1990 Corvette Z51

[TireSmoker]

Lots of progress today. It even fired it up!

I ended up tapping the runners and drilling the plenum and it turned out being way easier than I thought. The holes didnt need to be drilled out any bigger. I used a 5/16-24 tap. Dave Speece came over and gave me a little trick for getting the tap started squarely. He took a little piece of wood and drilled a 5/16 hole on my drill press. We ran the tap through the wood, which took a little effort. Then just leave a little tip protruding on the bottom, hold the wood against the surface and tap away. It probably took 5 minutes to do all of them.

After that, we drilled out the four holes in the plenum to 21/64.

I need to get some button head fasteners. The casting hump is too close.

With 3 of the 4 bolts in place, we put the lid to see if it would start. Sure enough, it started right up, although that open hole provides a good vacuum leak. The good news is it sounded good!

Next up will be fixing the heavy rattle in the cat converter. I'm gonna take pleasure in guttin' you, boy..

[Basement Paul]

So do we know what the real problem was? You mentioned the injector guy said he thought yours were ok...

-BP

[TireSmoker]

Remains to be seen. I still think there was some shit in there. But now, there isn't!

I'm excited to take it for a test drive this week.

[Blue_69_malibu]

Going back two or three posts, I just want to add......Tap, Tap, Tap-A-Roo.

[Basement Paul]

Not sure of the condition of your fuel filter, but if it's unknown, it might be good time to change it too.

-BP

[TireSmoker]

Test drive complete, but the problem remains.

I eyeballed the fuel filter when it was up in the air last night and it looked relatively shiny/new-ish, but found no reference to it in this thread, so I guess I've never changed it. I'll order a new fuel filter. I also ordered a fuel pressure test kit. I think you guys have said a fuel pump is a pretty easy job on this car.

-Dave

[TireSmoker]

Worked on the Corvette again today and made some progress. Speece came over to help and we knocked out a few things.

*) internal plenum bolts replaced with low-profile button head bolts with a dab of blue loctite.

*) removed exhaust, found converter was already gutted, which saved a bunch of work. It had a set of those soft aluminum header gaskets and one was beat up pretty good. A trip to Turneys and Autozone yielded a new set stainless collector bolts and new aluminum gaskets. Everything came apart and went back together easily. The good news is that the exhaust rattle is gone!

*) installed new fuel pump, fuel sending unit, and fuel filter. The good news is, the car starts and runs. The bad news is I'm not seeing anything on my gas gauge. The other bad news is that I had trouble with the gas pump at Sunoco clicking off with anything but the absolute slowest pace. what the heck?? It was a struggle to get one gallon in. But at this point, the entire fuel system has been refreshed from pump to filter to injectors. And the worst news is the the problem STILL persists.

During the test drive/gas run, despite the mis-fire, it still feels pretty strong and should feel *really* good when correctly firing all 8.

On to ignition troubleshooting..

[TireSmoker]

Found #5 plug wire arcing to the header through a seemingly intact boot. Grabbed a spare wire and its running much better again, woohoo!!

[MostMint]

Found #5 plug wire arcing to the header through a seemingly intact boot. Grabbed a spare wire and its running much better again, woohoo!!

I've had weird problems like this with older wires. Sounds like another trip to Summit is in the cards for you

[TireSmoker]

This was one of the the wires that got replaced after the Mid-Ohio fire. It's relatively new-ish. I should have enough stuff in inventory to make a proper replacement. Right now it's a too-long blue wire amongst a set of red wires.

I'm looking forward to getting some miles on this thing in the spring. Maybe even an autocross.

[MostMint]

This was one of the the wires that got replaced after the Mid-Ohio fire. It's relatively new-ish. I should have enough stuff in inventory to make a proper replacement. Right now it's a too-long blue wire amongst a set of red wires.

If you can't take the heat get out of the engine compartment

[wxo]

installed new fuel pump, fuel sending unit, and fuel filter. The good news is, the car starts and runs. The bad news is I'm not seeing anything on my gas gauge.

When Fred visited Raleigh last June, we worked on a blown piece of hose coming off the fuel pump.
When we pulled out the fuel sending unit assembly we also saw the reason for the fuel gauge malfunction. The float arm was missing!! Obviously it was floating somewhere in the tank, but we couldn't see it. So I took a long piece of coat hanger wire and went fishing. As I did this, the float came floating by the access hole as I disturbed the gas in the tank. We fished it out and saw that it had just come undone from the fuel sending unit. It just clips in like carb linkage. To prevent this from happening again, Fred suggest using a very thin zip tie to fasten it more securely. This worked great.

[TireSmoker]

The bad news is I'm not seeing anything on my gas gauge. The other bad news is that I had trouble with the gas pump at Sunoco clicking off with anything but the absolute slowest pace. what the heck??

Good news -- I drove the car to Chardon over lunch and put 17 gallons without any issue and the gas gauge was showing full. Maybe it was just that first gas pump at Sunoco that was bad. I'm calling the fuel system done. Sending unit/pump/filter/injectors professionally cleaned.

It's sooo much nicer without the exhaust rattle.

Its running pretty good, actually.

Next up, get the headlight motors working. Then I should be able to drive it anywhere/anytime.

-Dave

[Blue_69_malibu]

But Lumbergh called and said Friday was a Full Day.....

Seriously though - nice job!!!

[TireSmoker]

Well a couple steps forward, another step back. It now has a bad exhaust tick/leak, on the passenger side. The difficult side. I can see the rear-most bolt is missing. It's not easy getting in there, as I already made an attempt. Replacing that gasket and replacing the bolts is going to take some patience. The car came with these https://www.stage8.com/ but I see the e-clips missing on a couple bolts on the passenger side, so the little plates fell off and they've probably backed off.