The service manual states anything over 54 psi is to much fuel pressure.

I'm running an aftermarket fuel system and the pressure is around 60 psi. Does anyone know if this is to much for the stock injectors?

My issue is in closed loop it is running rich and it will hardly stay at idle. If I unhook the brake booster line to give the engine more vacuum it idles fine.

 

So install a regulator, and turn the pressure back down to where it should be. According to theory, once in closed loop, the O2 sensors should clue in the PCM that it's running rich, and the PCM should then pull fuel, to keep the mixture where it should be.

 

Sorry the issue is in open loop not closed loop.

thanks for the info. I’m wanting to get options on if the issue is the pressure before buying an adjustable regular.

 

I agree. V10 is a great motor but is needs to be run within its specifications. The computer in them only has a certain range that it can accommodate. Excess fuel pressure will cause lots of issues. You should be around 45 psi so either go back to stock or put in a regulator.

 

Of course it is going to run rich in open loop. It's running from tables stored in the PCM, with no adaptive learning applied, For X condition, pulse the injector Y microseconds. But, it expects stock fuel pressure, with higher pressure, you are going to get more fuel for the same pulse width. Regulator knocking pressure back to stock values will fix that.

 

Ok so I ordered an adjustable fuel regulator and gauge. I understand how to install it and set the pressure but the regulator has a vacuum/boost port that will change the pressure based on manifold vacuum or boost. I'm going to assume I don't need to hook this up because the stock PCM already monitors the manifold pressure and O2 sensors and will adjust the injector based on the programming. So I just need to set the base pressure to 45psi and I'm done, correct?

Thanks

 

Set base pressure to whatever the spec is, and yep, you are all set.