Originally Posted by RANDY CORVTE
have 1885 corvette eng l98 i exchanged because other was bad i used all the stuff off old engine on new crate 350 have some problems withthe tpi inj im running to rich and smog was 40.says exeptable is 20 anyways the qwestion ////////????????? The computer needs reset from the dealer to be learned again and clear codes because of disconnection the tbi sensor should be open what deg shut off 10 deg what any way to make fuel not so rich probley has trouble codes chech engine on all digitall help please pandy randy .
What is the crate engine, if it is not a direct replacement for the L98 there can be a lot of problems with the EFI?
Most everyone misunderstands the Learn function of the computer. This is not an unlimited genius capability to define and understand anything bolted underneath the intake manifold. It is a limited function only being able to compare mixture ratio data from the O2 sensor to a map block of originally programmed fueling data and after a period of time seeing these irregularities of being able to make a small change to the block number equating to roughly a 10% change in mixture. It is intended to keep the engine emissions legal for differences of manufacturing tolerance, geographic location, weather changes, and wear. This is a slow process that is lost if the computer is cycled by disconnecting power before the minimum number of observation times have been made to the block number is permantly changed. The block number is not random it is an ID location that tells the computer where to go on the fuel schedule to find a specific on-off time for the injectors based upon sensor input data. If the engine needs a correction that is not included in the block map or is not on the fuel schedule, it obviously can't make that change. If the engine has been modified to a configuration that upsets the sensor data far from what is being expected by the computer, then a new program has to be loaded into the computer for these OBD I units, for the 1996 and up the OBD II jobs they need a pre or post processor added and/or a piggy back ECU employed.
If the crate engine you used is identical to the original L98 but is having EFI problems then it is reasonable to search for a damaged or failed sensor, or a bad connection in the connectors or wiring that was disturbed in order to perform the engine change. A common problem is the thermostat being too cold or the computer's engine temp sensor not functioning. The throttle position sensor adjustment is also a common problem.