Mysticsvt96

I have a 383ci 96 corvette lt4 that i picked up from a guy recently. It was misfiring a bit and i have now replaced the entire ignition system to no avail.
(New opti (4 of them) some worked 1 didnt new wires (accel superstock)new plugs (autolite) new icm (bwd)new coil(bwd) new 02 sensors (denso) new maf (cordone i think) new map (bwd) recent valve adjustment new opti harness. I just dont get it. Yes i did use the cheaper optisparks. $149 new from advance and 1 from autozone ($153) car has good compression and good leakdown. Im experiencing misfires at less than 10% throttle or anything over about 4500rpm and its intermittent. Under %10 is always there but over is hit or miss. I dont know where else to look. No wires are touching the headers and nothing is arcing. Any help would be appreciated guys.

97REaper

iTrader: (11)

Use a Ac delco/delphi optispark

bufmatmuslepants

iTrader: (3)

^^^^^^ AC Delco or MSD

CamOnlyJabroni

Don't cheap out on one of the most important and critical things that effects how a LT1 runs. That damn thing can leave you stranded. Dont forget loctite and sealant for the housing.

ahritchie

iTrader: (1)

A stroked LT4 Corvette deserves better than a POS Chinese opti, does not surprise me at all you are getting duds from autozone, you have to pay to play when it comes to optisparks!

Shownomercy

iTrader: (1)

Did it ever run clean or has it always done this?

guppymech

iTrader: (7)

Do the Accel wires have a carbon impregnated fiberglass conductor or are they the spiral wound conductor type? The carbon fiberglass conductor type is very susceptible to failures from bending or pulling on the wires, basically junk. Hopefully you have the spiral wound variety.

Mysticsvt96

They are the super stock build it yourself wires. Unsure of which i have. I know they have similar to a spun wire in the center.
As for the optis i figure one of 4 would have made some kind of difference? 3 ran about the same ya know what problems im having now 1 barely ran at all.

ahritchie

iTrader: (1)

Shitty Chinese optisparks have shitty Chinese quality control and most either don't work, misfire sporadically, or don't work very long, there's no getting around their shittyness unfortunately unless you get lucky or enjoy dissecting and repairing poorly manufactured optisparks. There's a thread on here about taking them apart and inspecting the solders on the optical sensor if you want to try that...IMO take them back and have auto zone refund you 100%, I hope they go out of business selling shoddy optisparks to LT1 noobs LOL....that's what I ended up doing after trying 2 of them...

Mysticsvt96

Anyone know where i can find an oem nos one? Dont want a reman

ahritchie

iTrader: (1)

http://www.ebay.com/itm/BRAND-NEW-ACDELCO-OEM-LT1-OPTISPARK-DISTRIBUTOR-PART-1104032-IMPALA-SS-1994-1996/121605450320?_trksid=p2046732.c100040.m2060&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140107095009%26meid%3Db47f00a8eb094e9db2bc9e86e3f7ea67%26pid%3D100040%26rk%3D4%26rkt%3D4%26sd%3D230691061057

Mysticsvt96

Thank you sir.

seymourbuttz

Dont be surprised if you still have the problem with an OE opti, though it is still a good idea to get one. Even if you did get four bad ones from the parts store chances are low that they would yield the same problems you described for each one. If it had never ran good and it is a modded 383 i would check with whoever tuned it.

joelster

You just keep throwing new parts at it? Crazy.

joelster

Does it run better when you first fire it up (open loop)?

96capricemgr

iTrader: (1)

The question about did it ever run right is a VERY good one that could guide a lot more questions if answered.
Cheap wires built DIY style sounds BAD too.
joelster's question is good as well.
I wouldn't fixate on parts swapping, you have put a bunch of lower quality stuff on it but even a crappy chinese opti 1 in 4 is likely to have functioned decently.
What plugs?
Few build details?

Mysticsvt96

Actually yes it does run better in open loop. And i dont know if it ever did or didnt run any better i bought it this way thinking an opti would fix it.

Mysticsvt96

Build details are as follows
Eagle 4340 forged crank
Eagle esp 4340 h beams
Mahle forged pistons
Clevite h series bearings
Arp hardware
AFR #1039 cylinder heads(competition pack)
Ported matched lt4 intake
Bosch 44 lb hr injectors
Bbk power plus throttle body
17/8 longtubes
Comp 292 xfi-hr camshaft
Comp ultra gold roller rockers
Trick flow pushrods
Afr guide plates
Arp head bolts
Cometic head gaskets
New water pump

96capricemgr

iTrader: (1)

so it is a magazine build that never ran right, you have a serious uphill battle and need a knowledgeable local enthusiast to try to sort out.

If the springs are the standard AFR, they are not up to the task of that cam and you will find high rpm float to be a problem

Purple Poncho

iTrader: (1)

Wtf? Any build is more or less going to look like that. Magazine build....because it doesn't have a custom AI cam and AFR heads....when was the last time a magazine did an LT1 build anyways?