Fuel Pressure & Timing

**ex-x-fire** · 03-21-11, 06:50 PM

Try raising the fuel pressure 1/2 psi then test, keep doing that till you get the best perfomance.
Do the same with the timing, increasing it 2 degrees til you get the best performance, you might have to use a higher octane of fuel.
Disconnect the vacuum hose to the air cleaner flap, you want max air flow there.

**ParisTNDude** · 03-28-11, 09:34 PM

Originally Posted by ex-x-fire

Try raising the fuel pressure 1/2 psi then test, keep doing that till you get the best perfomance.
Do the same with the timing, increasing it 2 degrees til you get the best performance, you might have to use a higher octane of fuel.
Disconnect the vacuum hose to the air cleaner flap, you want max air flow there.

I searched but couldn't find the fuel recommendations on the Cross Fire engine...what is it? Does the computer not control the timing (I'm used to the fully ECU engine control) and is the timing set with timing light as in days of yore? How would you raise the fuel pressure? These are good no cost tips...thanks.

**xfirez51** · 04-21-11, 09:14 PM

Originally Posted by ParisTNDude

I searched but couldn't find the fuel recommendations on the Cross Fire engine...what is it? Does the computer not control the timing (I'm used to the fully ECU engine control) and is the timing set with timing light as in days of yore? How would you raise the fuel pressure? These are good no cost tips...thanks."

ParisTNDude,
The recommended FP for a stock Xfire was given as 10 to 13 psi. The stock system does not allow changing FP but the regulator in the rear TB can be modified so that it is adjustable. Changing FP has an effect on the calibration. The ECM does control timing, but Initial SA is set at the crank w a timing light. It is set after disconnecting the ECM so that only the distributor is controlling timing. I usually set initial timing at 10d.
One issue to be aware of is a slipping outer ring on the damper. That makes setting correct timing problematic.