97 new engine no start

I put a new engine in my 97 and it cranks but won't start. I have a CEL and I don't have a code reader but I did the key trick and I get back a 12 and 25. The 12 I gathered is just saying the battery was dead, which doesn't surprise me since it has sat for 7 months. The battery is charged but weak. But for the 25 this is what I have found "25 Automatic Idle Speed (AIS) motor driver circuit shorted or target idle not reached", any idea what this means? Does it have to do with the IAC?

1997 has OBD-II diagnostics, you should use them. Generic two digit OBD-I trouble codes are not very specific and basically useless.

Naturally you need a fully charged battery, in good condition, and since the battery was disconnected for an extended period of time it is likely the PCM re-booted and the idle setiings were lost. You will need to feather the gas pedal to get it to start and idle until the PCM gathers enough data to idle by itself.

Tim_MN said:

1997 has OBD-II diagnostics, you should use them. Generic two digit OBD-I trouble codes are not very specific and basically useless.

Naturally you need a fully charged battery, in good condition, and since the battery was disconnected for an extended period of time it is likely the PCM re-booted and the idle setiings were lost. You will need to feather the gas pedal to get it to start and idle until the PCM gathers enough data to idle by itself.

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Normally I would use a scanner but I lost mine years ago and the Jeep won't start to drive it to where I can get it read for free.

I didn't even think about that where you have to manually idle the Jeep. I have had to do that many many times after a dead battery. My throttle cable broke in the process of the engine swap. It was rusted and broke being twisted around out of the way. I work at a dealer so my new one should be coming in today.

Ok I have checked for spark and I have it. Fuel is getting to the fuel rail. The gas in the tank is 7 months old. Can gas go bad in 7 months?