I have a problem of which I have never had nor heard of. I have been tuning my built 355 TPI with a 730 ecm running 8d and a modified super AUJP V3 file. I have been working on it since August.

I was doing fine and got to where I was just working the small bugs out of the tune. The BLM's were between 126-130, always. I changed an area of the VE table and lowered the idle 100 RPM. Then I burned a chip (AM29FO4B?) and drove it, fine. I then bring up TunerPro to do some data logging and find that the BLM's have jumped to 148-160!

I do not understand this. The only part of the VE table I changed was the are under 1400RPM and from 40kpa to 80kpa. And this is what I get. I compared the bin to some of my previous bins and found no drastic changes. The injector constant was the same as well as the engine size. the VE table was the same where I had not touched it too. The car still idles and runs great though. I even have the remote switcher from Moates so I can switch bins on the fly. I have not done that yet as I thought of it as I parked the car to go class. So I will try it later.

What would cause it to do this?

 

Sounds like you took the VE table changes too far (real easy to do, I kow). Put the previous BIN back in and see if the BLMs come back to where they were. If they don't after a little driving (or resetting the computer by removing power to it), then you must have a newly discovered mechanical problem.

 

I am not sure what it is yet. I have the remote switcher so I was able to switch back bins on the way home. I keep all previous bins on the remote to allow me to compare and contrast. I switched to the old bin and had the same problem.

I also have a bin that is burnt in open loop only, it is exactly the same with the exeption of being open loop and and I multiplied all three VE tables by 1.10. Which would richen it up 10%. I clicked to this bin and found that the open loop was very rich where it should be, .800.

This is all very strange. Because I am wandering around the 150's BLM, so that should mean that I am .2-.25 lean. But the open loop bin is only 10% richer and it is rich as prementioned. What is going on?

 

Maybe your fuel filter just got dirty and the pressure dropped. Check the supply or the reg pressure, might be an answer there.

 

I had the exact same thing happen when we went to E10 around here. Everything was fine and dandy, and then all of the local gas stations went to E10 and my BLMs swung about 15-20 points lean across the board.

Teeleton

 

If you're using 10% Ethanol, you may want to re-set Stoich in your bin to 14.2-14.3

 

I am going out right now to change my fuel filter, than recheck fuel pressure.