ok, first off i have a 1991 honda civic hatchback and we put a b18a1 block with a b17 vtec head in it. the ecu that came with the engine was already converted to a vtec ecu. but i now have hondata s100 on this ecu. my problem is that i will be driveing down the road and i will get up to about 50 mph and then slow back down and my check engine light comes on and throws a vss code. so i had jim at motorvations in trussvile to take a look at it when i got him to put hondata on it. he did some tests and thought it was the haylo in the guage cluster. my factory tach doesn't work but my speedometer and everything else does. it doesn't effect vtec from kicking in either. so i found another guage cluster and swithched it out. still same problem and the stock tach still doesn't work in this one either. and also jim noticed that there was a circuit that was suposed to have like 5 volts or amps going to the ecu and it was registering 11.5 or something like that. and we couldn't figure out why. does anyone know why this is and how to fix it? we have been working on this for a while now and it has stumped us. any help would be greatly appreciated. thanks.