HP Tuners does not require an XDF definition file. That need is built into HP Tuners. Tuner Pro RT, PCM Hammer (I think) and EFI Live (I think) need XDF files but my only actual experience is with Tuner Pro RT.

Believe me, I also have trouble keeping it all straight. And fortunately, I've yet to brick a PCM but I'm oddly looking forward to that life experience whenever it happens. Kinda' like losing your virginity and your first car accident all rolled into one. It'll be fun to see if I can recover from my bricking mistake.

Rick

 

Just figured I'd drop in and let people know that OBDX Pro has more of the VT's back in stock again. Right now they have the USB+Bluetooth versions with either black or clear cases ready to go. More of the USB only versions are expected by the end of the week.

 

I decided to take a look at the info in my PCM to see if I could change the rear end gear ratio. My car has a 3.08 and the tune was made for a 3.42 in anticipation of a gear swap. I have decided to not change the gear ratio and would like to change the PCM without needing to visit a tuner. I was able to gather some info with PCM hammer 014 and successfully saved a 1Mb bin file to my laptop with an OBDLink SX cable. The 4.8/4L60E and it's engine harness, PCM, TAC and pedal were all pulled from the same crashed 2003 GMC Yukon. I've installed Tuner Pro and have downloaded Bored Truck's git of XDF and bin files. The OS currently on my PCM is 12579405. Where to from here??

I have an 04 1Mb XDF for OS 12587603 that seemed to be a good place to start. Do I need to find a matching XDF for my 12579405 OS? When I look at the Speedometer, Axle Gear Ratio with this setup, I see a value of 4.687, not the 3.42 I was expecting to find there. I am able to change that 1 value to 3.08 and save it as a new bin file. Am I close here??

 

Is there an XDF for the 12579405 OS? If yes, then you'd just use Tuner Pro to open your bin with that XDF and make the change.

If not, then you're in a tough spot. Options include...

a) Hire a tuner to tweak the rear end ratio. Should only take a few minutes, might be cheap. But then you're still stuck in the HPT/EFIL world where you have to ask someone to make every little change.

b) Hire a tuner to copy your current tune into a 12587603 OS, using HPT/EFIL. Then your can continue from there using free software.

c) Find someone who is willing to make an XDF for your OS. Might be expensive (it's a ton of work), but would benefit everyone with the same OS.

d) Find someone who can make an XDF for just the rear ratio parameter. Basically any technically savvy person with HPT or EFIL and the right license load up your OS with that software, download the .bin file with PCM Hammer, then tweak that parameter in HPT/EFIL, flash it, download with PCMH again, and look at which bytes changed between the downloaded .bin files. That plus an existing unlocked XDF is enough information to make a tiny XDF that includes just that one parameter.

None of these options are great, I'll admit.

 

There is an XDF for 7603 that I have been using in my lab rat P59 PCM. All of the speedometer and gear ratio characteristics are there in the Tuner Pro RT "Speedo" tab within and around the "H0103" area, etc. Some simple math will be required to handle all aspects here of changing the gear ratio and speedometer pulses per mile.

I think this XDF should work but please use with caution because I don't have a vehicle that uses the Blue-Green connector P59 - this is one of my play PCM devices. I'd go to the junk yard and get a different "experimental PCM" if I was you in case this is on your daily driver vehicle and you brick its only PCM. Around here, it'd be a $38 expense for an extra PCM and everybody in our line of work needs a spare. Ok, I admit it, I'm a hoarder and have four extra. I can't pass one up in the junk yard especially when somebody else has done the work to make it an easy pick and I'm a fiend on Half Price Sale Days for these.

The system here on LS1 Tech won't let me attach this 7603 XDF file because it is not a supported file type. PM me and I will get it to you by email if you want it. You definitely don't want to edit your BIN with a mismatched XDF because it would likely cause a wrong calibration value to be generated.

Rick

 

Thanks for the replies guys, I have not found an XDF for OS 12579405 yet. I have another vehicle to drive, this PCM is in my 72 Nova. I don't mind picking up another spare PCM and harness to create a bench harness for testing/flashing if necessary. I'll PM B52Bombadier to see if I can get anywhere with his file.

 

I ended up needing to rebuild the bottom end of my 4.8, so I grabbed a 5.3 shortblock and rebuilt that instead. This allowed me to use the SSR5.3 OS 12587603 bin file, make a few modifications in TunerPro, and use PCMHammer to do a full write over my existing setup for the 4.8. I was able to set the gear ratio using my existing cable and PCMHammer. Thank you @PeteS160 @NSFW and @B52bombardier1

 

Glad to hear you were able to make it work!

 

Any time, Jim. Glad you got it running.

