Ok... so I got this in the mail a few days ago...
For those who don't know, it's a specialty tool that allows you to adjust the fuel pressure regulator installed in the Rochester 300 and 400 TBIs. You could order from GM an adjustable fuel pressure regulator for the Fiero's 2.5, which you could only get from GM. The 82 and 84 Corvette and 82-83 TransAm came with this adjustable fuel pressure regulator on the second (rear) 400 TBI unit... you only need to knock out a metal plug before you can get to the connector. It allows you to then adjust the FPR in real time while the car is running.
I had to rob a bank and kidnap a child in order to find one, but I got one.
I didn't really know what I was doing, but Paul Romsky's ALDL reader consistently is saying that my BLM was 128 and I had an INT value of like -80 and -90 almost the entire time, except for a few instances where it would go down to a -27. My O2 sensor was constantly reading a RICH condition.
So anyway, I dialed it back (once I figured out which way turning it would make the FPR decrease... or whatever would make it have less fuel). And it now runs quite a bit better.
I now get a BLM of 115 with a -13 modifier, and INT values consistently showing anything from -7 to -49. Still seems like it's running a little bit rich, but it's running so much better. I ran well before, just didn't have as much pep I suppose. It feels even quicker now.
I really wish I knew what I was doing though... can anyone explain BLM and INT? Best I can tell is that BLM is the Block Line Modifier... I don't know the difference between a BLM of 115 or 128. The INT is the value that adjusts every time the PID goes around. The fact that it's negative means (to me at least) that it's trying to reduce the amount of fuel.
Is there a quick primer or something I can read up that explains exactly what the ideal BLM and where I should see INT at, even when it's just idling?
Still waiting for the new temperature sensors to come in the mail, and then I'll be able to see the temperature again. Apparently my MAP sensor was also failing...
I'm also getting an Idle Air Control error... though idle seems perfectly fine... but maybe it just needs to be adjusted, or it's an old error. Idle seems to sit calmly at 975 rpms when it's warmed up, and it doesn't fluctuate or anything.
