1998 Comtour engine timing changes
 

I have a 1998 Contour, 4-cyl. I've replaced the timing belt twice. I know how to set the timing by TDC using the engine block pin and sticking the screwdriver in the #1, lining up the cams, using the belt tensioner etc. Each time, the car starts. The problem is, when I put the serpentine belt back on, it won't start and the timing seems way off. I take the belt off, it starts and runs and shifts beautiful down the road. I've replaced the crankshaft, camshaft sensors and tensioner already. I know mechanics and I know what I'm doing, but this one I'm baffled.

Could you have a loose crank sensor reluctor on that crankshaft or maybe installed the wrong crankshaft?
Were you able to compare the replacement with the one removed? The slots on the reluctor are critical for proper engine operation.

The crankshaft wasn't replaced, only the timing belt. It runs fine down the road without the serpentine belt.

Did you check everything the serp belt turns for any kind of problem?

Are you positive you have the correct belt routing ?
Is the diagram available for you to use?

The serpentine belt is on good. I've played around with the timing I swear about a dozen times, tearing everything down and re-doing it. Each time I return the timing to the way it should be, the car starts right away, runs and shifts smooth. I've done it so many times, even a Ford mechanic could learn from me. So I'm pretty confident from what I've read and experienced, I know how to do it. I also did this around a year ago and it ran well with the serpentine belt on also. This time, I put the serpentine belt on, it won't start, take it off it starts fine. The serpentine belt has nothing to do with the timing end. This time I am really baffled.

I can't tell from your first post, but what if you have a problem with the crank pulley ?
I believe the crank sensor is operated at the flywheel end , did you have a chance to check that out? Whatever is happening is affected by the belt installation so you just have to take one step at a time and watch what changes when you install the serp belt.

The crank and cam sensors have both been replaced. If these things go, the engine wouldn't start at all. This is what confuses me.

The crank pully looks good and fits in the keyed slot.