I bought a 97 7.3l a while back and now that i have driven it a bit i have noticed that the truck wants to run at lower rpm's. usually when i cruise around in town it runs at about 1200 rpm? my dad's 7.3 usually runs around 1500 rpm in town? I also noticed that when you quickly accelerate, it goes to about 1700 rpm in first, and then already shifts to second, and then i am at about 1300 rpm??? The guy i bought it off of said he never chipped it, and to his knowledge the truck hasnt been chipped. He did however use it for fuel economy testing for a trucking company and found that the truck got around 20-21 MPG doing 110 km/h (68 MPH). My truck has alot more power then my dads (not sure if its becuase my dads has 700K, and mine only 280K??) i couldnt see it making this big of a differance in power?

Thanks, Simon

 

These installation instructions will show you where it is:

http://www.dieselmanor.com/docs/dmi/DM-TS73LMPC15.pdf

Diesel Movies - I install a DPTuner F5 chip in my buddies truck. Positions were Stock hi idle 60tow 80econo 120 race 140smoke.

You have to pull the PCM out to check, which is underneath the dash by the e-brake.

A different cruise speed could be 100% gearing. If they are both 4x4 trucks, then your axle ratios are either 4.10 or 3.55. Your dad's truck might have 4.10 and yours has 3.55, so in the same gear at the same speed, you will have fewer revolutions. Tire diameter also plays a role in the RPM to speed ratio.

 

You don't need to pull the PCM to check for a chip; you will be able to if there is anything sticking out of the back of the PCM once you pull the kick panel and posibly the e-brake bracket.

That being said, a chip has no control over your cruise rpms (although, it can control the shift points in an auto). RPMs are determined entirely by the drive train (tire size, differential gears, and tranny gears). I'd bet you have 3.55s and your dad has 4.10s.

 

Alright, i might try and pull out the pcm this weekend and check, and also check the gear ratios.
Thanks alot, Simon

 

Do both trucks have the same gear ratio? That could explain the difference in power and acceleration.