7427 MAF 700R4 BIN Help

[halljam70]

Finished the 7747 to 7427 swap about a month ago (recommend) followed by installing a three wire vortec MAF and separate IAT sensor (HIGHLY RECOMMEND the 7427 / MAF setup for TBIs!!!!) Truck runs so much better than before but I've got two issues that I haven't been able to solve since swapping to the MAF bins.

1. 700R4 TCC: Since swapping to the MAF, the TCC in my 700R4 has not worked. Originally the $0D_MAF.xdf file I was using didn't have any TCC scalers or flags present. I copied and pasted some from another $0D non MAF mask, but it still hasn't worked. If I throw my old speed density chip back in the TCC works fine. In the 7427 pin out swaps I've read, I saw some debate on which pin to put the TCC on. I'll go back and look at my notes to see where it is now, but I know I moved it from the original pin I first had it on. But, again, with the speed density chip in, TCC locks up fine.

2. EGR: All the MAF masks I find already have the fan hack in them. I need the EGR to function in order to pass emissions. Disclaimer, I have not had the truck tested again since moving to the MAF setup. Tested it two weeks ago before the MAF swap and it failed due to HCs being above the state limit. Truck was running BLMs of 118 - 120 @ 2500 (2 minutes, part of Nevada's testing procedures) and idle BLMs were around 123. I plan on testing it again today once I put new plugs and plug wires in the truck. Truck does all in town driving and the AC plugs (R43TS) might be too cold.

Last question is for educational purposes. I see the differences between xdf files others have built in the forums. How do you edit/build them? I was using right click copy the copy xdf parameter to clip board, then open the xdf file I was using and pasted it in. Which hasn't worked.

Big thanks to Eagle Mark, Fast355, 93V8S10 and Dimented24x7 for all their TBI posts.

[halljam70]

Update for anyone that can use this. Truck past without having a working EGR. I modified the ADX file to MAF flow frequency table matched my three wire Vortec MAF sensor. I'll post the files shortly. Still working the TCC issue, but once I have that fixed I'll post the bin.

86 Chevy Silverado
PO rebuilt 305
416 heads
204 214 duration 112 LS flat tappet cam
stock TBI intake
stock over the plug exhaust manifolds (replacing them is the next project), factory y-pipe to 2.5" converter, 2.5 single in dual out flowmaster muffler
1997 three wire vortec MAF. Cadillac bonnet (2nd one, first one had an internal baffle), Spectra cone air filter attached directly to MAF
AC 43 plugs, Taylor pro wires

I will convert any future old car project to the 7427 computer, TBI, MAF set up. Drive-ability over a carb is night and day.

[notime2d8]

Hey, i am following this, as i haven't gotten my setup running right. I'm working on adding a VSS now. Glad to hear you got yours going!!

[halljam70]

what are you working on? I used a signal generator on My LT1 swapped Nova, but if I had to do it over again, I would use a 700R4 or 4L60E and converted the dash to an electronic speedometer. I converted my Silverado to a later model (91) Suburban dash due to the PO swapping in a 700R4 that didn't have the speedometer gear housing for the stock cable driven speedometer. Figured I had taken from this web site for the last couple of years, the least I could do is try to contribute.

[JeepsAndGuns]

I have been curious about the MAF mod. Seems all the people that I have seen online that have done the mod really like it.
I wonder if it can be done in conjunction with the MPFI mod (which I have) and if it would be a worthwhile venture or more possible tuning and diagnostic issues in the future.

[halljam70]

I've read threads that cover the 7427 w/ MPFI swap, but I haven't seen it used with a MAF. I'm trying to learn how to write in HEX so I can get the lockup on my 700R4 to work. The MAF / 7427 is lights out better than the 7747 I installed first. Granted, I wasn't that great with tuning, and I'm not using a wide band which may have caused some of the issues I had early on. The MAF setup allowed me to close the BLM range down to a couple of numbers either side of 128, where as in speed density mode, the truck would tend to run in the 112 - 115 range at idle, which is the reason she failed the first smog attempt.