i have searhced this forum and havent found an answer for my problem, so here it goes. i just did an engine swap. i took a 08 1500 engine and put in my 97 blazer. tried to start it and learned i was getting no spark. i took my ICM to the local parts store and it tested. its fine and so is my spare one. some info you should know: my blazer started and ran fine before the swap. i changed the engine due to a spun rod bearing. the new engine is a 4.3 vortec. same as my old, other then this engine is drive by wire and had no distributer. i put on a marine manifold and installed my old distributor. i used all my old sensors. i even had to drill and tap the back of the block for the knock sensor. the timing cover was different so i had to tweek it a little to get crankshaft sensor to set in deeper. i also had to install my old sprocket on the crank(for the crankshaft sensor to read). i made sure every thing is plugged in(i hope so) and all grounds are hooked up.

i cant think of anything else to do to it. any help is appreciated. thank you.

 

Did the cam have the distributor drive gear on it??? Have you verified that the distributor is turning?

 

Yes and yes. the distributorless ignition actually uses a bottom half of a dist to run the oil pump and to seal of the dist hole(atleast on the 4.3 anyways). iam not getting any signal going to my coil, thats why i thought it might of been my icm, but it checked out fine. then i thought possibly my MSD box. so i disconnected it and hooked it back up stock. still nothing. would any of my sensors cut off my ignition?

thank you for your responce.

 

Were the cranks machined the same at the front as far as alignment of the reluctor ring?

 

yes. my old ring slid right into place. i just had to line up the key on the crank and slot on the ring.the key location looked to be in the same location when at TDC. the ring on the new engine is bigger(this is why i had to modify the timing cover) and has a bunch of teeth with a spot of maybe two or three teeth flat, where as my ring is much smaller and has three cut outs. i ground down the timing cover so my crank sensor would sit the same distance as my old engine(.050). i looked in my chiltons and haynes manual but havent found any procedures on how to test my crank sensor. do you think this might be my problem?

thank you for your help.

 

It is quite possible if it is not picking up the proper crank signal (which is required for it to start) either from improper air gap or improper timing with the engine. Since you have mimicked the air gap from the old front cover, I would look at the alignment of the reluctor ring at TDC #1 and try to relate that back to the old crank. It may be something that you just have to have a new keyway groove cut into the ring at the proper alignment.

 

ok. i will check to make sure that its 100% aligned then i will post the results.

 

Also, did you make sure that the reluctor ring was put on in the proper direction. Here is some info:

 

iam sure i put it on the right way but i will double check that as well. iam thankfull that you said somethink about that because i wasnt 100% sure wich way it had to face, but can remember putting it on in that direction.

 

Will the old front cover bolt up to the newer block?