LT1-LT4 Modifications 1993-97 Gen II Small Block V8

7000rpm

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Old 08-28-2006, 07:15 PM
  #41  
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sorry I took so long to respond....but you might want to check your valve adjustment.......if that's not it... then as everybody stated before....?opti?
one more thing check your timing.....sounds like someone fucked up the tune(and yes brian makes mistakes too) with that comp. it'll detonate...with too much timing...(but that won't keep it from going past 5500....)
my guess is OPTIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIII!
Old 08-29-2006, 11:14 AM
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recently the opti spark went south on my car while racing a H/C ls1:

as I nailed the throttle it pulled good to 4500, missed one time, then pulled to 6k and wouldn't go any higher. (rev limiter is set at 6800) hit second gear and the car started missing about ever 1k to 1500 and started studdering the rev-limiter at 6k again. hit 3rd and the car died.

started the car back, run just fine till I leaned in to in in 5th gear and started stumbling again. I drove the car another 3 miles down the road and progressively got worse with less load (4th gear 1/2 throttle, then 1/4, etc..) then got so bad it died in 1st gear with any load... started back up moved another 100 yards and died, then progressively got harder and harder to start, then would just crank freely.

checked every ignition part (plugs, wires, coil, module, etc.) and noticed that nothing was firing, coil nor injector, plugged in a differeny opti (in my hand) and free spun it and the injectors started squirting, tach started climbing (just like the car was running).

needless to say, a new opti base (with the optical sensor, wheel and backing plate bolted to the front cover) was ordered, installed and drive like a brand new one.

I know everyones on your *** about the scape-goat opti-spark, but if you haven't ACTUALLY changed the optical sensor and wheel part. don't rule it out. if you have, good, that's one less thing you have to buy.
then I'd move on to the spring pressure those springs actually have. could be some sort of valve float issue; back when my car was an auto,it done something similar, would hit 5500, pause, then go to 5800 and shift, then the motor would not physically "pull" past 6200 in gear (valve flat was so bad, the motor didn't have enough power to pull to the shift point) went from ls6 springs to comp 918's and never looked back.
Old 10-06-2006, 06:38 PM
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T.T.T.

Ok.still have this problem,Got a new opti like everyone sayd was the problem and.....

STILL THE SAME

Description:
From 4000-7000rpm tha engine spins very slowly close to 7000rpm,from 4000-7000 the engines pops,very little and silent pops

Anyone care to make a suggestion,Tune is fine.All new parts opti,Coil,Sparkplugs,Wires ect.
Old 10-06-2006, 06:58 PM
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Originally Posted by LT1MAN
when optis go bad, they go real bad, they dont just pop at the same rpm every time.
as i was reading this, i was thinking the exact same thing. the optispark is either BAD, or good. there is no SOMETIMES or PARTIALLY BAD at high RPM's. i doubt it is the opti.
Old 10-06-2006, 07:00 PM
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Originally Posted by Ari G
Ok.still have this problem,Got a new opti like everyone sayd was the problem and.....

STILL THE SAME
proof. lol
Old 10-06-2006, 08:32 PM
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you might want to check your valve adjustment......as I stated above......
Old 10-06-2006, 09:01 PM
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have you tested the fuel pressure yet? Still running the factory pump?
Old 10-07-2006, 08:13 AM
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255l walbro new,new fuel filter and 43 psi fuel pressure
Old 10-07-2006, 08:39 AM
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You might have hurt something in the motor. Drain the oil and check for metal. Pull both valve covers and look for anything that doesn't look right (broken valve spring, loose rocker, worn cam lobe, etc.). At least if you don't find anything you will have piece of mind.


Good Luck,


Daren
Old 10-07-2006, 12:15 PM
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Ok so you got a new opti - so thats not the problem

New plugs, wires, coil - what kind of wires are you running, are they taylor universal over the valve cover wires by chance? if so are you positive that you put the opti spark boots on the wires completely and correct? When I first got those wires I thought I put them together correctly but was wrong, which caused a high rpm breakup. They were a pain in the *** to cut and put together.

What kind of tune do you have, you said you thought that wasnt it but just curious?

My last guess is spring/valvetrain related problem.

I have ported stockers that flowed 290cfm@.600 with a cc306 and 1.6 rrs and I shift at 6800 so you should be able to make power up there easily. I have a dynaspark though and I'm still on stock intake manifold and tb.
Old 10-07-2006, 02:01 PM
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MSD 8,5 SuperCond.,chacked the wires,Adjusted the valves,still the same

nothing wrong with the internals,drained the oil 2 days ago,just normal
Old 10-07-2006, 02:04 PM
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PCMforless tuned the car,had it double checked by Madz28,itīs just fine
Old 10-07-2006, 07:09 PM
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Hard to say with out logg's and seeing it in person.

i can tell you it should pull to 7,000 no problem. Mine did with K-Motion springs and GM847 cam. as a matter of fact even at 6,900 power never peaked on stock heads. Once I put the LE heads on the Stock short block I picked up 50RWHP and it would peak at 6,800 like it should have. Gotta get that air in and out to make it all come together.

What are you O2s looking like?
Old 10-07-2006, 09:15 PM
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Got a datalog now,Shiiiiii.... Looks like ****

i can send it to anyone to take a peak,itīs datalogged with Turnerpro Rt, .bin
Old 10-09-2006, 09:44 AM
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http://quick.dropfiles.net/194943

This is the log i used LT1_92-93.ads and DA3.xdf

I use Tunerpro Rt 4,14



Quick Reply: 7000rpm



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