Car spitting Sparks

[FstStig]

Hey Guys,

Just put another 5sfe motor into my sx celica. We changed over the timing belt and tensions etc as well. Thought it was all good to go today, drove off. I was behind my dad in his 4x4 (he was in the celica) and noticed Sparks coming out of the exhaust... After the sparks stopped a little bit of black smoke would follow. I know this is a commodore forum, but you guys seem to know more and i seem to get a better response on here then a Celica forum.

Thanks in advance.

Mumbo

[caaf]

Not sure however it does sound like a failing cat?

[FstStig]

I had a feeling it could be the Cat, as when the last motor blew about 4 - 5 lites of Coolant went through the exhaust. Could of the coolant stuffed it?
My dad also mentioned that was a little bit to much back pressure when going from 1st to 2nd.

[greenacc]

excess Back pressure matches the stuffed exhaust theory. That much water down the exhaust would surely soften and flake off any build up in your zorst, and cuase rust .. and any of these could cause sparks. Might go away after a while ?

[FstStig]

I replaced the Spark Plugs and that has seemed to help it abit. Its still back firing between 2nd and 3rd now, There was about 2 sparks when we drove it back home yesterday (about 60ks from my place) We replaced the timing belt so that could still be 1 tooth out.