Okay i know the first thing you are all going to say is its the timing! yeah its that and something else. I can not time it with out it running. I dont have a cat-back connected to the y-pipe so the backfiring sounds like a howitzer w/ lots of sparks i suppose if a cat was there it wouldnt send sparks flyin. I havent done any datalogging yet cause i think it has to be running . My Dad was turnin the distributor and kept saying its getting plenty (meaning too much) of fuel, not likely that its getting to much.

I have the following mods, Port/polish TBI, rebuilt stock heads, new valve springs .500 max lift, 96 LT1 cam, short headers, and those waste of spark plug platinum +4's.

I'm affraid that if i continue to crank the engine with it backfiring like it is and knowing something isnt rite i could damage it internally.

I noticed that when i turned the key to the "ON" position the oil gauge "needle" moves to max pressure, but when i crank it - it drops back down to about 30 or so.

should i increase the PSI from the base of 10 to something higher? or am i just spinning my wheels.
Im not sure how old the coil is all i know is it came with engine and worked fine until i took it apart . I've heard bad things about those over priced plugs only after i bought them.

So anyone have any ideas as to what the heck is the problem?

 

I would say timing also. But I would check your firing order first. When I did my swap I messed up the spark plug wire order. Caused some nasty backfires, one was an open flame on the tbi. Take your dist cap off and take #1 spark plug out Then crank the motor over slowly until your thumb gets popped off the #1 plug hole in the block that will tell you tdc. Then look to see where the rotor is facing, It should be pointing forward and kinda towards the driver side. If its directly opposite then your on the 180* off. So crank it around until it popps your thumb off again. If it's facing forward this time you got tdc, now redo all your spark plug wires on the cap starting with #1 where the rotor is pointing. THen try advancing and retarding the dist while cranking.

Try that, if that doesnt work post again. We'll figure it out.

 

PROM?
plug wires (order, condition, etc)?
valve lash?

 

Lol, yeah, due to recent TBI trends, I'd take a close look at your valves...

 

I woul check the vavles and distrobutor and wire allignment. It is very easy to get those two goofed. Are you dissconnecting the ETS while you try to time it. If you don't you will be fighting against the computer.

 

loosen the distributor clamp, rotate the distributor alittle, try to start, rotate it some more, try to start, or you can have someone else crank your engine while you rotate the distributor. After i installed my intake manifold i installed the distributor 1 tooth off and it idled rough, keep dying and backfired. So i just move the distributor alittle, had my friend fire it up and continued to rotate it until it had a smooth idle, then set the timing.
Also check the valves and you have a **** load of mods on your car, i hope you arnt going to use the stock chip.

 

 

89fastlookinRS:
Okay before i took it apart i had the firing order on the cap rotated 180 degrees because it wouldnt start with it the way the chilton manuel said. I put that back to stock order. I will when i get back to it. bring it up to TDC and reset the position of the cap in relation to the nearest poll.

Token:
PROM- have burning software and burner. i havent approached that yet.
Plug wires brand new cap and rotor new, module is good.
Valve lash i took the rockers down to the pushrods until i could just barely turn them but yet i couldnt move them up or down.

90RS305:
You mean i have to take all of that crap off again to get to my covers, just so i can take em off?

ShiftyCapone:
I didnt think of disconnecting the EST at first-I realized it should be disconnected so i did that, it still backfired only it was louder and the flames were more evident.

vjo90RS8:
I have the stock chip in it for now i dont plan on driving it with that in there. I am hoping to at least get it to fire, rather it runs like $h!t or not i am not worried if i datalog with it running 1/2 assed that would be fine. I would love it if i could get it to start but then die thatd be fine w/ me. at least i could hear it run.

Valves it is, maybe they need the extra 1/2-3/4 turn?

Will try that tonite. when i get off work.

 

haahahaha yup

 

i would only go 1/2-3/4 turn after 0 lash, thats what i did when i installed my rockers. If you are going to readjust them then loosen them all up and start over, you dont want to just tighten them more because you might overtighten them and thats not good either

 

well so far valve adjustment is good they arent too tight but they arent loose.

 

What are you refering to when you say EST? I am having similar problem with my new motor.

 

EST Electronic Spark Timing. is a single wire on the passenger side disconnect it when setting base timing. otherwise youll be fighting the ECM. i think its a Tan wire with black stripe, you cant miss it as its sticking out of the main wiring harness inthe engine compartment.

 

I might add that those of you who told me it was my timing where once again rite. i switched the position of the rotor back to stock location @ TDC and it spudered for a second and fired rite up. Now its time to do some datalogging.