PID $04 - Engine load 2003 sunrban 8.1L

[Ries Robison]

 

Hello,

 

I have a 2003 3/4 ton suburban with the 8.1L stock engine.  I do have a custom tune.  I use the truck to pull our 9k lbs travel trailer.  I have the Scan Gauge scan tool and I display the "LOD" parameter.  From the user guide the "LOD" parameter pulls PID$04 that returns percent of engine loading. 

 

When pulling the TT under full throttle (ok maybe 90% throttle) I am only seeing this LOD return value of "50" at ~3200 rpm.  The HP parameter also returns ~250 hp.  Specs show 8.1L is capable of ~320hp.  Is this telling me I am never getting max output of the motor?

 

In general it pulls better than my 5.3 L, but maybe not as good as I would hope.

 

Thanks in advance!!

[Jsdirt]

14 years in auto repair and I've never heard of that parameter. I wouldn't put much stock in what that's telling you.

 

As far as making power, even modern engines are the same as the old days. Gotta make 'em breathe. Free'er flowing exhaust, uncorked intake (Cold Air Intake, bigger / free'er flowing air filter), and more fuel all add power. The 8.1 should have a completely different power delivery than the gutless-off-the-line 5.3. Should have the opposite power, actually - all right there the moment you hit the pedal, then signing off much earlier than the 5.3 in terms of revs. The 5.3 doesn't even start making decent power until 3k RPM - kind of the opposite you want for towing. That 8.1 should have a good chunk right from the bottom, and pull nice all through the midrange.

 

A clogged catalytic converter would REALLY choke up that engine. Kills both power and fuel mileage. If it were mine, I'd look into a cold-air intake, free'er flowing cats (if required in your state), long tube headers, & a complete system from the headers back. Will cost a bit of cash and be a bit of work, but the payoff will be well worth it. More power with not much change in fuel mileage -if anything, mileage will be better. A win-win.