1989 Pontiac Trans Am GTA Fuel Injection Tuning - 101 Tech Idle Mischief

Coil And Wires - We needed...        read full caption Coil And Wires - We needed to remove the coil bracket from our stock coil to mount our new Moroso ProCoil. The arrow points to the nub that was left when the stock coil's mounting rivets saw about 20 seconds on the grinding wheel. The new bolts are included with the Moroso coil.

While grinding on the rivets,...        read full caption While grinding on the rivets, the stock coil vibrated badly in our hands, leading us to realize that its body was actually loose on the thick metal magnet that surrounds it. We found out how important this discovery was once the new coil was in place.

As we journey down the sometimes rock-strewn road of Third-Gen Trans Am care and feeding, it's helpful to make sure the basics are covered. Otherwise, installing all the fancy parts in the world will be met with limited success.

Mentioned in a previous story ("Third Bird Heard," Jan. '07), the Third-Gen TPI Trans Ams are fun to drive and downright cheap to buy, relatively speaking, but more than anything else, they are a great platform on which to learn. To those who aren't familiar with port fuel injection, it can be somewhat intimidating at first, while to others more acclimated to later systems, they appear a bit archaic. But the biggest problem with the breed is that because of their current values, most have suffered from too little TLC, and in some cases, a complete absence of simple maintenance.

Apart from the normal wear and tear of a 15- to 25-year-old car, TPI Third-Gens have proven to be generally reliable, but don't mistake that for a free pass in regard to tuning them. In this article, we provide a few simple techniques to ensure that your TPI car is running as smoothly and efficiently as it should.

Since we only recently replaced the spark plugs, distributor cap/rotor, and air filter, we won't cover those in this story, but there are other wear items and adjustments to be made that should also be a priority on your to-do list. Please note that these adjustments should be done in the order in which they are presented, as the value of each is dependent on the one that precedes it.

Conclusion
Now that our TPI system is properly adjusted, we buttoned it up and went for a drive to let the computer "learn" the new settings. We were very pleased with the results, as the T/A started much quicker, the "hunt" in the idle had disappeared, and throttle response was more crisp. Even the transmission seemed to shift exactly where and when we thought it should, regardless of throttle position.

Sometimes it's the small things that make the big differences, giving our Third-Gen a refined and well-tuned feel and dramatically adding to the enjoyment of driving the car.

Parts List