Alright
1993 Corvette, LT1 Vortech v1 Supercharged. 6 spd
Details
PO says engine was rebuilt 35k ago. exact details are vague as its been through at least 3 owners before me, and three owners ago all of the major work went down.

When I got the car the crane ignition was dead and was bypassed to stock ignition, it ran pretty warm around 230 constantly and fell on its face.

Ive recently changed coolant ratio and added redline and temps came down, and haven't had the chance to replace the ignition box, but did install and MSD coil in place of the factory coil. This made a significant difference. The car was running awesome.

After giving it a kinda hard run the night before, and even stalled once when I was being soft on the clutch, the next morning the car cranked and cranked and wouldn't start.

Before it started literally after one crank, so this was very unusual. I became panicked and decided to give it some rest. Went inside cleared my head and thoughts, went back outside and tried again. Spent like 5 minutes trying to start, playing with the clutch a bit, playing with the throttle. It would try to start kinda stumble and die until finally, it started and I gave it a ton of gas and it stayed alive. A ton of smoke came out the back along with a strong smell of fuel. Eventually it mellowed out and I drove it around till it was warm. Eventually turned it off, and ran inside came back out, restarted fine. The car ran and felt normal and was easy to start when warm.

The following two days same thing happened.

After that, I drove it and parked it somewhere, it sat for a good long time, then tried starting it wouldn't catch, and the battery died. after trying to start it with a tow truck again, gave up and brought it home.

Today, I replaced the fuel pressure regulator as it seemed thats what seemed to be acting up. While the fuel rails were off but the injectors still in them, I put the ignition to on to see if fuel leaked out of anything, nothing came out.

I am of limited knowledge and learning everyday. My current plan is taking it to my auto class on Tuesday but I have work on Wednesday that requires a lot of driving. I will run the codes and do some tests and see what we can do.

Any help is appreciated.

I haven't hooked up a fuel pressure gauge yet but will on Tuesday

I think its either opti, injectors?, plugs fouled?

Thanks in advance guys.

 

Confirm you have ignition spark while cranking with a spark plug wire off.
Like for the #1 cylinder. Driver's side all the way forward towards the radiator.
Connect the spark plug wire to a spare spark plug and confirm that you have a Hot Blue spark.
A Yellow or Orange Spark means that there is weak ignition spark or high voltage with NO CURRENT Behind it.

HOT BLUE SPARK is what you want and need. High KV and Good Current(Milli amperage) present to properly ignite the air and gasoline inside of each of your engines cylinders.
Especially important on a Supercharged or turbocharged engine.

Check this and let me know what you see.

Brian

 

Got it, will do that after work tomorrow, idk how long the current plugs have been in there nor do i know what kind or brand they are. I already have new ones waiting to go in but I was waiting for a lab day in class where we need to change plugs (to birds one stone) should I pull the wire and use one of the new plugs? or pull the plug and wire and test it with the plug that the car is using? or does it even matter?

 

If you have a weak ignition spark present,
likely all 8 spark plugs are fouled out.

Supercharged engines need a rich AFR at WOT.
If they run lean for too long you can kiss your top piston ring seal goodbye.

The high heat generated with a lean AFR at WOT will super heat the Top Ring and burn the plasma moly(moledium metal) off.
Then score the engine blocks cylinder walls very bad.

Tool steel Piston rings sets are best with high boost HP applications(22-40+psi) but are very expensive.

Brian

 

Im running 6 PSI, I dont know the condition of them, but will take a look tomorrow, I dont think its running lean, but I am on stock injectors, and I am pretty sure I have an FMU.

In the future I plan on getting new 63 lb injectors, ditching the FMU and getting a new eprom along with the new ignition and data logging stuff to tune it all up, but for now I just want my car to run.

So will it matter if I test the spark plug that's in the car or can I use a new one?

 

There are many other forum members better than I am with C4 hardware and software computers and tuning for Suercharged application on your Vette.

MSeven is very good.
ddahlgren is excellent.
Many others here too.

Let them help with your tune.

I know engine mechanicals best, 700R4 transmissions, rear differentials,
And I am a performance ignition expert.
Vertex Magneto's especially.

Wide band AFR gauges today don't lie whats going inside of a running engine.

I own and use an AEM Wide Band AFR gauge.
According to Dave, reading in Lamba is best.
On my list to buy this year........

Lamba reading wideband AFR gauge.

Brian

 

Don't buy thin platinum wire tipped spark plugs for your blown Vette.

You don't want them.
The thin platinum wire tip will glow cherry red when you are at WOT with Boost.
That will cause pre-igniton to take place and possibly lead to detonation too.
Broken shotblock parts then.

Buy Racing NGK's, Accel's, Autolite's, or Champion's.
Just the standard Copper core spark plugs with a Nickel metal protruding electrode tip.

Trust me that style is safest to use in a blown application and will give best results when tuning and racing your Vette @ WOT.

Brian

 

I've got Ngk tr7ix waiting to go in, I've also got a wideband sensor on the list, and a 4 wire one instead of what we have.

But still wondering if I should use the plug that's in the engine for the test, or can I just use one of my new plugs.

 

Use a brand new spark plug for your Visual Hot Blue Spark ignition test present or not.

Brian

 

Hi,
I am the tech manager at Autolite and a shop owner that works on alot of C4's. One word-OPTISPARK! Your has what I call "morning sickness". Those units have a real issue with moisture intrusion that can and will cause the symtom you are having. There are vented units from GM (even a GM TSB about them) and very nice aftermarket units that eliminate the problem. that said, they can be a real bitch to install. Email me at Jay.Buckley@Honeywell.com if you want detailed installation instructions

 

Yea, after talking to a bunch of people the optispark seems to be the cause.

Since I got the car, I felt the whole optispark fail thing was overhyped and felt that I probably wouldn't have a problem with it, but it seems I was wrong.

I really hope it is the optispark though, I cant just through money at this thing.

Any recommendation on best bang for the buck unit?
Was looking at MSD unit and it comes with the stuff to vent it and control of a some timing, but what do you guys think?