Trying to Tune Dad's Truck For better MPG and Low end Torque for towing

Hello, I'm new to Hp Tuners but so far am having a blast. I've already learned a lot and have so much more to learn.
I was hoping someone could give me some guidance in which direction I should go with this tune.

My dads truck is a 2000 Chevrolet Silverado 2500 with the 6.0L LQ4 engine, 4l80e newly rebuilt transmission with Hughes towing converter that has
a stall speed of 1800 rpm, dual electric fans, aftermarket cold air intake and 40kw transmission cooler. Thank you in advance for any guidance and help you provide. I really want to learn how to do this so I can tune my own cars. I also have a 87' Porsche 944 with 5.3L LM4 I would like to tune after this.

I've included the Stock tune file and log that I took.

Attachment 102076 Stock Tune File

Attachment 102075 Log File

Attachment 102077 Charts Config

Check over the intake for leaks and exhaust for broken manifold bolts. Also check fuel pressure for proper spec.

I say this because the long term fuel trims are rather high just driving around. That can reduce fuel mileage as it's adding in more fuel than needed. Ideally if the trims are within 5% of zero you are doing pretty good.

Past that it really comes down to how you drive. It's a heavy truck that only going to get low teens on the freeway and that's if you keep the speeds under 70mph.

Enable Power enrichment sooner and run fuel better than 87 octane to get the most from the engine. If there is spark knock, that is power being taken away. This log had anywhere from 2-6 degrees of knock under heavy load. The high IAT's weren't helping either, hopefully that intake is blocked away from engine bay heat. Otherwise it's not a cold air intake like the factory airbox is.

Thanks you for the info! We had pulled the engine out, replaced all gaskets and resealed the motor. Also replaced exhaust manifold gaskets and a couple broken bolts. I'll check the fuel pressure at the rail and see if its within spec.

Yeah, I'm not racing the truck. I just want to get it running the best it can for towing our fifth wheel we just got. It doesn't see speeds over 65 usually. What do you think would be some good numbers to enable PE at?

I don't think it is honestly. It's one of those crappy aftermarket cold air intakes that has a shroud but its not completely blocked off from the engine bay heat. Ill try converting back to the stock air box with high flow K&N air filter and see what happens. Thanks again!

If it's still going to be pulling heavy loads I wouldn't go all on the PE settings, as in having it enable at the snap of your finger type thing.

Just dial in back from the stock settings which basically disable PE altogether.

I would remove the 60 second time delay, set that to zero. Lower the rpm delay from 5,500rpm to maybe 2-3,000rpm. Raise the MAP kpa enable to around 80kpa and lower the middle area of the throttle enable from 95% throttle down to 75% to match the 0-400 cells and the 4,400rpm cell. Make both the hot/cold the same. These settings should still keep it out of PE just cruising down the road and it will allow it to enable when you getting into the throttle enough pulling a hill or merging on the freeway.

Perfect, Thank you. I saw other people turning it way down and was worried if I did it would destroy my mpg while towing.

I did pretty much exactly like you said. I was kind of thinking around the same thing but wanted to make sure before I screwed something up, so thank you!

Is there anything else you would recommend tuning? Should I go through the hassle of installing a wideband on this vehicle.

Updated Tune File With PE Slightly Enabled Attachment 102078

I would strongly recommend putting in a wideband. It is absolutely needed for accurately tuning the fuel, and with some of the available math histograms, makes tuning the maf/VE tables a breeze. You're already off to a great start though.

Just a quick addendum, I'm not sure what cable you have (standard or pro), but I have a MPVI2 Pro and I have a wideband that I have set up to hook into a 12v cigarette outlet for power and then connected to a pro-link cable that I can move between vehicles in minutes. I typically install it in one of the front 02 sensor bungs and just unplug that sensor and disable the CEL temporarily while tuning. Having one of the primary O2's unplugged forces it into open loop too (from everything I have seen anyway, double check this with your application).

