Tuning the Monster...I hope

[KennyChapman]

First of all, thanks everyone for being so cool and helpful! So I guess I did my project backwards. As an oldschool car guy I built the motor for my 1999 c2500 Suburban first and then hoped it would run on it's original "black box" ECU. The engine is a 496 stroker BBC With custom intake and heads. OEM injectors on a not so OEM fuel system. Anyhow, It looks like my best bet for this thing is to do the Ol' 0411 swap. I already PM'd Lextech, but would love any help that can be offered with a base tune or at least a starting point for one. I am on overload with all the data that is here and it seems that there is little about this particular build of mine. At least I can't seem to find it when searching the forum. I ordered and received a GT dongle from OBDXpro last week and hope to use PCMhammer and Tuner pro for this tuning. Thanks in advance for any help you can send my way.

[dave w]

[KennyChapman]

Thanks for the Welcome! So, progress report. I made it out to the local "you pull it" Junkyard today and picked out two 12200411 PCMs with connectors (In case I ruin one) for $40. I cleaned the gunk off the outside of them and soldered up a bench harness. After some fooling around with drivers and rebooting my PC I got the OBDXpro GT to finally work and was able to save my first BIN file, which I am attaching, in case anyone cares. Now on to find an XDF for it...

[KennyChapman]

I made a lot of progress on this. I completed the swap and once I disabled VATS and changed the VIN it started up. Today I am working on wiring in the 4 PRNDL wires and trying to get the TPS to have a more accurate response. My Throttle body is custom fab by me in order to use the OEM TPS on a dominator intake. I am going to post in this thread the steps/tune I used to get this swap to work on my 8.1 L 496 BBC engine once I have perfected the tune.

[ralmo94]

Today I am working on wiring in the 4 PRNDL wires

I believe I you don't have to wire those in if you change something in the tune, if I remember correctly, in HP Tuners, you would change PRNDL drop down menu to "none", and it will use the range sensor on the transmission.

[KennyChapman]

To get the VE dialed in, you need to fail the MAF sensor so it runs speed density.
Did you adjust the cylinder volume size?
Are your injector settings correct for injectors being used? That's where to start. (From the other thread.)

I think I am getting my butt kicked by this part. I really have no idea what I am doing but I have spent Probably 40 hrs over the last few weeks reading stuff and trying to understand tuning. I did disable MAF. Cylinder size is correct. But I have no idea what to set for fuel injectors. I found some stock flow data as I am using the stock injectors, but I was not able to read my original PCM and have no frame of reference to start from with; Injector voltage correction, Min.Injector pulse, Injector Pulse Width voltage adj., default Injector Pulse Width. The swapped in PCM was from a 5.7L engine and I am way up at 8.1L but still using stock 7.4L vortec L29 injectors.

ralmo94, if you have the ability to look up any of the stock param's on your vehicle( I believe you have the same as mine when it was stock) That would be so awesome.

I didn't see your post until i had already soldered up the harness with the 4 transmission wires. Hardware is super easy for me so I had no trouble with that. I'll post some pictures later.