Hi! First post here as… I owe 86 Corvette for few days. I got blown away when I realised it's like 4mln posts under C4 category only. I read some, but I couldn't solve my issue yet...

The story:

• 86 Corvette, 2 owners, original 24k miles. C4 before lifting was my childhood dream
• Car came from COPART, as flooded. Dirt on both tires shows water level (photo attached)
• Water level was confirmed when taking out carpets - it’s like 10 cm from the top of center panel (with gear lever).
• Car got flooded in September 2024, I got it a week ago
• Carpet underlayment was a bit wet, so I took out the seats & carpets
• 12V battery was obviously dead. After recharging it and testing in the shop the guy said 76% of heart. No need to preplace it at the moment. On the dash I see like 12,2V
• I have removed spark plugs, and inspected cylinder with USB camera - all I saw was carbon buildup on cylinder walls, no water.
• Engine oil level: between min and max - water didn’t get.
• Transmission oil level: way over max. My understanding is water got in through transmission vent.
• I have set of 3 keys. I’ve also cleaned pellet.
• I couldn’t lock/unlock the door with the key (both sides). I took off door panel and disconnected metal rod going to door actuator. I left actuator disconnected. I know it works fine (tested out of the car with another 12V battery).
• I’ve checked all the fuses (fusebox on passenger side) and 4 fuses behind information center (if that’s the right name).
• Power Antena doesn’t work. Radio works, but no sound out of the speakers. Interior light works fine

I read a lot on forums, watch many YT clips when waiting 12 weeks for the car I said to myself: It’s time to crank it! All I got was alarm sound, I believe I hear fuel pump for like 2-3 second.

Dirt on the tire marking water level





After some research I decided to bypass starter relay. After doing this, there was no alarm sound, but also no cranking. When pushing the ignition key all the way in I see SECURITY blinking. At the moment starter relay is not bypassed.

I have lifted the car a bit - to reach started with screwdriver - something spins. I cannot say if it was starter itself or bendix. Anyway it’s not completely dead.

Below clip includes: fuel pump noise?, alarm sound & blinking SECURITY.



I’ve heard some opinions: it could be third party alarm issue. There is a wire going from horn to the driver seat. Two photos are showing blue wire, and how it end’s. It wasn’t connected to anything under the seat. I didn’t check if maybe there is any box along the way of the cable.





I’m a bit puzzled:

1. Is it’s VATS issue?
2. Does it look like there is/was third party alarm?
3. Maybe I should check anything else.

I’m sorry for long post - I just wanted to list all I know

I count on your help…

I found an aftermarket alarm installed under the dashboard. Now, I need to restore the original wiring. The problem is, I can't find a socket for the pink-white and white 2-pin connector. What is it for? It seems to be routed into the main wiring harness leading behind the digital cluster and dic

Looks like the Pink / White plug is for you footwell light.

I didn't even realise there is one (on passenger side it's also dark). Mystery solved!.

There is another one: I got "clunk" but no crank. Cables are not loose at the battery.
Probably it's time to remove starter. Is it?

To me it sounds like the battery isn't strong enough to crank. sounds like the starter engaged though. What's the CCA of the battery in the car?

Just to be sure: I have used 2 month old battery I bought for another car - same result. NEXT STEP: to take out the starter and (probably) replace it with the new one....

Just a Question,

I know you scoped the cylinders with a camera, but did you also check to see if the engine is free and not seized?

My way of thinking:
1. No water in cylinders --> OK!
2. Perfect oil level --> OK!
3. Water level --> OK! (not allowing to get water into cylinders from the top).
With 3x OK! I belive it's all OK. I was wondering how could I check if engine is free... Could I put it jack and try to rotate back wheels while transmission is in drive? (it's automatic).

Your logic seems valid that the engine should be free, You could mark the serpentine belt with chalk and try cranking it multiple times and see if the belt has shifted at all (since it does sound like the starter is engaging)
I have a standard and my process was different for my restoration and the verification that my engine is free.

I'm going to follow you suggestion witch chalk tomorrow..
May I ask what's your process? How do you check it?

First I am not a mechanic but do have knowledge of cars.

With mine (its a standard)I jacked up the rear tires,
then tried to spin by hand while in 3rd gear and that didn't work so
I removed the right tire and using two lugs reversed onto the rotor and a large wrench,
applied my floor jack to lift the wrench causing the rear rotor to move
I had put a mark on the crank and once I had rotated the rotor a bit I looked at the mark and it had moved.
This was after the car sitting for 23 years

You should also check the wires going to the starter and make sure they are not corroded since yours was in a flood condition..

very comprehensive approach... I decided to disassemble the starter. Before going down to the garage I realised I must buy some tools, as I have only milimiter based caps. I should get inch based sizes tomorrow...

Put the car in neutral, put a socket on the crankshaft bolt and try to turn the socket. Your reasoning isn't wrong, but with a flood car you shouldn't take too many things for granted. Check it by attempting to turn it mechaincally to be sure.

When replacing the starter be sure to clean all your connections. Also be sure your battery is in very good shape.

Hi I would start by bypassing the VATS, if the security light is on it may be preventing the starter motor from getting power. You can measure the key resistance with a multimeter, find the VATS connector at steering column under dash and fit a resistor the same as your key there. The wiring can be damaged in the column leading to incorrect resistance to the BCM. Of course change the engine oil gearbox and diff oil, make sure the gas tank doesn't have water in it. If caught in heavy rain and the gas tank filler boot drain is blocked water will get into the tank. Anyway would be great if you had someone to measure the starter gets 12 volts when turning the key, to ensure the VATS isn't the issue. Good Luck and don't forget look at the simple things like fuses and column mounted switch under dash has not come loose, as the ignition key turns the pushrod that moves it. There are only two screws that hold it, the switch screw holes are slotted to allow adjustment .

Here is an update: all the fuses were checked before, VATS also not an issue. also wiring is all OK.

I have disassembled the starter, without disconnecting it. It runs OK when I turn the key... multiple times. I put it back in place.
I also took off the belt and tried to rotate the engine. It doesn't move at all...

So it's seized

I'm a bit puzzeled as there is no water in the cylinders (checked 4 on the left side), water level as shown on the first post. Oil level is also OK.
Probably it's high time to send the car to a proper mechanic...