For many years I used a stationary Corvette engine on a test stand to calibrate fuel injection units. While I was always able to calibrate units to GM specifications using this set-up, some running problems didn’t show their symptoms at all while the unit was being tested.

I decided several years ago that stationary testing wasn’t good enough for my customers. No FI owner wants to be turned into a test monkey by his mechanic. I needed to be certain that I had found and corrected all running problems before I shipped an FI system back to its owner.

An engine must be under a heavy load to fully test the performance of the FI system. For example, on an unloaded stationary engine an FI pump with excessive gear clearance will provide enough fuel to rev the engine to 5,000 rpm. However, in a 3000 pound Corvette test car, a pump with loose gears will cause the engine to fall on its face when you floor the accelerator pedal. There really isn’t a practical way to simulate every effect of car acceleration on the FI system other than to install it on a Corvette and drive it hard.

My testing program includes driving every FI system I repair under real-world conditions. I also use an instrumented chassis dynamometer to check the air/fuel ratios of each unit under acceleration and cruising loads. To handle this testing I maintain three Corvettes set up to receive customer units and distributors. Two are 1963 convertibles. The third test car is a ’57 model.

I keep my own FI adapter manifolds installed on these test cars. That way I can quickly install and remove the customer’s unit and distributor without draining any engine coolant. My road testing includes some cold engine operation as well as some steady speed cruising after warm-up. The toughest test of any unit is hard acceleration through at least three gears, and I perform this test at least twice.

I’ve learned a lot through my road testing program. I doubt I would have ever encountered some of the FI problems I’ve had to solve if I had just kept using that stationary engine test stand.