How do you invert the CAS?

[j0hn6oo]

I've looked at a bunch of different threads and cant find the answer... I have a rather unique situation to add to this, the car is a 95 GSX but it has a 97 ECU in it. All I had to do to get it running was switch the firing order from 4123 to 3214 and it works fine but everywhere I looked said I was also supposed to invert the CAS signal and I'm unclear on how to do this because there is only 1 pin leading to the ECU (88).

Any help is greatly appreciated.

 

[govproperty]

If you have Dsmlink just select invert cas. But if not go to magnusmotorsports.com then to the tech section. Open the 1g in a 2g file and on page 9 it shows how to properly line up a cas. If you have it lined up correctly then you could turn it 180 out. To be honest I have never heard of inverting a cas with out the 1g swap and if your car is running well I don't know if I would mess with it. When my cas was 180 out I had horrible acceleration. Good luck.

 

[j0hn6oo]

I bought the car with no ECU and put the one from my 97 GST in it and bought an eprom for the GST, so I don't have DSMLink for it. The car runs fine for daily driving but has a bad vibration especially around 5,000 RPM (so bad that I can't keep my foot on the pedal), it also has a jumpy idle between 750-1000 RPM along with hard starts. So I was thinking that the CAS was producing sort of a mirror signal so that the car would run but not run well, thats why I want to invert it. The only other thing I could think of is that the balancing shafts could be out of time. Any ideas?

 

[govproperty]

Do you have a boost gauge with vac on it? I didn't see one in your profile. If you have low vacuum then you could have a air leak causing your idle problem. Bur unless your hitting fuel cut I don't see a boost leak causing high rpm shudder. You should hit up vfaq.com and check your camshaft/ balance shaft/ crank timing. If you search the forums here I am sure you will find a lot of support for eliminating your balance shaft and that would get rid of that being out of time for sure. I don't know much about the 97 ecu swaps though. But you could verify you mechanicals. Are you throwing any codes? Look back the magnus 1gina2g file and on page 8 it talks about converting a 95-96 to 1g. I would assume that it makes a 97 like a 1g cas. You might be able to reverse the pins and get what you need.

 

[j0hn6oo]

OK, I put a 95 EPROM ECU (non dsmlink) into the car and it did make it run a little better. I also tore the whole side off the engine and checked the timing and thats good too.

I was sitting in my driveway today and reved it to 2000 RPM (which is one of the two points where it vibrates the worst) and pushed the clutch in while it was in neutral and the RPM that it vibrates at changed to 1500 RPM so I let it out and the vibrating went back to normal. While still in neutral I pushed the clutch down just until it had some resistance on my foot and the vibrating got alot worse. What could cause this?

And I do have a 30-0-30 vac guage, I'm sure it is a fuel related idle problem, that doesnt concern me, I just want to get rid of the vibrating because it is shaking my exhaust and steering rack bolts loose, I need to tighten them at lease once a week and its getting cold out.