Bat Man

Last year it was having hiccups around 5k rpms. Like it would stop accelerating, so much that you would actually move forward (Like slamming on the brakes).

Mr. Mojo helped me a little and I fooled around with it, it went away for the most part.

Now its back, only this time its happening at 4.5k or 4k. Also Alotta carbon is building up in the exhaust pipes (I have brand new chrome tips so I notice this).

BTW: The car won't hiccup while in neutral and reving the engine, it will only hiccup will accelerating on the road. Really weird.

Bat Man

noone had similar experience?

ndC4spd

A friend of mine has a similar problem in third gear at around 4-5000 rpms..(its a 1993 corvette). He indicated that it feels like it hits the rev. limiter and "hiccups" like you have explained. He has been told to check his spark plugs and wires by several people.

Any one have any other thoughts? :confused:

bizaro

Bad optispark.
:iagree:
Same situation here. Changed opti= all gone. Might as well change the water pump while you're in there as well. :cheers:

Strick

Hey Marty,

How many miles on your current opti? If it's close to 50k and it is not vented, standby for more problems to follow. If you do the opti upgrade (venting) be sure to replace your wires, plugs and your water pump. :yesnod:

:flag :flag :flag

Mr Mojo

I'm currently having the exact same problem on my '93.

It only misses under load. I'm working on a solution, I'll kepp you posted.

Bat Man

I'm not too sure, I bought it with 86k miles on it, from a dealer. Don't know when the opti was last replaced, so I think its time to change it anyways.

Mojo, thanks a bundle. What do you think is causing it? When it gets stressed under load, does it kinda slam you forward like you hit the brakes?
Mine is that violent.

kawboy5792

mine does the same thing at lower RPM's when you put the pedal down and it loads the engine....like 6th gear at 1500 and you put your foot down, and it jolts.

Mr Mojo

Mine isn't that violent, it's more like hitting the rev limiter, but at 4000 rpm I know I'm not even close to that.

JACKSBLK94

i have the same problem as you guys! very frustrating! it a 94 and from a cold start the car idles fine then as it gets warm the stuttering starts to occur intermitently under load. and the idle stutters and raises iratically. i'm thing its the opti, but would love some like views before i replace it...the car has 66k on it.

LT4Sam

I had a problem a while back that I think I solved with a new opti (only fixed it on Tuesday and haven't driven much since) The car started missing a lot during light load (like passing on the freeway or getting on the freeway) but it idled and ran okay.

Long story short, Phil at Dynotech said it sounded like I had carbon tracking which is a situation where there is some arcing going on in the cap but will only be an issue when under load, it can vary case by case. Electricity will always follow the path of least resistance so it made sense that if the arcing wasn't too bad the spark would fire to the plug under light load, but arc when stressed to do so. Confirm it's not the plugs and wires, and if possible drive it with a scanner to see if you're getting random misfires in all cyls. If it is the Opti, have a blast replacing it.

Sam


[Modified by LT4Sam, 8:49 PM 4/20/2003]

Atok

I've got a '95 with 38k miles and am experiencing a similar problem. The car runs well under about 50% throttle. My problem happens at all RPM, in all gears (6-speed) but only under heavy load. In neutral it revs just fine. I thought my problem was fuel pressure but the symptoms you all describe above is very similar to what I see. Maybe it is ignition related? I haven't really looked into the problem yet. When I get the car on the road again I'll do more tests.

Strick

Gee, after reading all these simular problems with our LT-1s, someone should come up with a better opti-spark system. Venting helps, but how about a redesign of the distributor set up? I don't know much about the LS-1, but how did they work their distributor system? There has to be a better way. :rant:

:flag :flag :flag

kawboy5792

mine does the erratic idle too :confused:

C4

Mine just kept popping upon deccerlation, like I had a loose head bolt. I played with a few things and just thought, well its time. With the optispark, someone has indicated that it is not if, but when you have to change the unit.
While there, also encourage changing out waterpump and doing plug wires. I updated the new one with the instructions somebody sent me,\. Basically, you create channels for water to exit the unit, both inside and from the cover which fits over the rotor. The instructions were abit confusing, so, I just tore apart the old one to see how the damn was built and to make sure I didn't drill, solder iron to deep into the cover for the relief valve. Its really pretty cool. The hardest part is to enlargee the three holes and install a new drain hole and tubeing, expecially, even afterr you get it from Jeff Kopp for a good price, thinking If I screw this up I'm out $375 and gotta do it again....-C4- :flag

John Row

Sounds exactly like mine before I changed the opti. Spent 2 months checking everything else. Finally bit the bullet and did the opti. Been purring like a kitten (a rather beastly one) ever since.

John Row

Dyno Tech has developed an after market opti replacement. Sounds like they hit the issues. It costs about double the stock one. Biggest problem is that noone will know if it's any better for 80K-100K miles.

SPD DMN

Just put a new one in mine but it only solved part of my problems. My ignition module is failing as well when it gets warmed up. Got one on order, but I have already tested it with the coil pack off the '93 sitting in the garage. :thumbs: It is nice to have a "donor car" every now and then. Wife is never too pleased about it though. :D

Bat Man

anyone know where to get the dynotech opti?:

LT4Sam

http://www.dynotech-eng.com/dynaspark.htm