Hey guys, my friend has an lt1 and 4l60e combo in his camaro, it has a miss to it, not super bad but bad enough. when he cruises at half throttle or less it runs fine and pulls fine but when he floors it it doesnt want to run over 4k and starts banging out bad. would whatsever causing the miss be the problem? he was told the cap and rotor are really old and bad. thx in advance guys.

 

It could be about anything spark, air, mechanical, or fuel related. Maybe even the tranny if only does it while driving around.

I'd start with checking simple and inexpensive things first - the plugs, plug wires, fuel pressure, map sensor connector, exhaust leaks. Take the Mass air flow sensor off and see how it runs without that (puts the car in speed density mode).

Also might be a good idea to replace these if they haven't been replaced in a while - fuel filter, plugs, o2 sensors.

 

Definitely check what Firebrat said to check first, but.....(I'm surprised Firebrat didn't mention this because he probably knows way more about this stuff than me)....

....I'd bet money it's the opti-spark, especially if it is the unvented earlier design. These are known for failing because of moisture and other damage caused by high voltage. Before replacing the optispark and just running that darn thing, I'd swap to an LTCC setup, which is the coils setup used in the LS1's and NorthStar Caddies. WAY better than just the opti-spark setup.

However, the crank position sensor portion of the optispark needs to work properly, even with the LTCC swap.

If you do the LTCC conversion (which I highly recommend), the rotor can be removed from the optispark (it is obsolete), plus high voltage will no longer pass through the optispark, therefore, extending its life by many years, PLUS, if the engine is built for it, the engine can rev up to 8,000 rpms, without worrying about ignition failures/shortcomings.

Here is what I would do: Get a coilpack/ignition module from a NorthStar Caddy at a junkyard for about $50.00. Then get the barebones LTCC kit from this site http://www.delteq.com/opti_pricing.htm (part no. 1032 0r 1033-depending on where you want to mount the coils).

Doing it this way, the cost of this conversion will cost about what a good aftermarket opti would cost you, and it will be WAY better.

It's all plug and play, and it is up at the top of the list of very worthwhile mods to do on LT1 engines.

 

oh ok thx guys, it has a tiny exhaust leak but like i said at half throttle it runs fine till it gets around 4k and breaks up. hes going to change the cap and rotor and wires and plugs first

 

Just be careful when putting it back together. Make sure the cap is totally flush and seals properly, so as to avoid shattering a rotor.

 

and make sure that the screws that hold the rotor on are tight as well to keep it from slinging off.

 

thx for the heads up guys, i'm gonna get this car off of my friend and do it myself

 

since its a 94 and has the unvented opti can I purchase a vented opti from like a 96-97 model and put it on with no problems?

 

you can't buy the complete opti, the '94s are splined into th cam, and the '95-'97 are pinned, not for sure about the '94 Impala SS opti since they were vented but not for sure if they were pinned or splined.

 

Pretty sure it was splined like all '94s with just a vented cap. People have done it, but then you still need to create the second air port, of which MSD fixed in their cap and rotor kit, of which you get everything to replace cap and rotor which sounds like you need, and you get the vented system, hoses, and everything to make your opti vented. Instructions are complete and really useful, you can look at them on their website ahead of time if you'd like to get an idea of what you're looking at.

 

oh ok kewl so best bet is to buy a stock opti with an msd cap and rotor kit? i've been hearing mixed emotions on the msd opti so i figured an oem one and the msd cap and rotor kit will work the best.

 

It should make no difference which aftermarket cap you get, once you switch to LTCC and trash the rotor for good.

Since no high voltage will be running through it after the LTCC installation, it should last a long time. All you'll be using from it is the crank position sensor function, so I wouldn't go too spendy on any aftermarket opti stuff.

That's my opinion, anyway.

 

oh ok, well i want to do the LTCC setup but I dont have a lot of money, I just want to get the car running good right now so thats why I want to do all the basic stuff first.

 

You can put a stock vented cap on a non vented opti but you have to modify the three vent holes on the bottom to except a vacuum hose and get the vacuum hose check valve and filter from GM if don't you will suck the cap into the rotor .
If you google search converting a non vented opti to a vented one you will find it.

 

Good luck with your car, bro. I'm starting the 3rd gen/LT1 wiring harness mating today. I'm doing it the easy way, though. I'm having Pocket from here do it all for me. I'm mailing him my LT1 harness and 3rd gen harness.

I hate wiring more than almost anything.