With the price of gas lately, I've been working on my pickup to get some extra fuel mileage. Its a 72 GMC half ton with an 87 350 TPI engine. I have headers, airfoil, AFPR, and CAI. Otherwise its a stock engine. I'm also running a 700r4

I replaced the front brake calipes cause they were dragging, changed gears from 3.08 to 3.73, and got a larger airfilter. All these things have improved my mileage up to 14.4 that I got the other day. Yes, the 3.73s improved mileage. The 3.08s with 28" tall tires were just too much for the highway and lugged the crap out of the 350 in a 4000 lb brick. Not to mention the extra acceleration they provide

So, I'm still in persuit of some better mileage. I was thinking of turning the AFPR back down to stock pressure to see what that would do. What is the stock pressure though? Oh yeah, I can't remember what the initial timing is....I'm thinking like 2 degrees advanced from stock...but not sure.

Any other suggestions on improving gas mileage?

Thanks
Derek

 

There are the usual tips for a pickup:

• Use a tonneau cover or "Air Gate", or simply remove the tailgate;
• Don't carry around any extra weight or cargo;
• Keep tires inflated and wheels aligned;
• Remove any bug deflectors which may be mounted out on the edge of the hood;
• Change the oils to synthetic, including the rear axle;
• Keep a clean air filter;
• Use cruise control when practical.

Since you have the TPI, there are more things you can do to squeeze out some more mileage:

• Reprogram to enable Highway Fuel and Spark Modes;
• Program the TCC lockup for a few MPH lower invoke and release;
• Reduce target idle RPM tables to minimums;
• Increase the ESC attack and recovery rates, and run a more advanced timing;
• Install a working EVAP system in the truck. You can lose up to 7% of the fuel in the tank through evaporation every five days in elevated temperatures like mucj of the country is experiencing. That's an immediate 7% increase in mileage, since it's fuel you wouldn't even have without an EVAP system;
• Make sure the O² sensor is generating a good signal;
• Change the thermostat to 195°F to maintain a higher coolant temperature;
• Make sure teh EGR system is functioning to allow maximum ignition advance;
• Use the lowest octane fuel you can without excessive detonation.

 

Hey, that's a good one. My truck doesn't get driven very often, so generally speaking it takes a month or more to run through a tank of gas. Maybe this is my big problem. Thanks for the advice.

 

Basically what Vader said.

He's a smart guy :-)

Tuning your engine for your trucks actual application might get you more mileage as well. Even before dipping into everything like highway mode and the like.

Every application is different and a stock TPI in a 72 truck is a lot different than a 92 Camaro :-)

Also I think Vader and I are the only ones that ever bother to mention a working EVAP system. Most people argue that it does nothing, but if the gas loss was so inconsequential, would we really be forced to equip every new vehicle since like 75?(not sure on date) with it?

later
Jeremy