Rick

 

The car was dying off throttle coming up to a stop, I changed the desired idle speed in TunerPro in park and gear to 800 and that seemed to fix it's idle stumbling to death. I've since gone back in and lowered it to 750 and may continue to tweak it. The SSR tune feels more restrained than what I was used to with the 4.8, basically all idle lope is gone now, wouldn't even chirp tires under mild/medium acceleration from stop like before. It would just bog slightly and accelerate. I found and disabled the BTM setting and the wheels spin a little more like normal lol. Speedometer reads perfect from 0 up to around 45 during some local testing, I'm sure it will be much closer at freeway speeds than the 20mph it was off by before. There may be a more elegant way to stop my car from dying at stoplights, but I'm grateful to be able to make these changes without a trip to a tuner or $$$ for software.

 

I recently bought a 2005 Buick Rainier (same as Trailblazer) with the 5.3 LH6.The only thing I need to do to the calibration is change the fan from electro-mechanical to PWM. Can PCM Hammer and the related programs do that or should I stick with HP Tuners? Don't want to spend $100 licensing a VIN when I'm only making one small change.

Thanks.

 

FYI it's been a while since I attached any files here, but what I used to do for unsupported types was to create a zip (compressed) file using freeware 7 zip (Winzip also works) and then attach it. You may also just be able to change the extension from xdf to pdf. I tried the latter here with a small old XDF file I had. Let me know if it works, all you'd need to do is change the .pdf to .xdf after you download it.

 

A lot will depend on what wiring and relays are in your Rainier that can support PWM fans. There will also be air conditioning compressor needs here for fans. You need at least one of your e-fans to kick on the instant the AC compressor kicks on to keep compressor head pressures from going too high. Your compressor can't wait for a fan to turn on as the radiator temperature needs it.

But given the wiring, relays and how your AC is set up, yes, these programs can do the editing on your tune to avoid HP Tuners costs.

Rick

 

Since posting I've seen where Pete posted about the E40. In one post, he said they had no interest in it since it was a limited production PCM. In this thread he posted:
My confidence is low that the PCM Hammer can do what I want based upon his posts. There is no XDF file for it AFAIK.

As far as wiring for the fan, that is the least of my worries. I've posted details about mainly Mercedes high-watt fan connectors and 9.5mm terminals in another thread here. I have an S-class 20" 600 watt PWM controlled fan (built-in controller), a lot of large (4-6) gauge automotive wire, a mega fuse holder (planning on 60A) and new terminals for the Mercedes connector, so all I need to do is wire it up. That's futile of course if I cannot change the fan settings in the calibration.

As far as AC pressure, the fan(s) do not necessarily need to run when the compressor is on. As an example, cruising at 60 MPH there is sufficient airflow across the condenser to maintain proper line pressure. I have never cared for fan controllers that turn a fan on when the compressor is on. I have used a trinary switch in the past, but there is no need to do so on this truck since the PCM monitors line pressure. The 2005 Buick PCM is somewhat unique in that depending on how the pins are wired you can use the electro-mechanical fan (OEM truck), dual relays (GTO), or PWM fan (C6). It's very simple to do this in HPT. I would not mind running one of these with a corresponding harness in the LM4 into Dodge swap I'm doing now but don't need the added expense and hassle of wiring in a DBW throttle. Plus it already has a MK 8 2-speed fan.

 

I am planning on buying an OBDX Pro and using PCM Hammer. I really only want to set the Idle speed on my 4.8LS conversion and maye later do some minor tuning. There is a wealth of information (perhaps more than I can handle) available. I would appreciate it if anyone could post the basics of performing idle speed adjustment on a cable throttle body LS. Screen shots would be a plus.I am sorry if this has been posted, if so please point me to it. Thanks in advance.











LS conversion in

 

Hello,

To set idle speed using my preferred Tuner Pro RT tuning software, I look in the "Idle" area at "Table B4603". For all conditions of idle with an engine temperature above 90 degrees F, I set an RPM of 650. This allows a slightly higher RPM per the same table while the engine warms up.

Please see attached and this is for a 512k byte PCM.

Rick

 

I checked out the software and it looks promising. What hardware are you using to read and burn the prom? What interface can I use to log and reflash without removing the PCM?

 

BTW, I have an older Ostrich, not sure which version.

 

I have an OBDLink MX+ Bluetooth device for my hardware reading and writing. It plugs into a bench OBD2 wiring harness made from junk yard wiring supported by a three amp-capable, 13.8 volt DC power supply. I never, ever do PCM writing with the PCM installed in the vehicle due to the risks of the vehicle battery voltage falling below a critical level and leaving my PCM "bricked" and unable to be recovered. Or at least not recovered without difficulty.

My software for writing is either "LS Droid" or "PCM Hammer".

Rick

 

Thanks for the information. I just ordered an OBDX Pro and downloaded PCM Hammer. Any details on your bench setup to power up and read/write the PCM would be greatly appreciated.