The Vortec swap nightmare saga continues.................

[pmkls1]

I figured I would post a new thread rather than revive an old thread so that people don't have to sift through dozens of posts to get down to the nitty gritty. For those just tuning in the important info is; '89 Firebird Formula 5.0 L03 TBI w/700R4. Replaced 305 with used L31 shortblock and cylinder heads from different L31. New HV oil pump, GMPP single roller chain, 7qt deep sump oil pan, custom fabbed front half of exhaust from original 2" outlet manifolds to 3" midpipe and flowmaster muffler. Edelbrock Performer RPM 4bbl intake and Holley 4bbl-TBI adapter and reused ALL other hardware from the 305. Base fuel pressure ~30psi due to idiot mechanic (me) installing way too much of a fuel pump long time ago. Later replaced 1228746 ECM with 16197427 PCM. So, in the last episode I realized that I had installed the incorrect dizzy gear and that the RPM signal to PCM was fluctuating and determined that it was time for a new dizzy.......

Fast forward to the present and I have made progress and also determined that I am destined to rebuild this car piece-by-piece wether I want to or not. I finally got a new GM distributor and also a new Accel cap & rotor kit and installed them. The GM dizzy comes with a cap and rotor installed, but I simply prefer the Accel parts as they are more robust and just as affordable at ~$25 for the set. I trimmed and re-routed the existing Accel 8mm spiral-core plug wires as they are in ok shape and I found a spare set of terminals for the dizzy end of the wires in the basement. I also replaced the low-mileage plugs as there was some fouling from a rapidly progresing misfire. After all said repairs were made I restarted the car and found that I had cured one ailment only to discover another. The old dizzy was having issues that I believe to be rooted in the aftermarket ICM. The new dizzy did clear up a lot of isues and also required a remap of the ignition timing after trial and error showed that the old map parformed very differently with a new and "proper" dizzy was installed.

The problem was, however, that upon fixing one issue the next issue only stood-out even more. Cutting to the chase, I'll leave out the boring bits and get right to the isue. After some driving and tuning, I discovered the MAP sensor to be going bad. I always monitor it in my logs and quickly noticed that it would not register numerically lower than 38kpa anymore. I instantly recognized this as a problem knowing full-well that at idle in park it usually reads closer to 30 and while decelerating it will drop into the teens under the right circumstances. I quickly sourced a known-good used late model MAP sensor and connector and installed it directly to the TBI unit with a short section of hose. Upon startup I knew that the issue was resolved before connecting the laptop. That led, however, to yet another issue..........

This time the issue is mostly programming related. I had been logging and using the VE correction spreadsheet as the MAP sennsor was going bad (unknowingly of course) and had been tuning IN a terrible deadspot. Once I had replaced the MAP sensor, the deadspot only became more pronounced and it took a little watching to spot the issue. So, to correct the issue enough to drive the car I had to throw in the old VE tables and start from there. The car drives pretty good now, but there seems to be something wrong with my DE and DFCO settings. What is happening is that while decelerating the BLM will continue to drop until it switches into DFCO. Then, upon exiting DFCO, the current BLM cell will be all jacked-up for lack of a better term and the car will lean out to the point of stuttering until the BLM counts back up into the proper range. I can bypass the deadspot by nailing the throttle and entering PE mode, but this is obviously not a solution.

So, I will attach my latest BIN and XDL for any to take a peek at. The VE tables are way off at this point because I reverted back to some starter tables after replacing the MAP sensor and using the VE correction spreadsheed will make the problem worse due to the current issue. Using these crude VE tables makes the car drive the best at the moment until I fix the DE/DFCO issue so take note of that while looking things over. The spark tables are pretty close at the moment and the knock counts are due to several different verified mechanical noises (non internal-engine damage related noises) at the moment so the knock retard has been disabled temporarily. I think there's more, but gotta go for now. Thanks in advance for taking the time to read through this post and reply.

EDIT: All of my recent log files are too large to upload so I will need to make a shorter drive and upload that file.