Just finished the rebuild, fresh bottom end, heads, LT4 cam kit...
About 20 miles on it, was running really good, no codes or SES. I get on the freeway, its running fine at around 3K rpm. Car dies and will not start. It cranks over, and backfires out the exhaust. No codes stored. Car has fuel and spark.

Any ideas?

 

Have you checked to see if you're getting a spark from the opti to the plugs, and from the coil to the opti? If you did anything to the fuel system check your electrical connections there as well.

 

There is spark coming out of the coil, and out of the plug wires.

I double checked all the injectors, all plugs are getting 12v, and they all read between 12.1 and 12.6 ohms resistance.

 

Going to test the optispark when I get home......

 

well when this happened to me on my 93 z28 the bolts on the cam gear broke, and the engine was mostly stock and never apart. No idea how it happened but i couldnt figure it out so pulled the valve cover and nothing was moving Then i found out it was an interference motor and had to pull the heads and replace all the bent valves? May not be whatyou want to hear but that was my experience

 

My friend's TA had spark at the wires but it turned out not to be a "hot" spark. Buy a spark gap tester and verify that the spark can jump across the proper gap (it's something like 3/4"). We replaced his coil and the problem was solved.

 

That has a chilling ressemblance to what happened to me. I just got on the highway at 3,000 rpm, only driven 10 previous miles after heads/cam. Car shuts off, would turn over but wouldnt start. Next day it started up running rough. Then found a hole in the pan, I threw a rod. But you just rebuilt yours so I wouldn't worry too much it could be alot of things.

 

Did ya check your drive pin length? Maybe your rotor has come appart like they all do.

 

I'm on duty so I wont be home for a few days....BUT

I just realised that the timing chain I used (Cloyes hex-a-just billet double roller), is the wrong one. When I installed it, it the bushing stopped the pin from sliding as far into the opti as I thought it should go. I thought it would still be fine though. I guess not.

While I dont yet have the cover/opti off, my guess is that the pin jumped out and is turning the opti from the wrong spot.

I'll update this thread on wednesday when I pull it apart, thanks for the responses, hopefully I did not kill the $$$ Opti.

 

Nope the Hex-A-Adjust won't work.

 

Shouldnt you be getting more than 12v's at the plugs? isnt the job of the coil to increase the spark?

 

Wrong plugs, I measured 12V at the INJECTOR harness plugs.

 

ahh i see i was wondering why anyone would want to try to measure about 25k volts but i see i am wrong forgive me, did you ever get that deal straightend out with that guy. Its 1BADLT1 from the other board.

 

Nope, nothing yet. Can't say I really expect anything