4L60 shift 1>2 speed on 12587603

[ColPaul]

My dad lives in a subdivision that has a pretty slow speed limit and wants the transmission to shift into 2nd sooner to lower the RPM when creeping around the block. I adjusted the 1->2 shift table (D0901 - Part Throttle Shift Speeds - Normal Mode (MPH)) down a few miles an hour (most of them down from 12ish to 10mph), but there was not change in shifting as the truck still waits until upwards of 16mph (as reported while logging, although speedo matches) to shift into 2nd. Is there some other table that is keeping the truck in 1st after the shift table says it should be shifting? The only other table that looked interesting for this is D0701 - Shift Pressure - Normal Mode (PSI). Thanks in advance for any help.

[2xls1]

Post your stock and modified bins.

[ColPaul]

Attached are the stock (04 Chevy 1500 4x2 LM7 12587603.bin) and modified (S10 12587603 1 Apr 21.bin). I downloaded the original from this forum.

[2xls1]

So you are not using a stock file as read from the vehicle you are modifying? What is the vehicle year and type you are working on?

[ColPaul]

Correct. The engine and transmission out of a donor 2003 Silverado 1500 were transplanted into a '91 S10 2 door pickup. I couldn't find the XDF for the '03 OS (12579405) so I used the OS from the same truck in '04 (12587603 universal donor OS).

[2xls1]

What is the rear gear ratio and tire size (XXX/XX/XX) on the S10? And are using a return fuel system on the S10 with vacuum referenced regulator on the fuel rail like the donor 03 Silverado used? (and the 04 didn't) Do you have a stock read from the 03 PCM before you flashed it with the 04 OS?

[2xls1]

Gear ratio was changed from 3.73 to 3.08 and tire size was changed from 29.21 to 29.59. Both of those changed the over all vehicle gearing higher but the shift and converter lockup tables were not scaled for the changes. I would still like to have the tire size in the format I posted. I will prepare a .bin file for you to try with those corrections, along with some other things that should be changes when running an 03 drive train with a 04 OS. It will be tomorrow before I'll have time to get it posted because I have to load it into a PCM then read it back out with Tunercat to get it back into .bin format.

[ColPaul]

My dad bought the truck for the guy that did the engine and transmission swap. I live several hours away so I'm waiting on a response from my dad on the tire size (H0101) and the fuel system questions. I did change the scaling on the tires and the gear ratio is a 3.08. We ran down the road and clocked mile marker and using GPS after making the gear ratio (H0103) and tire size (H0101) changes. Speedo and computer are very close to physical reality. You are correct that I didn't make any other adjustments for tires/gearing. I just did a compare on the two files in TunerPro (I'm sure you have already done that), but for reference below are the things I changed from stock:

- VATS disable
- VIN
- Gear ratio and VSS change
- Throttle cracker set to all zeros
- Zero'd out some park to drive enrichments trying to reduce the "jerk" when shifting into gear after partially warm
- Lowered some desired idle speeds
- Fan setting for custom application
- Lowered 1->2 shift speed in all partial throttle shift speed tables

The last one is the one that has me baffled as it is making no change in the shift speed for the 1->2 shift point.

We are in no hurry. I've coached my dad through downloading OS changes himself, but making the changes in the OS and advanced logging is a little beyond him at this point. I bought him an iPad app for logging that can do custom PIDs, but I don't think I could remotely direct him through setting the custom PID logging up.

2xls1, I really appreciate the help. In addition to getting the truck set up the way Dad wants, I'm trying to learn the interplay between all (well at least the ones I care about) the parameters and tables. If you want to tell me the changes to make, I'll make it in TunerPro and export the .bin.

[2xls1]

Idle speeds were raised, not lowered in S10 12587603 1 Apr 21.bin. I don't know why you would zero/disable the throttle cracker. Again, all the shift and lock up tables are still scaled for a vehicle with 3.73 gears and a 29.21 tire. That throws off all the shifting and converter lockup. In almost 20 years of tuning I have never changed drive enrichment tables.

[ColPaul]

I misremembered the idle speed change. You are correct that we set the lower limit to 600.

The truck was "running away" with no foot on the throttle in 2nd gear. It would get faster and faster, which require riding the brakes to stay at a slow speed in the subdivision in 2nd gear. Disabling the throttle cracker allowed the truck's minimum rpm to stay low with not applied throttle in 2nd gear.

The truck was running very rich (smell test) when warming up at idle in the garage. Dad wanted to lean it out so I changed he drive enrichment table.

I admit to being a newbie so please educate me. The XDF I am using with TunerPro shows most TCC and shift tables in MPH already. When logging from the ODB port, the computer reported speed matches the speed the truck is physically doing. Please don't take this as arguing with you. I'm trying to understand and learn from you. Thanks!

[2xls1]

For starters, the 04 12587603 file you started with was far from stock. That along with a 03 having a return fuel system and a 04 not having a return necessitating several injector tables to be set up different along with a few other differences between 03 and 04 are causing a lot of your problems. As for the shift and lock up tables, when you change either rear gear ratio or tire sizes, every table with mph axis need to be scaled by the % difference in what changed. For example changing from a 3.73 to a 3.08, every value in those tables need to be multiplied by 1.21. (3.73/3.08 = 1.21) Then if the tire size changes too those tales need to be scaled again either up or down by the % change. Scaling is not always X 1.xx. It can be X .xx depending on the change. This gets the vehicle shifting and converter locking up rpm wise as before the change. Commercial tuners like HP Tuners, Tunercat, EFI Live will do this for you when you make changes like those. Here is a completely stock 03 12587603 file with every other segment in the bin the same for you to compare to what you started with before you made the few changes you did.

Still waiting on the S10 actual tire size to complete a new file for you to try.

[ColPaul]

Thanks! Dad wrote back. The tires are 245/60R18. I'll look at the stock bin now.

[ColPaul]

I just realized that you also asked for the stock OS from the '03 PCM before I overwrote it with the 603.bin. Sorry for the delay. It's attached.

[ColPaul]

Dad had a chance to test some today. I continued lowering the 1->2 shift speed at low throttle position and we got a change. That lines up with what you are telling me about having to scale the shift tables. I changed the value to 9 mph and the truck shifted at 12 mph, which is where he wanted it to shift.

I also did some research on the pressure regulator. Dad confirmed that there is a pressure regulator on the left rail and it has a vacuum reference. Rock Auto shows that style with return fuel all the way through 2005. If I read Rock Auto correctly, 2006 changed to where the pressure was regulated in the tank.

[2xls1]

That is only on flex fuel. Non flex went returnless in 04. Look at the IFR table in the 04 bin. It is sloped. Return fuel systems use the same value in the entire IFR table. That is one reason the 04 bin is not correct for your 03 engine. I've said it before, while it is admirable that people are coming up with tuning solutions that are no cost, but the lack of XDFs for every OS is causing a lot of bad tunes, using wrong OS for the drive train hardware you have. You can't just throw any blue/green OS in a PCM and expect it to be correct for that engine without being able to look at what is correct.