View Full Version : Fuel Tuning FAQ

08-24-2010, 12:53 AM

Q: I raised my boost pressure, now the car stops and shakes when I get the boost going faster

A: You have found fuel cut. Fuel will stop being pumped into the engine if the Toyota ECU detects 12 psi on ST165/ST185, and 17 psi on ST185RC/ST205 models. The Toyota ECU is set to activate fuel cut if it detects 4.4 volts from the Turbo pressure sensor. The Turbo Pressure Sensor is reading boost from your intake manifold and puts out 4.4 volts (roughly) at a certain boost level. First, if you haven't purchased/installed a boost gauge, please do so. This is vital to the tuning you are about to do. Second, to disable fuel cut we just have to stop the computer from seeing 4.4 volts under any conditions. Go the MODS section to find out how.

Q: I want to install a Supra TT fuel pump, is it hard?

A: No, it bolts right in. If you can replace your fuel pump, then you can certainly install a Supra TT. Being that it's a Toyota piece, it bolts right in.

Q: Can I put in a Supra Fuel Pressure Regulator for high performance?

A: It may be possible, but the 2 are completely different in size and mounting. A lot of custom work would be required, for little or no gain. If you are daring enough here are the numbers:

ST185 FPR ND# 0970 83280 74070

JZA80 FPR ND# 2110 23280 46030

Q: I'm searching for replacement upgrade injectors. What type do we have?

A: See the fuel tuning page. Here is a quick rundown:

ST165 Low Impedance, Top Feed, Nippondenso style (440cc)

ST185 Low Impedance, Side Feed, Nippondenso style (440cc)

ST205 Low Impedance, Side Feed, Nippondenso style (540cc)