GM CSI Compression Sense Ignition

[rik1083]

Hi. I'd love to move to sequential injection with the advent of MS-III. My car as standard has sequential injection & wasted spark. It doesn't have a cam sensor, but an electronic module to analyse spark plug resistance on waste spark events... and from that, it outputs a camout signal. I currently have removed this module and just trigger the coil pack as regular waste spark, but I can easily put it back on.
Do you think this camout signal will be compatable with MS-III?

detailed article here http://www.speedsterclub.nl/bibliotheek ... ie/csi.pdf

[jsmcortina]

Does the connection to the coilpacks interfere with that system? The output looks like a regular cam signal, so if there's no collision between Megasquirt coil control and that module, then it ought to work.

James

[rik1083]

it doesn't interfere, I can connect one of the pins to +12v, another to 0v and then another two of them for the coil triggers, and then there are two that are n/c (the camout and ref I presume)
I think the problem factor may be that on overrun fuel cut it says it doesn't output a signal (doesn't quite make sense to me since the cylinder will still be compressed and pressurised, just no fuel in it), but that's what it says in the doc.

How does MS/3 handle loss of sync on cam sensor (but still has sync on crank)?

[rik1083]

sorry, that's from another doc i have..

Special Conditions
The PCM needs to take into account
engine operating conditions during which the
in-cylinder pressures for the pairs can be
nearly equal. During deceleration, the
pressure of the compressing cylinder can be
as low as, or lower than, that of the cylinder
on its waste stroke. This condition would of
course render the CSI signal information
invalid. For this reason, the PCM will
consider the CSI signal valid only during
certain MAP ranges.

http://www.norcal-cobras.com/GTM/gm-tec ... 6_02_e.pdf