Hyacinth is driving me bonkers! For a quick refresher, she’s a ’73 ES with a ’70 B20E that has been modified. It has the IPD Big Bore kit installed; the head has been milled (but the PO didn’t remember how much…GGgggrrrrrr..), an IPD Street Performer cam, and D-Jet with a modified IPD computer with a rheostat and a couple of binding posts and lamp cord…. It has the Allison/Crane ignition system, and I have cleaned the ignition contacts. I bought the car as a basket case and have no baseline for comparison

Anyway, she’s running (not close to drivable), and not running well. Perhaps it’s the nature of the mods, but the idle is pure cr@p to non-existent. It idles like a redneck’s small block Chevy, but maybe worse. So far, I’ve tested the MAP for leakage and resistance across the terminals per manual (are there other tests? I don’t have a spare). Throttle switch has tested fine, and both temp sensors test OK. I have a new intake gasket, new injector seals, o-rings for the injector towers, etc. I’ve disconnected the brake booster, the PCV hose, the charcoal canister hose, the aux air valve, everything that could leak, and taped off the openings. Fuel pressure reg is set to 28 lbs. Fuel is fresh premium. The engine will not idle at all at 900 RPM, and barely tolerable at 1200. The computer rheostat takes it from running poorly to not at all, and the exhaust smells very rich.

I swapped out two different stock computers, trying to take that out of the equation, and it does not seem so rich, but still idles poorly, at 1200 RPM minimum. An IPD tech stated that a slightly lumpy idle is to be expected with this cam, but I wonder if the overlap is reducing vacuum to the point that the computer makes it run rich? Or is the combination of cam and engine mods just simply going to run rough below 1200? He was not sure.

Please, any comments or suggestions before I take a sledge hammer to the car?