I did this with my Fiero last summer, and it had a flat tappet camshaft. I am no pro; this is just my hobby car!

In general, prepare/test as much as you can in advance of the actual first start. This is to reduce the potential for cognitive overload while the engine is running and you have other things to look after.

For instance, I tested that the ignition system would fire sparks:


You can test other outputs similarly (injectors) using the output test modes and such. Check that the inputs are all reading correctly, calibrate TPS, etc. Suck/blow on the MAP.

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It took me about half an hour to get the engine started after my first try. In the beginning, when it was cranking but not firing, I started searching for hardware problems. Finally, there were no hardware problems; the tune simply wasn't injecting enough fuel. After about half an hour of disorganized startup attempts, enough fuel had accumulated in the ports to get the engine running.

You might want to increase the cranking fuel incrementally until the engine fires. Worst case if you flood the engine, simply floor the gas pedal to clear the flood; it may fire at that time.

In the very beginning, you'll need the laptop in the car at all times to make constant adjustments.

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Pretty soon after starting up, you'll want to confirm the ignition timing with a strobe lamp. Look for any fluid leaks. Keep the engine alive with the throttle as needed.

Once the engine has warmed up, start driving! No point trying to get the idle perfect, since the idle tune will be in constant evolution for a while, just like the rest of the tune.

People think you need a perfect tune to go driving, but that's not really true. Especially when the engine is warmed up, it will be pretty tolerant of poor tuning. Just to get the engine running smoothly as quickly as possible, I targeted an AFR of 12 across the board, with reasonable spark. Too much spark retard is not good. Later on you can work on leaning out the mixture.

It will pop/hesitate/buck/bang, but that's OK, just get to driving... get some ring seal as you say!

You can build up your tune incrementally. First, work on the idle area first. As you rough in that 1st island, extrapolate to the second, fine-tune, and continue outwards.


I would say that my engine saw its first boost after two hours of runtime (perhaps 4x half-hour tuning drives).

Don't drive too far from home in the beginning until you have confidence in the setup.

[This message has been edited by pmbrunelle (edited 06-15-2021).]