Checking to see if the CAS is working correctly
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Checking to see if the CAS is working correctly
My car has been going nuts on me recently and Im starting to narrow down my search. Here's what it does -
Bad hesitation at 4k rpms. Car always feels like it has a load on it, so I have to give it more gas than Im used to. Wont boost more than 5psi. When I try and boost/rev past 4k rpms it makes a lot of quick pops out the exhaust. Not loud backfire ones; more the kind you get when you run rich as hell. In neutral the car can build up boost. Problem is its a 5spd.
I changed the spark plugs and that seemed to help some. It didnt solve the problem. I have wires in the mail. I doubt thats gonna fix it though. Since the car can build boost at idle and it doesnt want to go over 4krpms unless i floor it, Im thinkin its something related to the timing. I know its spark related. My best guess is its the crank angle sensor. I checked mine and both look to be in good shape and the metal tab that they read seems to be in good shape, but Im not sure if internally they're blown. I cant test and make sure its not my ecu since I have PFC. How would I determine if the problem was from the CAS?
Bad hesitation at 4k rpms. Car always feels like it has a load on it, so I have to give it more gas than Im used to. Wont boost more than 5psi. When I try and boost/rev past 4k rpms it makes a lot of quick pops out the exhaust. Not loud backfire ones; more the kind you get when you run rich as hell. In neutral the car can build up boost. Problem is its a 5spd.
I changed the spark plugs and that seemed to help some. It didnt solve the problem. I have wires in the mail. I doubt thats gonna fix it though. Since the car can build boost at idle and it doesnt want to go over 4krpms unless i floor it, Im thinkin its something related to the timing. I know its spark related. My best guess is its the crank angle sensor. I checked mine and both look to be in good shape and the metal tab that they read seems to be in good shape, but Im not sure if internally they're blown. I cant test and make sure its not my ecu since I have PFC. How would I determine if the problem was from the CAS?
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Originally Posted by DjRannyKan
does it build full boost at n ???
Basically, neutral just act like any other gear when i give it gas, I just dont move anywhere like I would in any other gear.
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Originally Posted by DjRannyKan
i thought it n it would only buil like 2 psi or something??
If you've ever heard of two stepping (I think thats what its called) it pretty much changes the timing drasticly and dumps tons of fuel into the engine to allow the car to build boost in neutral by putting an artificial load on it (due to the timing being so crazy). My car suddenly thinks it can do this.
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Originally Posted by DjRannyKan
u said your running a pfc?? base maps?? tuned?? do any modifications since the tune??
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Originally Posted by DjRannyKan
u still have the stock ecu?? if so try hooking that up.
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Originally Posted by DjRannyKan
well im just throwing ideas out, do u have a ohm meter?? are u getting spark at all plugs?? coils good?? sorry if these seem dumb.
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I checked the resistance on my coil packs. The leading coil pack is reading 8 ohms between the connectors. Spec is 9.6 - 16 ohms. Could a bad coil pack be the cause of these sort of problems (like making boost in neutral)?
#14
Originally Posted by Gamezilla
I have a voltometer, but I dont know what resistance I should be reading from the CAS. Spark is good. Plugs are new. New wires are in the mail, although I know this wont solve it. Bad wires wouldnt cause me to boost in N. Thats timing related. Only thing that controls timing is the CAS and ECU. If I can eliminate the CAS then that leaves me with just the ECU to worry about.
Just an idea.
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Originally Posted by broken93
Since I'm not sure what you mean by "boost in neutral", i.e. static boost vs fluctuating boost needle, I have seen instances where a CAS that is out of phase will cause a spark to be fired when the intake tract is open igniting the charge in the intake and causing it to burn in the manifold, etc, which would certainly cause your boost gauge to jump to positive pressure a bit (you'd usually hear a thump too from the ignition). I had that problem with a piston engine once.
Just an idea.
Just an idea.
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