Quick question for you guys. Looking at a 1999 Baja with 256 hours showing and 158 actual. Previous owner claims the key was left on for 98 hours!! Can the engines be hooked up to a computer to tell true engine hours? Wouldn't the low oil pressure alarms go off with the key left on? Engines are 502 MPI's

hook to computer. Will read the hours off the ECU's.

No reason to believe the previous owner.

I agree with Mike check the ECU, but keep in mind that the ECU can be changed or reflashed which means that you cannot completly rely on that either. Use the hours as a guide and do a comp/leak down test and then make a decision.

Absolutely. With the scanner you can read hours off the ECU. What the owner says can be true. I did it once in my single 288 for five days (Sun-Fri) and added an extra 120 hours to the meter. Then again he could be BS'ing. But yes do the scan.

See what that last beer did to ya?

If MPI engines, definitely check with the scan tool. Even if the hour meters were correct, the scan should be relatively close to the numbers. You won't get all sync perfectly. The odds of ECU's being reflashed are slim, but it is possible.

Assuming they are all stock 502 MPI's, not really a reason to have messed with the ECU's. I would tend to think they show the actual hrs.

Did he offer the info on the hr descrepency on his own?

Broker boat at a dealership. The dealership had it listed it that way and that was their story. I know it's been awhile since I've been around the boat (long winter) but doesn't the alarms sound if the keys are left on letting you know low oil pressure?

I'm fighting that right now trying to get the alarms working right last couple of days.
Mine do not sound if I just turn the key on. Just the 3 short self-test blast. From looking at the wiring diagram, the warning buzzer sytem appears to be tied into the computer at the engine. So I'm am leaning towards the motor has to have been at least running for a couple of second to build oil pressure, then it will activate the warning system. Other wise it is disabled to keep the buzzer for sounding constantly when the key is just turned to the on position w/o actually having started the motor.
Just my thoughts, but everything is pointing that direction.

mine only sound a short while if the key is left on. then silence.
i have 93 502 efi's