Ive been tuning my 04 2500 for a little while now and have come up with a decent tow tune for 87 octane. But there is quite a difference in power with 93 octane.

What gear ratio and tire size?

mine has 4.10s and 285/75/16s so its roughly 2350@70mph. And about all it wants on 87 octane is 25* timing. Going to 93 octane i can get 30* out of it and it doesnt have a tendency to unlock the converter or down shift on hills while towing. Also im commanding about 13.7 afr at 2350 rpms when it goes into PE about 70% TPS.

Stock everything with 05+ Efans.

You can run a stock air filter box (dont waste money on a K&N) and a Airraid MIT Tube for Efans since you already have them. Also get a 2002 Duramax air filter for the factory box. They drop in and have longer pleats. This way atleast you can pull cooler air from the fender well and not hot air from the engine bay.


I havent put a wideband on it but i tried the MAF tuning using LTFTs for the correction and it seems to change day to day so one day ill put the wideband on it and fix the exhaust.



Also watch out for Fuel Mixture Spark correction. I think thats the name of the table. It adjust the timing as you get into PE. (ive been using EFI Live so i cant rem what HPT calls this table)

If/when the truck is stock, I would really worry that much about a wideband. I wouldn't even change the factory PE EQ ratio on this vehicle based upon it's current settings, leave it as is and just adjust the values it takes to enable PE.

If there are no leaks and fuel pressure is normal the fueling at wide open throttle will be close to commanded.

There isn't going to be any gain that is worth it after 25 degrees of timing on the stock camshaft. If it could take 30 degrees but if it only made ~10hp over 25 degrees, it's not worth it.

Quote:

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Originally Posted by 5FDP

If/when the truck is stock, I would really worry that much about a wideband. I wouldn't even change the factory PE EQ ratio on this vehicle based upon it's current settings, leave it as is and just adjust the values it takes to enable PE.

If there are no leaks and fuel pressure is normal the fueling at wide open throttle will be close to commanded.

There isn't going to be any gain that is worth it after 25 degrees of timing on the stock camshaft. If it could take 30 degrees but if it only made ~10hp over 25 degrees, it's not worth it.

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Ok, Thank you! I enabled the PE like you suggested and I can tell a big difference in power once the throttle goes past 75%. If I were to add a wideband sensor
wouldn't it be better to have a bung welded in and have it permanent? Also Where would be the position to do this at? I have a Porsche 944 with a LM4 with some mods and would most likely benefit from a wideband on that vehicle. I might do a cam on this vehicle one day.

I still need to check the fuel pressure and for leaks to see why I'm getting knock. I do live in Arizona where it's HOT AF and we have crappy gas.

The truck does have 200k miles. Would faulty or dirty O2 sensors causes the LTFT to be so High?

Quote:

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Originally Posted by RDF1

Ive been tuning my 04 2500 for a little while now and have come up with a decent tow tune for 87 octane. But there is quite a difference in power with 93 octane.

What gear ratio and tire size?

mine has 4.10s and 285/75/16s so its roughly 2350@70mph. And about all it wants on 87 octane is 25* timing. Going to 93 octane i can get 30* out of it and it doesnt have a tendency to unlock the converter or down shift on hills while towing. Also im commanding about 13.7 afr at 2350 rpms when it goes into PE about 70% TPS.

Stock everything with 05+ Efans.

You can run a stock air filter box (dont waste money on a K&N) and a Airraid MIT Tube for Efans since you already have them. Also get a 2002 Duramax air filter for the factory box. They drop in and have longer pleats. This way atleast you can pull cooler air from the fender well and not hot air from the engine bay.


I havent put a wideband on it but i tried the MAF tuning using LTFTs for the correction and it seems to change day to day so one day ill put the wideband on it and fix the exhaust.



Also watch out for Fuel Mixture Spark correction. I think thats the name of the table. It adjust the timing as you get into PE. (ive been using EFI Live so i cant rem what HPT calls this table)

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I'm going to start running an higher octane and see what results I get.

