I recently bought an Auto Xray XP240 scanner. I calibrated it for my car which is a '91 Z28 with the L98 motor (originally). I entered the 8th digit as "8" and then it asked for the 4th digit which is an "F". After that it goes back and says 5.0 Liter: Yes/No. I check "NO". First off, why would it ask me this if I already put "8" as the 8th digit?? Anyways, I go to scan and it gives me "SCAN ERROR" I tried numerous times configuring it and kept getting the same result. Just for kicks I answered "Yes" to the question of if it was a 5.0 liter. I went to scan and it worked!!! Why would it be doing this? I'm not sure if I'm getting proper readings since it thinks it's a 5.0 liter.

 

I've had the x-ray do the same thing to me, try entering a year model up (or down) this may solve your problem. It seems that gm used leftovers from a model year or if they ran short on parts at the end of a model year would start using the next production run parts without telling anyone. Hope this solves your problem, if not I would suggest contacting tech support for the x-ray.

 

I have the XP240, and use 1990 8 & F input codes. It works okay, and does not ask for engine size.
I agree with NY_REBEL, call them, for I have used the tech support line for other questions, and have found them to be very helpful.

 

I found tech support to be less than helpful. My x-ray works very rarely in my GTA and IROC. It works perfectly in every other GM vehicle I've tried, but it hates 165 ECMs. I called them, and they said remove the batteries and hold the power button down to get rid of static electricity. Yeah, I only have static electricity with 165 ECMs