Hey guys,
I have a 99 silverado 5.3 with a STS turbo system, methanol injection, and electronic boost controller. Mods made at time of install: 42# injectors, 2 bar Map sensor, descreened and machined out MAF, Bosch iridium plugs, Taylor wires, small stall converter,
aero turbine no tail pipe, still running MAF. I think thats all! Anywho, when I tuned it earlier this spring,(before EFI University), It was running hard ;11Psi boost, Methanol, Afr mid 12's, occcasional KR of 1 to 2 deg., putting down 404RWHP(Mustang), 138,000 miles.
Just recently noticed It's not pulling as hard . I've checked everything mechanical I can think of; cats are good, O2s new, no leaks(gauge reads 11Psi still), no trans slipping( input and output speed not different enough to worry .5MPH), verified dyno calibration. when i run it on the dyno it shows 342 RWHP. Loggin shows nothing out of range or abnormal. Methanol works, although dilution might contribute, no noticable blowby or vacuum leaks. the truck runs great just not as hard.
Is it possible that the PCM has adapted? I will be switching to custom OS and SD in the near future. (couldn't make it work on my last project)
Any thought would be greatly appreciated!
One more thing: To all the guys at EFI Live keep up the superior work, Excellent product.
Eric