My car ran without CAS
#1
My car ran without CAS
I was working on my car this weekend. There was a cable that had rubbed against the accessory belt and had split. I decided to go in and solder what I thought was a connection to my air conditioning. Once I got the under cover off I quickly realized that it wasn't connected to my AC at all but was my crank angle sensor. How is this possible that my car could start up and run decent (probably not the best but seemed fine)? It had been running like this for quite a while.
I soldered up the destroyed wires, plugged in the sensor, reset the computer and it ran without the Check Engine light which was there before.
I soldered up the destroyed wires, plugged in the sensor, reset the computer and it ran without the Check Engine light which was there before.
Last edited by Big Boy; 08-04-2008 at 08:51 AM.
#4
Elite Member
iTrader: (21)
Join Date: Jun 2006
Location: Point Pleasant, NJ
Posts: 2,957
Total Cats: 2
On a 97 the engine probably runs off the CAS at the exhaust cam still and the crank pulley trigger is probably used for OBDII diagnostics. Aids in determining what cylinder has a misfire etc.
#8
Elite Member
iTrader: (21)
Join Date: Jun 2006
Location: Point Pleasant, NJ
Posts: 2,957
Total Cats: 2
I believe it's not simply a software setting. I only base that on DIY asking me how I wanted an MSI built recently for an MSM. I opted for the NA CAS setup since I have no experience with the crank pulley trigger.
If you ask me, doing with adjustable cam gears stands more of a chance of screwing up your electrical timing if you are determining timing based on cam position. Typically we determine timing relative to crank position. We just use the cam position to set it because with a fixed cam gear the position of the cam relative to the crank should be identical every time not taking into account timing belt stretching. If you start moving the exhaust cam relative to the crank I would think some compensation would have to be made in electrical timing. If you advance the exhaust cam gear 2 degrees you are advancing the electrical timing too, 4 degrees I think since 2 revolutions of the crank = 1 revolution of the cams.
If you set timing at crank by the actual crank position with crank pulley trigger the electrical timing is locked to the crank position no matter how much you move your adjustable cam gear.
anyone?
If you ask me, doing with adjustable cam gears stands more of a chance of screwing up your electrical timing if you are determining timing based on cam position. Typically we determine timing relative to crank position. We just use the cam position to set it because with a fixed cam gear the position of the cam relative to the crank should be identical every time not taking into account timing belt stretching. If you start moving the exhaust cam relative to the crank I would think some compensation would have to be made in electrical timing. If you advance the exhaust cam gear 2 degrees you are advancing the electrical timing too, 4 degrees I think since 2 revolutions of the crank = 1 revolution of the cams.
If you set timing at crank by the actual crank position with crank pulley trigger the electrical timing is locked to the crank position no matter how much you move your adjustable cam gear.
anyone?
#9
Boost Pope
iTrader: (8)
Join Date: Sep 2005
Location: Chicago. (The less-murder part.)
Posts: 33,052
Total Cats: 6,615
You'll need to build the VR input circuit for the crank sensor (on the '96-'97 cars it truly is a naked VR sensor, rather than an open-collector hall sensor as in the NBs) and you will also need to build a second input circuit and wire up the CMP signal from the CAS (as per a "normal" NA install) to provide an absolute TDC reference.
If you're using an MS2, some fancy software config in MegaTune and you'll be up and running. With the MS1 CPU, you'll need to physically grind off the two teeth which are under the sensor when at TDC and BDC.
And Paul is 100% correct in that the '96-'97 cars use both CAS signals for primary operation, with the crankweel purely for OBD-II misfire detection. Starting in '99, the crankwheel became the primary firing trigger.
If you're using an MS2, some fancy software config in MegaTune and you'll be up and running. With the MS1 CPU, you'll need to physically grind off the two teeth which are under the sensor when at TDC and BDC.
And Paul is 100% correct in that the '96-'97 cars use both CAS signals for primary operation, with the crankweel purely for OBD-II misfire detection. Starting in '99, the crankwheel became the primary firing trigger.
Thread
Thread Starter
Forum
Replies
Last Post
elesjuan
Build Threads
9
11-14-2018 12:18 PM