mrtravass

Hey guys, I have a custom installation where I put an lt1 into my '93 s10 p/u. I have had the engine in and out a couple times and the previous two times it would always fire right up after installation - this time is different. While cranking it backfires through the intake and will not start. It has good fuel pressure and good spark. I am going to double check my spark plug wires for the firing order, what else could cause this? Can the opti be installed incorrectly and screw up the timing? Thanks for any help

bad95z28

ABSOLUTELY.... it can screw things up for sure. i'd check the plug wires and opti first. if its backfiring out the intake then its probably major ignition/timing problems.

TrouserSnake

100 percent opti is on wrong. or plug wires are on wrong

mrtravass

Ok, how can I check the opti? I dread taking it back off because it is a pita, but I guess that is what I will most likely need to do. I have a shop manual so just follow the directions, or does anybody have any magic way to fix this? Thanks

smoknta

you will have to take it back off to check it.....it will actually only go in one way, unless it is forced on. The shaft that goes in the cam and the opti has sort of a key. It will only fit one way....i have heard of people just sticking it in and then sticking the opti on top of it and then using the bolts to pull it flush. Very bad idea. One, the timing might be way off and it will just chew the splines right off the shaft. Make sure when you install it the shaft snaps into place and the key is aligned properly. The opti should sit flush with the timing cover, before you ever attempt to put the bolts in. Do not force it on, or try to pull it flush with the bolts. Hope this helps.