cowboyupo6

rebuilt motor was done professionally i put it back in the car and cant get it to start it keeps back firing through the intake... any sugestions?

jasonp31

Check the plug wire routing to make sure the wires weren't crossed.

Formula350

iTrader: (3)

Sounds exactly like timing being 180º off.

cowboyupo6

its a 95 so cant the dist. only go on one way.

Formula350

iTrader: (3)

The dist can only go in one way? I don't know much about how the change is after 94, but I thought they could still go in 1 of 2 ways. Right, or 180 off (wrong).

cowboyupo6

yeah it only goes on that one way though ive taken it off thinking it was 180 out... im clueless

Formula350

iTrader: (3)

I would then make sure the rotor and cap is good. But first I would buy a new ICM and Coil. Just get a stock AC Delco coil and ICM from GM, or in the Delco packaging. If you have an Accel Distributor, then that's your problem lol I guess everyone has issues with them, either immediately or close thereafter.

cowboyupo6

yeah well the car ran before i swapped motors im using all the same ignition parts too thats why is so weird just different motor...

Hugger-96-lt1

iTrader: (8)

My friends z had the same thing happen and the timing was off.

Formula350

iTrader: (3)

Parts sit, and can go bad when then re-used. That's why all junk yard parts, when gone in might be good, but sold are not. Hence the usual 30 day warranty.

mtsumedi

There's a 2 month old Dynaspark optispark sitting in a junk yard somewhere out there from when I totaled by 1992 Vette.

cowboyupo6

yeah well i got spark i just went and double checked everything... i do have a cc 306 cam now and it hasnt been tuned yet could that effect it not starting... i hear the compression coming back through the intake.

Formula350

iTrader: (3)

Mis-adjusted valves (rockers) then would be my next guess.

cowboyupo6

oh ok so i would i go about checking that?

Formula350

iTrader: (3)

Compression check on each cylinder. It should be, since you have a new motor, like 210psi +/- 10psi, on each one. (Someone correct me on this please. It's an educated guess)

cowboyupo6

alright ill have to give that a shot...

GreatWhiteZ28

iTrader: (15)

Sounds like you got some mis-adjusted valves to me, mine did that after i did my cam swap, took me forever to figure it out, just went down the list of possibilitys

cowboyupo6

yea i honestly have no clue everything was done by a machine shop that has a good repatation and i've seen several motors that they have built in some bad @$$ cars.

Formula350

iTrader: (3)

So no compression test yet I assume?

cowboyupo6

no havent had time been working... i did pull one of my plugs out though to smell for fuel and they look fouled out and their brand new?