Figured I'd give an update on the 88 GTA, now that I've been driving the car for about 5 months, and the maintenance/issues that have cropped up so far. I had figured out the major issues with the car, but was expecting other potential issues to crop up as the car was finally being driven as she was meant to. Unfortunately, the previous owner had let the car sit undriven for a long time (probably about a year) and that's the worst possible thing you could do to an TPI (Tuned Port Injection) setup that's in this car.
After I had gotten the car, I would occasionally have an issue where I turned the ignition over, but nothing would happen, quite literally, as in the car was completely dead. The few times this happened I was able to start up the car after turning the key over a couple more times. I figured it was just a bad ignition cylinder in the steering column, and figured I'd change it out. As it turned out, it was slightly more than that. About 2 months after getting the car, I had a long drive and stopped to get gas. And of course the car wouldn't start up at the gas station when I was ready to leave. This time nothing came to life no matter how many times I turned the key. The car was completely dead. I called a friend who came over in his Jeep with some tools to hopefully trouble shoot things. We tried a few things, including jumping the starter solenoid, but there was nothing. That's when the light dawned on me. I'd had the infamous "VATS" (Vehicle Anti Theft System) failure that these cars are known for.
A little history on the "VATS". GM back in the 80's was having issues with very high rates of theft of Corvettes, Firebirds, and Camaros. So around 87 they introduced the VATS in the Corvette, followed by introduction across of VATS across all Firebirds/Camaros in 89. The VATS worked through a system of sensors. The ignition key has a chip built into the shaft, and has a very specific resistance value. This resistance value is read by a reader in the ignition cylinder, and the signal (if appropriate) is transmitted through 2 wires through a connector to the VATS module. The VATS module then sends a signal to a) the ECM to fire the fuel injectors, and b) the starter relay to fire the starter. So if the resistance value is incorrect (i.e., a wrong key or a damaged chip), the entire car shuts down-no fuel, no starter! And these cars are known to have issues with the wire leading from the ignition cylinder that transmits the signal to the VATS module (after decades, the wires break or the ignition cylinder wears out). The system works great-as I can attest to! Anyway, at this point I had to have the car towed. Once I got home I plugged in my OBD reader into the car to make sure that was the issue. And yup, I got the infamous Code 46 flashing through my SES light on the dashboard. Then I had to do some research on the fix. Turns out GM would use 1 of 11 resistance values randomly chosen per car. So to figure out the resistance value, I had to use a voltmeter across the chip (pic of chip below) and figure out what my car had. Once I did that, there's a few different ways to fix the issue. I decided to just purchase a resistor module that had all the 11 resistance values built into it. There's a couple folks that make these modules and sell them on eBay, since it's a known issue. You just have to flip the correct resistance switch, access the ignition to VATS module connection under the hush panel under the steering column, disconnect the ignition wire, plug in the resistor module, and voila, the module now always gets the correct resistance value, despite the ignition cylinder wire being disconnected.
Well, now came the interesting part. Everything I read was referencing model years 1989 onward, but nothing for 88. But I knew I had a VATS system. Even the ignition cylinder wire was a different color than what it should have been based on everything I read (yellow vs orange). I had to do more digging to make sure I was getting the correct resistor module, and found that 1988 isn't really known as a VATS year for the F-Body cars (Firebird and Camaro) since GM introduced it in 1989. However, GM, who I might add is known for pulling BS like this, had decided to phase in the system on 1988 model year GTA Trans-Ams ONLY, and only on those made DEC 1987 onwards. This is very rarely known even across multiple forums. Mine was made in April 1988. While digging, I found someone who had the original GM bulletin issued to dealerships, and he sent it to me. That explained the weirdness with the wires, since they standardized everything from 1989 onwards, but 1988 is a weird phase in year. Even my starter relay isn't in the same location as the other model years. At any rate I got the module plugged in, and voila, car fired right up! So that was an interesting issue to deal with.
Other maintenance I'd had on my to do list was repacking the front wheel bearings. I finally got around to doing that-the bearings in the car were still the original bearings from 1988, and were in great shape, so I decided to just repack those bearings instead of replacing/repacking, since those AC Delco bearings are way better quality than what I'd get these days.
And I hit 100000 miles on the car. The car doesn't have cup holders or a glove box, but I think I can live with that :)
Ignition key with the VATS chip
The ignition cylinder to VATS module connector (ignition cylinder wire in yellow)
Ignition cylinder VATS wire disconnected and resistor module connected to VATS module connector
Close up of resistor module
Wheel bearing repacking on a not rainy day. Couldn't use my buddies garage since he was messing with a 1970 Mustang fastback he had just picked up a week earlier for really cheap, but lucked out on having a good weather day!
I was working on the 88 on a beautiful sunny Saturday while trying to figure the VATS issue, and some of my friends who were each driving around on their own randomly showed up at my place. My colleagues 2023 Dodge Challenger Scat Pack, my buddies 1980 Camaro, and another friends 1969 Camaro in the background.
This was a 1980s photoshoot I wanted to do (from a couple weekends ago). My buddies supercharged Ford Fox Body Mustang and my 1988 Pontiac GTA Trans Am.
Sunset at Eagle Beach
A long time ago these 2 were street brawling each other. Now they're just happy that the other survived to meet up for a sunset in Alaska
100,000 mile mark. Original engine running great.
GM GTA VATS Bulletin
