Hey folks, was wondering what makes the speed limiter on my 1998 z34 engage. Is it based on TPS position? and what exactly happens? Is fuel flow terminated? Or spark? any and all info is appreciated.

 

I have no idea what "Triggers" it....

But my 1999 Monte Carlo Z-34 hits its limit at 112 mph!
It doesn't take long to hit that speed either!

Maybe Jason (Manic) will chime in and let us know.... Hes able to reprogram a PCM!

Or possibly someone else who knows.

 

Yeah, mine kicks in at about 110mph. just wondering what makes it do that. a reading from the transmission maybe? I'll stay tuned in 2c

 

The speed limiter "kicks in" when you meet a certain speed. There is a rev limiter to prevent you from revving the car too high as well. There are a few things that can be done if the car meets a certain speed. Most noticeable is deactivating the fuel pump. If you are interested in removing the speed limiter, even though you are out my year range I have list in the link below, I can probably do it (I would ask for you to PM me you VIN so I could check it out).

Here's a link to some PCM services I offer:
https://montecarloforum.com/forum/pr...impalas-42773/

 

Thanks 4 da info maniac. I'll get back 2 u about the PCM

 

3800 performance offers a reprogrammed pcm that doesn't have a speed limiter, and offers other things as well. I put one in my 2000 SS, and I think it was worth the money I spent.



PCM for Monte Carlo v1.0: 3800 Performance

 

When it hits the limiter it cuts fuel to the injectors and pulls timing, not good for the engine.

 

Mine no longer has the "limiter" in operation... Thanks to Jason! (Maniac)
Thanks Jason!

 

Correct. it is a deactivation of the fuel injectors. at a specific speed it will start shutting down 1-2 injectors and then if you keep going it will shut them all down until you get below the preset speed.

Years ago when i first got my tuner i removed the limiter. I desided to push the car and try it out. the stock limiter on a 96 Z34 is 118mph. well i went for it and was going 121 when the car desided it needed to shift... INTO 4th gear.... the car misfired and i thought i blew the darn thing up. I had not clue what happened at the time. but when i got off the highway and looked at the data i saw it. the rpms at 122mph in 4 and overdrive were something like 1000 or less. it was no wonder the engine nearly cut out and stalled. This forced me to learn about how to tune shift points. a few years later i tried it out again and hit 127 before i chickened out.

bottom line and point of the story is make sure to have your shift points adjusted as well when you remove the topspeed limiter. GM never intended the car to reach that speed so could care less if the rpms were that low.

 

Hey so I know this is going to sound stupid, I know a fair share of things but I don't know how OD works In these cars, its a lower gearing ratio then just 4th gear right? I'm not really the best with transmissions and don't fully understand them...

Edit: ok I'M not sure exactly what I was asking their... But anyways What I mean Is the car will shift into OD aka 4th which is the lower gear ratio than 3rd aka D right? But the one time Iv gotten my car upwards of 90 it was hitting pretty high on the RPM's. Whats our max speed in 3rd then?