Hey guys, while accelerating part throttle from stop signs to 60mph, I noticed some lean popping. When I hooked my computer up, the BLMs were in the high 130s and low 140s. I replaced the fuel filter and increased the fuel. I nailed it down to 127s to 129s across the board and got rid of the lean pop. That was a week ago. Now, after driving again, the lean pop has returned. If I datalog, it shows BLMs in the 130s again. This is in the 40-70kpa range, 1600 to 2800 RPMS. The fuel pump is a walbro 255lph, less than 1.5yrs old. The injectors are bosch IIIs, less than 10 months old. Fuel filter is brand new obviously. They're not already filling the tanks with winter gas, are they?

By the way, when I nailed the BLMs down, I was datalogging well after the engine reached running temp. The thermostat was open and the pri fan kicked on (it's set to kick on at 192F). I didn't check the IAT, could the IAT tables be skewed? I have never adjusted them. What's the sign of a fuel pressure reg failing?

 

Almost forgot, it's a 730 ECM with $8D mask. Speed density retrofitted on an '89 L98.