HELP! Why does my '92 firebird V6 shutdown at 110 MPH on the mark. I tested it for the first time tonight after buying the car and doing some modifications though minor and it feels like the computer control shuts it down at exactly 110 MPH!! HELP!!!

 

Yup, that's exactly what's happening...you're hitting the Speed Limiter in the eprom and it shuts off the fuel. The only way to fix it is to have your eprom modified to remove the speed limiter.

You can either get into eprom burning, which isn't a bad idea if you plan to do modifications to this car (or any future GM OBD I car). Or, find someone in your local region (check out your Regional Board) and get them to make the change.

Unfortunately, the DIY Prom Board is only tor learn how to burn eproms yourself and not prom requests. If you lived near me, I would ask you to come over and bring a case of beer. I could fix it before I even finished the first beer - that's how simple the change is.

FYI, the programming on those V6 eproms is very mild. There is lots of room for improvement in the spark tables which yield a noticeable gain. But you need to get into eprom burning to learn that.

 

In the late 80s all cars had speed limiters installed so you couldn't sue them for letting the car go faster then the tires are rated for on the car. All tires have speed ratings and they were only putting cheaper tires rater to 80-110 MPH which can fail badly at 140+ and you could then sue. Cause they knew the car would go that fast and knew the tires it came with new could not handle them speed for very long......

So instead of putting better tires on cars. They put on speed limiters.

Don't be a fool and disable you speed limiter and be running cheap tires not rated for it. All tires have speed ratings and going over that speed for very long is dangerous.

That should almost be the official answer for all mods here. If GM couldn't get past liability issues letting folks go that fast on cheap tires. Official forum mods telling folks how to disable that option with out a warning just opens things up for ligation.

 

Thanks REAPER. I live in Sothwest Florida. Where are you? Anyone else that may be in my area that could help with this I would love to hear from you. Also a good note about the properly rated tires. That is obviously very important!

 

No, the official answer is, it's against the law to drive beyond the posted speed on a public highway. It's usually against the law to modify your engine in most states. All information here is intended for off-road use only.

Should anyone choose to take this information and use it on a vehicle that's going to be driven on a public highway, be prepared to suffer the consequence of your own action.

We do not force people to come to TGO or force them to use this information.