ok im new and was hopeing ya'll might be able to help me.

got a 96 formula. just got the motor back from stroke to 383. before it went in it would pull to 62-6300 rpm no problem. now that the new motor is broken i have been playing around with it the engine stuters at 5200. some times it will pull through it sometime it wont go any higher and just falls of. i got a lt4 intake, heads and ecm so i know it has the lt4 KM i checked. opti is same one off the original motor with 55000 on it.

Can anyone help?

 

That sounds like an opti problem, it's always a good idea to change them out when you pull the motor apart cause the water pump is right over it and tends to leak fluid on them when pulled.

 

i checked the spark today and everything seemed fine does the optic in the unit help send signal for advancing the timing or just for basic timing?

 

can't really help you there however just because you're getting spark doesn't mean that it's bad. I would really doubt that it's a timing problem with the way you describe it, if it was timing the motor would still pull through. I take it you had the car properly tuned correct?

 

Valve spring??

 

the tuning has not been done yet i wanted the car to be broke in before i get it done the only programing is the hypertec crap form before the build. and the spring im not sure what is an easy way to check them.

 

Ask the person who did the heads.

 

to check the springs you have to pull the valve covers. Try taking off the hypertec tuning and see what happens, those tunes usually add timing and you may be getting false knock from that. What kind of compression does the motor have?

 

its running almost dead on at 10.6:1 i just read another question about this same problem from another user his problem was the ignition module what do u think?

 

ok i tried the icm replacement to no avale. opti i think is next. i called the shop that did the heads they said they replace everything with the package i paid for. i just hate to do the opti if its not the problem, its so expensive. but unless anyone can think of anything else let me know.

 

What injectors are in it? What cam are you using?

If you are running a stroker 383 with a bigger cam and injectors on a basically stock tune, I would expect it to run like crap. Get it tunned.

 

boy this prob sounds real familiar ...i'm having the same prob with my new 383......we replaced the opti in it with a autozone one which was a mistake in the first place i guess...and now pulling that and putting a unit from summit in it...we had my car out on the roads hooked to a scanmaster monitering a whole bunch of things and detirmaned it was the opti indeed or so we think so the new opti will be goin in tomorrow so lets hope thats it and lets see where you get on yours...my car just stutters and stumbles from about 5500 on up till i shift at wot

 

i replaced everything but the opti now going to do that next week. i hope it solves the problem.

 

ok i have now spent to much on this stuff. still got the problem. i have been reading a million post on this same lt1 problem. this is were i am tonight i am going to check for arching again. this seems to be a concensis. one way or another. i have replaced everything to no avale. so i will check this and see what i am getting. im going to do it at night so i can see better. i have seen this problem on my car before but didnt think these problems were realated but we will see.

 

have you tested your fuel pressure??