Been awhile since I lurked here or posted on this thread (my $200 junk yard '87 tranny for ECM compatibility quit shifting to OD, so the truck has been sitting), but reading the recent posts, I am surprised that RF hasn't mentioned the other option of the
Flash EBL, which replaces the PROM with flash memory (think zip drives or digital camera memory), allowing you to flash updated programs to the ECM instead of having chips burned. RF and I both use the Flash EBL ECM and I find it to be a simple and powerful upgrade that I consider well worth the price given the steep learning curve to program and/or burn PROMS (or the hassle and on-going expense of data logging and sending files to someone who burns chips until you get it right).
The Flash EBL also comes with an optimization routine that simply data logs and suggests a new program based on the data it gets and that takes about 1 second to flash to your ECM. After 5 or 6 optimizations, you won't believe how well your truck runs (or the mileage you get - my 82/85/87 C20 long bed was up over 30% compared to the carb!).
My truck ran real rich after I got my TBI conversion done using stock parts and ECM from an 87 suburban C10 and I attributed it to excessive fuel pressure, which the Flash EBL compensates for (simple spreadsheet table you load with actual fuel pressures when first starting the program). I also run early non-vortec heads and an older RV cam and the Flash EBL still makes this "mutt" of 20+ year old parts run as reliably and well as something built in the last five to ten tears (really low emission rates at my last smog test too!).
The Flash EBL also helps with disabling codes or modifying simple things in the program. For example, I had problems with intermittent ESC codes being set and I re-programmed (
i.e., disabled) the timing retard using TunerPro and flashed the modified program to my Flash EBL ECM until I got around to finding the bad ground in the harness. After I fixed the wiring, it was simple to re-enable the timing retard for ESC and re-flash the ECM back to stock specs. I am sure this approach would work similarly for the no EGR issue Pancake has - and I bet it would do a good job compensating the fuel delivery program for decent fuel mileage even without the EGR (I have no date to prove this, but this my guess).
Finally, the EBL Flash has a number of add-on programming enhancements not normally found in the stock ECM -see their web-site to see these. Downside is cost - $350 for the DIY model and you need a laptop to run the TunerPro and Flash EBL software (I use a 10 year old P3 running Windows 98 with great success).
DISCLAIMER: I have absolutely NO vested interest in Dynamic EFI - I bought and paid for my Flash EBL at full retail with my own $$ and am simply a satisfied customer (and happy camper with the outcome). Frankly, it was one of the best mods/decisions I made when I did my TBI swap.
Sorry for the "sales pitch", but I wanted to let others know that there are some nice (albeit kinda costly) alternatives to getting chips burned that also open up other possibilities. Good luck with your swaps.
Mark