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Cas Walking ?

tmc_2

By tmc_2,
in Engines & Forced Induction

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tmc_2 Rising Star

tmc_2

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Hi guys,

I took my car to get the air/fuel ratios checked out on the dyno and the PFC checked today.

Turns out i have a "walking CAS?" they say thing the backing plate the CAS bolts to is loose some how so my timming is changing every now and then, even though visiually it is bolted and doesnt move.

Has any one experienced this or know why or what is involved in fixing it?

Thanks

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dead32 Mentor

dead32

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nope never had it moove. theres an alloy braket that the cas bolts 2. the retainer bolts for that are under the timming cover. do you have adjustable cam gears? <<possible cause also there could be interference with the crank angle sensor causing it to skip.

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tmc_2 Rising Star

tmc_2

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nope never had it moove. theres an alloy braket that the cas bolts 2. the retainer bolts for that are under the timming cover. do you have adjustable cam gears? <<possible cause also there could be interference with the crank angle sensor causing it to skip.

Is it possible if the bracket bolts where loose ths would cause it to walk? I dont have adjustable cam gears.

By the way on the PFC at idle my base ignition is on 15 and is fine doesnt wander??? when i visually look at my CAS its bolted in the way advaced position. Tuiner told me they didnt wanna tune it till they get the CAS issue sorted but i dont see the problem they are talking about?

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Adriano Grand Master

Adriano

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My cas was farked at one point.

It would hold timing nicely then once on boost loose power.

Turned out the cas was farked, and once it hit boost it would just pull all the timing out, hence not making power. Cas was fixed and was fine

Yep, my 300zx did that, i dont see how the bracket being loose(scary) would cause the timing to change enough to notice, unless the bolts were completely undone, as the bracket is located to the head by dowels, if they are that loose, your timing is the least of your worries.

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tmc_2 Rising Star

tmc_2

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Thats really interesting guys, i had a think about it and yes even ith the bracket was loose i done see it effecting timming much.

So could this be a sympton of fualty CAS itself?

Ive been watching base timming on the PFC handcontroller. It says 15 at idle, now visually the cas in in extreme advance position? does the PFC over ride the physical possition of the CAS and change base timming to what ever its set to?

I might buy a second hand CAS and see how that goes? what do people think?

Thanks guys

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  • 5 months later...
AdamsR33 Mentor

AdamsR33

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The PFC is only assuming the base timing is set at 15deg, you could set it to what ever you want so long as you set the pfc the sameway, eg: say you set the base timing for 20deg but in the pfc its set at 15deg, the pfc assumes its 15deg, it doesn't read what it actually is. so if base timing is 15deg, then you have to set the pfc to 15deg. if its 20deg set the pfc to 20deg, etc etc do you get what i'm trying to say?

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