If the timing chain skipped a tooth or two what would the effect be??

I am trying to time my 2.8 and the timing mark is showing to be at, or a little AFTER TDC. When I try to advance the timing to 10 BTDC the engine runs rough and extremely rich. When trying to restart, it is extremely hard to crank.

How do I determine if the chain has slipped a tooth or two?

I noticed by your post that you are trying to set the timing to the timing mark. Only one problem with this, on our Fieros, I've seen instances of the outer ring of the Harmonic Balancer rotate and throw the timing mark out of whack. If you can bar the engine over (don't forget to remove the coil wire so it doesn't fire up on you) while someone is watching the rotor and find out how much slop is in the chain (the bottom end of the motor rotates until the slop is taken up in the chain then causing the rotor in the distributor to turn). If there's a lot of slop in the chain, then it is pretty likely that it jumped a tooth, otherwise, you may be trying to set the timing to a timing mark that has shifted. If the mark has shifted, tune the timing by ear rather than by a mark. If it hasn't shifted, the chain and gears will have to be replaced.

------------------
As Alice Cooper once said...

quote Feed My.... Frankenstein!

Thanks for the tip. I hand turned the crank and watched the distributor. My gears/chain must be in pretty bad shape. The crank moved about 25 deg before the rotor moved. No wonder I'm having all sorts of trouble! I just installed this long block about a year ago. I guess I know what I'll be doing the next few days.

If your chain skipped, it won't run. If it is really loose, your timing will jump around a bit.

You are putting the ECM in diagnostic mode (jumper between A nd B terminals on ALDL connector) when you time it, right?

------------------
"Its a Fiero thing... Heck, even I don't understand!"

Timothy E. Smith
1986 SE V6
1985 GT (parts car)
1984 Coupe
1996 Ford Probe GT
1999 Chevrolet Silverado Z71
1975 Chevrolet ElCamino SS

From my experience the car will run if the timing jumps one or two teeth. At lower RPM ( < 3000) it will run rough, miss, have little power. If you floor it, you will feel that the eng starts breathing better in the mid to upper RPMs but returns to rough when you slow down. As you mentioned it is hard to start. This behavior was experienced on GM, Ford and Chrysler cars in the 70s and early 80s. You mentioned that you have 25 crank degrees of slop and if that is the case, you probably shouldn't drive it much more as you might destroy the timing housing. GL