I just saved a 1990 240 wagon from the crusher, seems to be in great shape. When I dropped a new battery in, the ignition fires up the engine but it won't stay running for more than 1 second. Spark plugs look new.

Then I checked the oil because that's about the extent of my expertise. It was new and not burnt. Sticker says it had an oil change a couple months ago, and I know at that time it was drivable (that's how it was parked there).

The junkyard guy says he thought it was a computer issue or a gunky exhaust.

One more thing: in the trunk there is a funky-looking hard plastic tube that looks like the head of a vacuum cleaner: one end has a round opening about 4 in diameter and then it curves 90 degrees and the other end has a flattened opening.

Oh, and I found a big white square relay in the glove box. I think it's for the fuel pump. Not sure if it's been yanked out or just a backup.

Where do I go from here?