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When I saw yours on the flatbed, I felt super bad. That's just so frustrating when new parts are garbage. It has been almost ten months since we've turned a wheel, and since it was dad's birthday, that made it a little cooler.

-BP

Yesterday we took a trip to Summit with a couple parts to return, and a new coil to purchase. We drove the Vette and put over 80 miles of normal driving on it with no issues. The HVAC engineering we put together seems to work perfectly, bringing in actual cool air from the outside, and somehow even though we had the dash all apart for the heater core, the air flow direction still seems to function as designed. It drove the freeway at 74mph like nothing, passed a semi on a two lane and got up to 90 with no issues. The thermostat is 160 and I never saw the car go over 165 the whole trip, and it was 80 degrees outside. According to the factory gauge, the oil ran around 172 degrees which I assume it probably pretty good. We're trying to burn off fuel, but this was getting almost 24mpg as indicated by the factory system, so it's going to take some time to run this tank dry. The detonation is still there of course, but hopefully when the new coil arrives this week, we'll be good.

Looking forward to taking this to the dragstrip, and beginning the other maintenance upgrades like shocks and brakes.

-BP

Did you check the springs in the distributor? I think that if the springs are too weak,
you’ll be getting the detonation you’re hearing.

GM

All electronic in this one, no springs attached.

-BP

You could siphon out that old gas to expedite the process. I highly doubt Dad's tractor would ping on it lol.

Start driving around in D instead OD..

I actually do want to run the whole tank through. Even though it's older gas, it does have the fuel injector cleaner I put in it so I'd like that stuff to do some work. If I have to wait another week or so, it's no big deal. I've waited this long...

-BP

I got the new Pertronix coil installed today. Unlike the AC Delco coil, this one actually works. I drove it to Summit again today and unfortunately the new coil didn't fix the detonation problem. It runs good still but I think it may have actually made it slightly worse. So now I'll go after checking the fuel delivery next. With the new fuel filters already installed, I'll check the fuel pressure and see where that takes us.

-BP

it might be too lean - for under $200 you can get rebuilt injectors. it's an option when/if you run out of other options

I'm not ruling anything out right now. It's set at stock timing, 6BTC, and IMO it should really be able to run at least 10-12 degrees safely on premium gas. Once I check the pressure, I'll decide where to go from there as far as regulator, fuel pump, or injectors.

-BP

We should have a fuel pressure regulator with a gauge like WXO,
so we can change whenever we feel like it.
It does seem to effect the Vette's throttle response.

This is the one I have: https://www.amazon.com/gp/product/B000C ... UTF8&psc=1
It has special bracketing to mount to the LT1 fuel rail. The gauge is extra.

Today we had a few minutes so we checked the fuel pressure and it's functioning completely as designed and within spec, even at WOT when I hear the detonation. It provides more pressure under power, and holds pressure when it's shut off. Next up, a check of the injectors.

-BP

If I thought more pressure would help, I'd gladly put an adjustable one on there, but it's running about 38.5 at idle, and around 44 at WOT. All very acceptable numbers for a stock L98 in 1987 guise. I suspect really that dirty injectors are to blame, because literally everything else is covered IMO.

-BP

If they all test OK, I'm going to get two bottles of Chevron / Techron and run it through on the next tank. That stuff has always worked pretty well for me with GMs crappy injectors. The car does have a small miss at idle which is more pronounced now with the new coil, which is typical for dirty GM injectors I've had in the past.

-BP