Hi All, total corvette newb here. I’ve watched about 40 videos and read dozens of threads on this site, and i’m looking to get some additional input.

Background on the car. “Stored” for 10 years = sitting in yard… Prev owner said it ran fine except he thought it needed a new MAP. I didn’t believe him and I’m glad.
Roof leak means there is lots of corrosion, and that’s a bit of a challenge.

What I’ve done so far:
- VATS bypass and appears verified security light doesn’t light key-on and blinks “security” when key off.
- Paperclip OBD1 diagnostics just blinks 3x12. No other codes blink.
- battery charged and reads 12.2v at the terminals
- continuity at 0.0 - 0.01 at 3 main ground points
- Checked a couple fusible links and those lines seem to have continuity
- Passenger fuse panel, all fuses intact and posts cleaned
- under dash fuse panel all fuses intact
- All 5 relays under passenger dash checked with tester and green-light.
- New plugs and Wires

What the car does at Key-On:
- the dash gauges light up.
- gauge cluster LED glows orange, no detail
- Centre Console LED lights up and reads correct. shows check engine, etc.
- Turn key and nothing.
= no fuel pump / no fuel pressure
= no starter “click”
= no injector “click”
= backup lights on all the time <- have not investigated this yet.

I have jumped the G terminal on ALDL and I don’t get any fuel-pump voltage at the fuse, and the relay *does not* click. Again, I tested the relay and fuse, so what would prevent the relay from engaging when G was jumped??

the male-side connectors to the TPS and ICS are cracked and need replacing; Would either of these cause this issue?

Thanks in Advance!

 

I’ve also just checked the 3 relays under the drivers-side.

This thing has a weird after-market stereo with what looks like a high-school wiring job.

I wonder if that could do anything?

I can’t help but think I’m missing something simple OR the sensors above are somehow killing the start sequence.

Tomorrow I will physically check with jumpers:
- Starter
- Fuel Pump

 

I was told on our CCM equipped C4s to never ever do that!!! Hopefully you didn't smoke anything.

 

Uh, me too? Nothing I found warned of that.

 

If the car thinks you are in reverse, it won’t crank. I’d at least bypass the reverse switch. Sounds like you have other issues but that jumped out to me. I’m assuming you have an auto?

I’d grab a factory service manual for your year and start some of the diags for the circuits in question.

 

That is interesting. It’s a 6 speed manual, but those reverse lights are on. I’ll address those today, and see what that does.

Also look for an FSM. as apposed to the Haynes book I’ve got now.

 

I assumed you had an auto…I would assume as long as your clutch is depressed it thinking reverse would not matter

 

You say your battery standby voltage is 12.2 volts. It should be somewhere between 13.6 to 13.8. I am better that as soon as you turn the key that battery voltage drops into the single digits which would not be enough to start

 

Fully charged should be 12.6. 13.5 or so while running, which he can’t do.

id start from the top. Check your negative cable ground. Check the ground above the oil filter.

get that FSM and start looking.

if the fuel pump isn’t priming and you don’t get a Speedo display, I’m thinking CCM or ECM related right off the bat.

aftermarket stereo **** sucks and only adds to the **** show.

the backup lights are a switch on the drivers side of the ZF6. You can unplug but to replace, you need to remove the slave cylinder. I don’t think this is a related issue to your no start / crank / fuel pressure though.

 

Locate the fuel pump relay and identify the wires with your FSM. I’m going by memory but you should have 5 wires in this connector.
12V + Hot all the time
Ground
Fuel pump feed wire
Switched power from the ECM
”Test” wire from the ALDL plug under the dash.

locate the plug at the tank and disconnect, put your test light or multimeter on the pump feed and ground at this connector. I believe there will be 3 wires in the plug, the third one is the gauge.

Put a jumper between 12+ and the pump feed wire back at the relay connector. Check to see if your test light or MM show voltage. If there’s power there, plug the sending unit back in and listen for the pump. If you have a fuel pressure gauge even better put it on the fuel rail valve.

If no sound or pressure or if the jumper you put in gets really hot, the pump is dead.

I should probably have said first that pulling the sending unit,(since it is so easy to do on the C4) should be your first step. That way you can see if the tank is full of brown goo and corrosion.

 

UPDATE / July 18

So I got real methodical today, and have some results.

- Cleaned all the terminals on the under dash relays
- cleaned the 12+ post and all the fusible link connectors
- Cleaned battery cables
- Bypassed the clutch pedal sensor

Turned over and starter kicked in first crank.

Pulled the intake snorkel off and shot a jet of starter fluid into the manifold. ZOUNDS! She lit right up.

Checked fuel rail with gauge and no pressure during cranking

Checked fuel pump ground, disgusting corroded mess. Cleaned with vinegar and baking soda.

Checked and we appear to be getting 12v to the pump.

I think I have to replace the pump.

Ill pull it and bench test it but I think it needs a swap…

More to come Wednesday!

Thanks everyone for all the great insight here.

 

Sounds like you will be into the Fuel Tank soon. I would remove all the Fuel and clean out the Tank. Its easy you can do it all from the top. Then I would blow out the Fuel line to the Filter and replace it. Now with fresh Fuel and Filter jump start the Fuel Pump with the return Hose disconnected at the Tank and pump all the remaining old Fuel into a container. This might save the Injectors. But there is a pretty good chance when You get it running it will have some stuck injectors. Mine sat for 17 Years I did the above and only had one injector working.

Elaborate how you got around the VATS ?

 

So I first used my multimeter, and tested the resistance across my key’s resistor chip. Make certain you’re scaled to “k” magnitude.

I made certain to get the chart of VATS resistances.

I got 11.88 which corresponded to the 11,880 key #15.

Then I bought a bag of blue (1% accuracy) assorted resistors. This one was marketed as a VATS assortment. I then built a little excel chart of all the resistors I had in the bag, and built a list that totalled up to 11,882 which was nearly bang-on.

I soldered then in series so the entire daisy-chain tested at 11,882 ohms across it.

Under the dash, you find the two VATS wires coming out from the column, you want the white and orange pair. Disconnect them and I took the black/black+white pair heading to the computer and snipped the connector off. Then soldered the resistor array across the ends of those two wires. Shrink wrap the entire thing into a nice little loop.

When I put the key in, the SECURITY light disappeared when I turned it on, but flashed and beeped when I turned it off, indicating it was armed. And the starter kicked over, which it would not do with VATS enabled.

 

UPDATE: July 24th

So I worked my way through the playbook. I was suspecting a fuse issue, as the relays tested good and I was not getting power to the fuel pump.

As a quick check they looked good, i cleaned the terminals with steel wool, and no dice.

Then I swapped a couple of fuses around and re-started.

The LCD was totally dead and no start, where it previously had.

The fused I swapped the FP with was the LCD. Bad fuse.

Bought an entire complement of fuses and swapped every single one since the car has sat with moisture in it for so long.

Once replaced she literally fired up on the third crank.

Full bottle of SEAFOAM through the intake, 2 fulll cans with 5 gals of premium gas in the tank.

It appears that I’m good, just need to bleed the brakes and repair the clutch cylinder, and I think I’m driving her.

Lets hope I’m not too optimistic.

G.

 

 

Ive replaced the fuel pump, strainer and filter. So i’m set there. The sender was like $600 and it works so i’m not spending that cash.

 

UPDATE!

The car runs and drives, briefly. There is no power being generated or making it off the alternator. I’ll diagnose this tomorrow. I’d rather not buy a new alternator but any suggestions on what else it might be? basically starts and runs on a fresh charge and drains out the battery after 5 minutes of driving/running.