asudecat

iTrader: (11)

brand new motor. Has some dyno time and I drove it about 80 miles up until last night.
First pass out at the 1/8 mile track in Denton.
I launched and hit 2nd gear and as I was about to put it in 3rd it went pop 4-5 times kinda like a nitrous back fire or something, but I dont have nitrous. It pretty much died after that and I shut it down and coasted.
It will now no longer start. It's turning over but will not start. It will back fire out the intake every now and then when i try to start it.
There was a mechanic out there looking at it and he thinks it could possibly be the opti??
Sound right to you guys?
I had to leave it out there over night until I figure out what im going to do.

camaro-94-z28

iTrader: (3)

it seems 80 miles is a short break in period for someone to go to the track. (could be wrong dont really know) but i would be praying that it is the opti

asudecat

iTrader: (11)

It was broke in on the dyno.
Yes im praying that it is only the opti.

IllusionalTA

iTrader: (9)

popping out the intake does sound ignition related

BattleShip

From your description could be many things. Check the basics, fuel pressure and spark. I think if you own an LT1 you should have a cable to collect data it eliminates the what could it be, and gets you to this is what the car thinks it has.

If the fuel pressure regulator took a crap it could act like you are describing. Pops are never good and often are from lean mixture as well as ignition ie spark advance

Sorry to hear about the problems, but so far it doesn't sound that bad. Also there seems to be two schools of thought on breaking in an engine, baby them or drive them like you will. Personally I start the engine run a few minutes (no roller cams do not need a hi rpm breakin) check the engine for leaks and proper valve adjust etc, then give it what I built it for. If ithe engine has a problem why wait x miles to find it, I have never had an engine fix itself. But do what feels right to you.

Good luck and keep us posted

BattleShip

PS IF the fuel pressure regulator is bad buy an adjustable regulator. They are cheaper and allow some variation of fuel pressure. I don't change to variable until they fail, but they are nice to tweak injector size to what you need.

Also I assume you changed the fuel filter when you changed motor if not do it now.

asudecat

iTrader: (11)

by reading other posts, it seems the opti may have take a big dump.
The car had 85,000 or so when I did the big re-build. I only did a MSD cap & rotor replacement. Should have done the whole thing.

asudecat

iTrader: (11)

yes I have an afr, also new filter.

BattleShip

NO I don't think you should have changed the opti if there weren't signs of problems (ie debri in opti)

I have gotten rebuilt optis that were bad. Why go through the change and have a 20 - 30 % chance of failure I replace once they fail.

BattleShip

Still check that the fuel pressure is in range. All parts can fail check the basics it might be opti but eliminate other things first since it is nearly impossible to be sure it is opti. Then when you change it you will know it will run and if it doesn't the reuilt opti is bad. I ALWAYS start with the new opti BEFORE putting it all back together!

Trust me I have been there easier to fix everything then when it starts you know ALL is well

BattleShip

Another common problem with LT1s is grounds. The grounds all meet at the drivers front of head when an engine is worked on it is easy to break a ground wire.

I would definately check them I have actually had a few cars pickup at track with simply 'correcting' grounds. The reason is the electronics in the sensors and ECM require stable voltage to work properly when it varies their performance changes.

Like I said it is one of those small free changes that can help get more of what you have in your motor. Also in your case could be the reason it is sitting dead. If the wrong ground got disconnected you would lose your spark

Good luck

asudecat

iTrader: (11)

I will def check these when i get out there.
also going to diagnose the Opti using this stick from camaroz28.com

http://www.camaroz28.com/forums/showthread.php?t=601565

BattleShip

I will have to read it close this afternoon. I have actually used an Ocilliscope to find bad ones, and actually had a couple that dropped occassional hi/low signals.

From my quick scan of writeup I think the procedure will find the boken wire I mentioned. I think that your problem is more likely a bad ground than a dead opti (I hope for your sake). Most I had fail, operated well enough to start engine just ran like crap.

Mine have all worked eough not to set code but run like a turd.

Good luck let us know how it goes

BattleShip

Did you use locktite on the screws holding the rotor? The rotors will fall off if the screws weren't held in place with locktite.

If the opti procedure passes check that spark gets to a plug if rotor is off it won't spark

jasonisdn

iTrader: (1)

I am willing to bet it's the opti.

Speedy

Ha ha. Good call. If he isn't getting spark this is a definite possibility.

96capricemgr

iTrader: (1)

Adjustable regulators are MORE expensive and less reliable than stock. The ovetrwhelming majority of guys using them missuse them. Probably not your problem though.

asudecat

iTrader: (11)

I really appreciate all the good stuff you guys are giving me.
The ground problem is possible.
A few hours before I got on it just cruising and I threw a belt. But long story short we had problems with the harmonic balancer lining up and it was wearing the belt. and it was the belt that i had from prob 7 years ago. and it sat for 2 years while the car was being re-built.
So i would say it's possible that the belt got wild in there and could have knocked around some wire or something.
Who know's, but im going out right now to check all these things and see.
I'll keep you guy's updated
thanks

BattleShip

The last time I bought one at O Reillys I thought they were cheaper, on second thought maybe they are a few bucks more glad you corrected that. As for reliability none will match the OEM, and I agree most don't have a reason to have it. They are also the same people that will change to larger injectors with no need. I look at the signatures and chuckle what most believe makes a rats *** of a difference.

Can't change the world so best to roll along and laugh

95maroz28

iTrader: (21)

had an issue with my grounds at front of the head as well...cutting out and sometimes die. thought opti was taking a dump but traced it down to the grounds and now all is well