Tire size is 29.62, Ill have to check the tire for size. Truck also had 4.10 gears.

I will definitely do that air filter trick, thank you. Have to find a stock box from the junkyard.

Here's an updated log from after I enabled PE

Attachment 102108

Try 89 octane and see what happens. Right now it could be a combination of 87 octane and the extremely hot weather/IAT temps that is see's sometimes.

Even worn motor mounts can cause extra vibrations to be picked up by the sensors too.

Poor working or just super old sensors could cause less than accurate O2 sensor readings. If the upstream o2 sensors are as old as the truck is, may be a good idea to replace them with new OEM ones.

Sounds good, Thank you 5FDP for all your help. I replaced the fuel pump and the ltft look alot better. Could be a combination of the colder weather as well, maybe. Attachment 105030

Thread revival. Were you able to get it tuned to the point you were happy with it? Any noticeable improvements in unloaded highway fuel economy?

The stock stingy PE settings can actually result in worse fuel economy. Better emissions I guess, but using more fuel overall. Allowing PE to come in when it's needed gives you more power from less pedal with fewer downshifts and for a much shorter length of time, in normal-type driving situations.

Not all, but a lot of stock tunes have PE so restricted and spark so low to allow for garbage fuel that you spend half the time with the pedal pinned to the floor going nowhere. So yes, proper tuning can improve things a lot, but it really depends how bad the starting point is.

Quote:

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Originally Posted by blindsquirrel

The stock stingy PE settings can actually result in worse fuel economy. Better emissions I guess, but using more fuel overall. Allowing PE to come in when it's needed gives you more power from less pedal with fewer downshifts and for a much shorter length of time, in normal-type driving situations.

Not all, but a lot of stock tunes have PE so restricted and spark so low to allow for garbage fuel that you spend half the time with the pedal pinned to the floor going nowhere. So yes, proper tuning can improve things a lot, but it really depends how bad the starting point is.

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This is something I have actually played around with ALOT on multiple setups over the years. From CCC Q-Jet and on with GMs.

I set the RPM delay at half the converter stall speed. I zero the time delay. I lower the PE KPA to around 60 KPA and set the torque to maybe 50%. I ramp up the entrance rate to ~1.0. I set the PE TPS value to around the point the manifold sees less than ~5 in/hg vacuum. However I set the torque converter unlock value atleast 10-15% TPS less than the PE TPS at cruising speed. I have found it more fuel efficient to unlock the converter for added torque multiplication than it is to dump fuel. Running in closed loop the engine needs less timing than in PE because of the cylinder temps in closed loop being hotter. PE spark 1-4* higher depending on rpm and air/fuel ratio. Less timing at lower rpm and leaner and more at higher rpm and richer. Done properly it is a near seamless increase in power right to the point of forcing a downshift.

Treat this like a performance tune and you will have good mileage also. They go hand in hand.

Correct the MAF table. Edge the timing table up especially in low load areas until you run into knock. Keep it out of PE when load is actually low and into PE when load is high.

These are some of the best vehicles to see a before/after gain with tuning. I love doing trucks for customers.

Quote:

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Originally Posted by Alvin

Treat this like a performance tune and you will have good mileage also. They go hand in hand.

Correct the MAF table. Edge the timing table up especially in low load areas until you run into knock. Keep it out of PE when load is actually low and into PE when load is high.

These are some of the best vehicles to see a before/after gain with tuning. I love doing trucks for customers.

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Love doing trucks too. While I tune alot of LS swaps, I probably enjoy doing the L30, L31, L21, L29 and L18s the most. They all have big torque and efficiency gains to be realized. The earlier ones have the most to gain, especially when converted to a P01 or P59 where lean cruise can be implemented.

My L31 based 383 runs on a DBC P59 using a Mexican 2005 GMT800 L31 base file. Love the way the 11:1 aluminum head 383 pulls on E85.

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