Sikocivic

I have a D16a6 built turbo motor.(10-1 pistons and Eagle rods and more) I have been doing some tuning on it and I can't get the fuel low enough in high vac and idle. It only goes down to 1.08 or 1% duty cycle.(AFR in the 9s) I am only running at 55% duty cycle at 15lbs of boost. My thought was to pull out the 450 injectors and go with some 390 DSMs. That would allow me to lean it out at idle and high vac. They would be working harder while boosting but they should be able to handle it.

Would I have to start all over again on my tune or will TurboEdit compensate when I select the 390 size in the program? I know I will need to do more tuning, but will changing the injector size throw the current tune all out of wack?

Or is there a way to lean out the 450s at idle and high vac?

Foowee

Try upping your fuel pressure. I know this seems counter intuitive. Just try it and tell me what happens.

Sikocivic

Upping the fuel pressure would give me more fuel not less. Besides, I don't have an adjustable fuel pressure regulator anymore.

Foowee

Sikocivic

Anybody else have any ideas?

Chris Harris

Something is wrong if you need to go lower than 1.08ms on DSM450cc...ever TurboEdit car I have tuned with 450cc needs about 1.80-2.20 msec of fuel in the idle area.

I bet your fuel pressure is way too high...do you have a gauge on the rail?

Sikocivic

I will check the fuel pressure. I know it should be 35-40 psi at an idle.

Would this also cause the motor to go pig rich when I am at high RPM and just let off the throttle?

Sikocivic

OK, the fuel pressure is 58psi and only drops to 55psi when I disconnect the vacuum line. I swapped in a different regulator but it still reads the same. When I pinch the return line with a clamp the pressure shoots way up and then drops back to 55psi when I release the clamp.

What else would cause the fuel pressure to be so high?