Recommendations for tuning an '04 Chevy Suburban

I am looking to do some EFI tuning and general automotive upgrades to get the most out of my 5.3 Vortec. This is not a performance goal. I'm just trying to optimize the vehicle for road use and long-distance driving. I'm also using this as my entry into tuning.

Has anyone done any tuning with this vintage of GM vehicles?

Recommendations for software and setup re-flashing the OEM ECU?

Hey Kristan, I have done a numder of these hehicles. What exactly are you planning on getting out of it? More economy/torque/change shift points? I'm not a pro but might be able to give you a couple things to try.

Hye Cory, Thanks for the post. Based on my use, improving economy would probably be the most practical. I don't do a lot of towing with the vehicle currently, but that could change. I probably won't stress the engine too much until I do an overhaul on the valves. I haven't done a compression test recently, but I can only imagine that with 310k miles on the engine, the rings are probably well worn. I'm not looking for great gains. I'm just looking to get the most out of it until for now.

That engine is supported by HP Tuners so I'd recommend their solution. You're not really going to achieve much in the way of economy gains in general for cruise since the engine will run in closed loop and target a stoich AFR of 14.7:1. Generally you can gain economy overall because usually the PE targets are much richer than necessary. So you can lean these out to sensible values and you could also potentially raise the TPS point at which the ECU switches into PE. Some common sense needs to be applied of course because running the engine at high load and 14.7:1 will cause excessive combustion temps and can damage components.

It is possible to force the engine to run in open loop and therefore tune for leaner than stoich AFR at cruise. This will be illegal from an emissions stand point in most countries so I'd make sure of your local rules first. Personally I find that for the relatively minor improvement of tuning for say 15.2-15.4:1 is not worth the potential downside to driveability if your AFR is moving around with no closed loop to clean up any errors.

Hey Kristan sorry for the late reply, the only things I have done to improve economy on those is add about 3% spark dwell time and decesitize the knock sensors slightly, these were very conservative from the factory and the knock sensors would pull timing very easily - even just once the engine comes into the torque curve might be enough to trigger the knock sensors a decent amount before you actualy get knock. What I do is change the sensor sensativity by 2% and then datalog to to see how it goes. You will also get a bit more torque out of it by doing that. Just also listen for the slightest pinging noise from the engine. If you get that then you would want to add a bit. This is probably not the best way to do this but I have never had any issues with this. The reason it inmproves economy slightly is obvious - doesn't pull timing unnecesarily!! And the dwell time just makes your coils charge a bit longer giving you a stronger spark from the spark plug. Just don't go more than 5% on that as you might overheat the coils. As Andre said, you can't realy do a lot as far as A/F ratio as that can be dangerous. Happy tuning and as always - be carefull and use common sence!!