So my wife took the hummer we just bought out on the highway and at 120 Km/hr it won't go any faster even with the pedal to the floor. So i guess it's been programmed with a speed limiter or governor as I was always taught.
I see there tools like HP Tuners that work for some but a little out of my price range for a one time use, any other way, i see sone OBD tools that are AFM/DFM disabler is this the same as a speed limiter ?

Any options other then the garage ?
2006 h2 hummer

 

The Diablo tuner is worth the $360 US dollars as far as I'm concerned. You can turn off the AFM for engine longetivity. You can set or turn off the speed limiter. You can change your tire size in the ECM and your speedometer will be correct. You can tighten up the transmission shifting to help your transmission run cooler when towing and live longer. You'll find that if you bump the power up a little bit, with one of the canned tunes included, you can get an extra two MPG out of it as long as you don't drive it like a race car.

Or you can spend two-thirds the cost and have a shop just plug in and turn off the speed limiter. It's not unusual for a rental car company or one in a business fleet to have a speed limiter set fairly low.

 

Sorry, I just noticed it's a 2006 and I don't think you have the AFM/DOD in that model.

 

So AFM is different then a speed limiter ?

 

AFM is not a speed limiter.
AFM is active fuel management, also referred to DOD, displacement on demand. 2006 H2 I'm sure is too early for that. I think they started it around 2008. It is GM's system where 4 cylinders are deactivated at cruising speed and under light load in an effort to save fuel. It can make the switch from 4 cylinders to 8 cylinders, back and forth multiple times a second if necessary. It's a rather elaborate system prone to failure with unique valve lifters. Considering your fuel mileage usually gets better with a deactivated, most people at least deactivate it in the ECM to extend engine life somewhat. A full removal involves changing out the camshaft and lifters.

There really is no device referred to as a speed limiter. It's a simple setting in the ECM. Like adjusting the volume on your cell phone. Now imagine if you wanted to change the volume on your cell phone, and you had to take it into Samsung or Apple and pay $200. It's really not that much different, LOL.

With that said, your symptom is very likely something else going on and you should check for codes. In the early 2000s most GM vehicles were shipped from the factory with the speed limiter setting at about 100 mph. When you hit that it sends a signal to turn off the fuel. You might have plugged catalytic converters. Looked at your air filter lately? Do you have a check engine light on? And does the light come on when you turn the key to the on position before starting the vehicle? I've seen many cases where people take out the bulb when selling a vehicle, to hide the fact there's a problem.

 

Nope, None of the H2's have AFM/DOD either on the LQ4 in the 03-07 nor in the L92 in the 08/09. I thought I read somewhere the H2's were limited to 99 mph, but you mentioned 120KM which is only about 75mph. Perhaps they had different rules for Canada?

 

I would expect different countries to have different requirements when imported.

The L92.... Has got to be the best engine. It's the L94 without the AFM, but retains the variable valve timing which helps on low end torque. The only downside to the 6.2 over the 6.0, is parts cost a lot more because every hot rodder out there wants a 6.2 LS motor. It's hard to argue with 400 plus horsepower out of the box with better fuel mileage. On the flip side the iron block 6.0 will last longer, which can only be due to having less power. But both are fantastic engines in their own right.
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Definitely not the bulb, it's there when the key goes on, the check engine light.
if it was a clogged air filter or converter wouldn't the engine rev up when you have the pedal to the floor not just stay at a constant 120 km with no chamge in the tack ? I find it funny that it limits at 120 which is exactly 10 km over our maximum speed limit of 110 km/hr in canada.

 

Yeah, most likely that was a requirement by Canada. Simple change of the setting.

 

I've never seen governors or speed limiters come from the factory in canada, usually I've seen them on fleet vehicles, usually in the oil patch.

I just looked at the car fax and it was registered in 06 with 10 miles at Michigan then in 07 in Arizona as a commercial vehicle. My guess is thats where it was limited.
best quote I got so far was 500 to reprogram stage 1 or I can order a used programmed wcu off ebay for $200.