LS/VTEC w/ M&W Pro10 ignition is changing timing by itself. From the start to the finish of the dyno session, we noticed a 6 degree retard. The car also seems to be hitting a wall around 9k. Rev limit was set to 9500 but it never made it there. The S300 was constantly disconnecting/reconnecting, even after swapping ECU's and trying a different, shielded, usb cable.

The voltage was dropping at high RPM and misfiring. The dyno's knock sensor was going crazy, but was set so conservatively there is no way it should have been knocking.

Aside from the voltage drop/disconnecting issue, which is probably an electrical gremlin somewhere, what would cause the timing to change on it's own? Distributor contact points messing up? (The stock coil/igniter are gone.)

 

whats the igniton look like in the datalog? i had mine stuck at -17 before because of corrupt map.

 

i don't know what crank pulley ur using but if its a Bseries motor and running the the OEM dampener they tend to break and spin,

 

Used to have that problem with the s300 always disconnecting and ****. I thought it was interferance from my Hondata cpr.
Never did figure it out the motor blew.

 

i used to have a tuner that always blamed my car for his laptop wigging out but mine never had an issue, he just had junk haha

 

It's an ATI.

 

usually a ground or power issue somewhere in the harness you'll have to process of elimination certain parts of the car to isolate go over engine bay then interior then fuse boxes etc... it'll be something simple as always had a few of them in the past

 

It may be the M&W unit. Call a rep and explain your symptoms. Not achieving full RPM potential can be an ignition CD leakage internally. When overworked caps get internal shorting, you can experience random voltage drops. Possibly going momentarily low enough for the S300 to drop out.

No contact points man. Got rid of those in the early 70s.

 

Had the same thing happen before. Tuner blamed my car for random problems we were having on the dyno one day. His laptop kept disconnecting from the ECU. Then the ECU seemed to have went bad, then he put in his own pride and joy ECU that he loved into my car and it fried. We ran out of options so he removed the Neptune Demon board from my original ECU and just put together a tune and burnt a chip for that ECU to see what would happen. The car ran perfect. I returned the Neptune Demon and they replaced it with a new unit and I installed that. Uploaded the tune to that board and it again ran perfect. Just a bad day on the dyno where random junk wanted to be just that, junk!!!