ECU what the current engine position is. The two types you find on the NA both give identical signals electrically however one uses optical sensors while the other uses a magnetic pickup.
In Tunerstudio you can use the composite logger function to view the signals and determine if the CAS is working.

Image

Since you say you are getting fuel it sounds more like it is an ignition issue and not the CAS.
You can use the output test modes on the ECU to fire each coil individually (or in pairs if batch ignition) without running the engine. Just stick spark plugs in the ends of the coils and make sure they are touching the valve cover or something else that is earthed. Also be careful not to zap yourself!

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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby StanTheMan » Tue Jul 03, 2018 6:56 am

youre awesome bartmanftw.

thanks heaps
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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby 3gress » Tue Jul 03, 2018 7:44 am

If you have an inductive timing light you can butcher an old plug lead and attach one end to the installed spark plug, the other end you remove the boot and insert the exposed lead wire into the uninstalled coil making contact with the internal spring. You can then attach the inductive pickup around the plug lead and use the test function to test fire coil.
I'm not familiar with MS diagnostic functions but with my adaptronic i can test fire each coil for confirmation of spark using this method.
The steam you mentioned sounds a bit wooly but it may be due to ignition timing being off a little and prematurely firing coil.

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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby StanTheMan » Sat Jul 07, 2018 3:07 pm

The funny thing is....
It started during the week. But didnt run real well. I then stopped it....& it woulnt start again.

I think ive done something not right with the wiring near the ignitor. Perhaps miss understood something in the instructions im a bit of a retard when it comes to electronics. I kow the engine is fine because it started & reved fine at first. Then sometbing died. Unsure what. Next few weeks i will not get much chance to have a look. Ill eventually get it....its just a matter of time



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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby bartmanftw » Sat Jul 07, 2018 4:07 pm

Could it be one of your wiring connections has failed? Have you done the test mode to see if the coils are firing?

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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby StanTheMan » Sun Jul 29, 2018 1:26 pm

Ive checked the wiring with multimeter. They all have power. All earth connetions have power.
Continuing wiring has also been checked on the far side of the connecto
Coil 4& 1 hve continue wiring & 2 & 3. For trigger.
4& 3 have wires for the rpm guage.
The ignitor has been disconnec ted.
Wire 1& 2 leading to connector have been connected
Same with 7& 8.

Im unsure if other wires leading i to the ignitor are supposed to be connected.
Ive also not connectef the rpm guage. Unsure if that is a requirement for engine to run.

Im now suspecting the cops themseves. They are not the usual ones.

There is nothing grabbing the actual sparkplug. Like they do with the leads.

Ocassionally she starts for no reason....but then dies. This is not so much with the ecu....i just dont have any spark. Ivr chrckrd countless times.


Was going to undo the fuel filter....cause its had E85 sitting in gne tank for 10 months. Bit it has petrol. I can smell it & see it on the plugs

Image

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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby StanTheMan » Sat Aug 04, 2018 6:11 pm

PATCHY lives.
Unsure where the problem was. I can only guess.
I dont recall sequence off events. But last week i changed maps...back to the 1.6 and modified it t run on e85.
She runs great. Although lots of work still required.
Shes starting reliable. Tomorrow morning will be another test in cold weather.




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Re: Lets understand the CAS, spark & fuel ands lack of spark

Postby 93_Clubman » Sun Aug 05, 2018 10:36 am

Yay! :mrgreen:


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