120 MPH Cluster

[Supercharged111]

Well, I did all the research and figured out I can swap the odometer, and the benefit is 120 is cooler than 100.

True on the odometer and double true on why you should have one of these clusters.

FYI, one can "tune" the flutter out of the fuel gauge with tuning software, easily... if you have access to tuning software, of course.

This is probably common knowledge but I thought it worth a mention.

Not common knowledge on my end, if you have any more info on that I'm all ears. My understanding is that the hummingbird needle is caused by the 98-00 trucks having the fuel level gauge run off the PCM via PWM instead of the sender in the tank returning a high/low resistance value to the gauge itself. I have EFILive and have never seen anything that would fix this. Doesn't mean it's not there.

 

[1998_K1500_Sub]

Not common knowledge on my end, if you have any more info on that I'm all ears. My understanding is that the hummingbird needle is caused by the 98-00 trucks having the fuel level gauge run off the PCM via PWM instead of the sender in the tank returning a high/low resistance value to the gauge itself. I have EFILive and have never seen anything that would fix this. Doesn't mean it's not there.

The base PWM frequency is 60Hz for the fuel gauge. Tuning SW (e.g., JET's) will let one easily double the PWM frequency to 120Hz. It's a single change of one parameter. The mass of the fuel gauge does the rest (i.e., it acts as a low pass filter).

Easy Peasy.

Let me know if EFILive supports this. I felt it would be common.

 

[Supercharged111]

The base PWM frequency is 60Hz for the fuel gauge. Tuning SW (e.g., JET's) will let one easily double the PWM frequency to 120Hz. It's a single change of one parameter. The mass of the fuel gauge does the rest (i.e., it acts as a low pass filter).

Easy Peasy.

Let me know if EFILive supports this. I felt it would be common.

That doesn't mess with how the gauge reads?

 

[1998_K1500_Sub]

That doesn't mess with how the gauge reads?

Didn't for me!

1998 with OEM ECU.

The change doesn't alter the duty cycle, only the repetition rate (frequency), so the average voltage remains the same.

Meanwhile, the mass of the gauge acts as a low-pass filter. Doubling the PWM frequency moves it further above the cutoff frequency of low-pass filter (gauge), making the "buzz" negligible but displaying the same average value (fuel reading).

 

[Supercharged111]

Didn't for me!

1998 with OEM ECU.

Alright I'll have a look, sounds like something I would have blown past because it sounds in my mind like it'd make the gauge read weird. But if that's the base, and the tank capacity is defined, it stands to reason it ought to able to math out the rest.

 

[JCribb]

FYI, one can "tune" the flutter out of the fuel gauge with tuning software, easily... if you have access to tuning software, of course.

This is probably common knowledge but I thought it worth a mention.

Glad you mentioned it, because I didn't know this.

 

[1998_K1500_Sub]

Glad you mentioned it, because I didn't know this.

I’m sorry I waited so long to mention it, I truly thought it was common knowledge to fix the fuel gauge buzz with an ECU configuration tweak.

I learned about it from someone else, long ago.

 

[Supercharged111]

I’m sorry I waited so long to mention it, I truly thought it was common knowledge to fix the fuel gauge buzz with an ECU configuration tweak.

I learned about it from someone else, long ago.

Far as I can tell, EFILive doesn't have this.

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[Z71Hobbs]

Not all 95+ trucks. Wont work well with the diesel trucks.

Ive tested them in my 6.5 and they work fine.

 

[1998_K1500_Sub]

Far as I can tell, EFILive doesn't have this.

If you sniff around the configurable parameters (not just those obviously related to fuel) might you find one related to a PWM "frequency", or "period", or "rate"?

I made the change using JET's tuner. I'm not even sure it's obvious, there, what to change... they might just have a changeable parameter simply named "PWM frequency". I did it perhaps 10+ years ago and haven't looked at that parameter since (and I don't have the JET tuner installed on a laptop near me so I can't post a screen grab).