I am having tuning issues since my 450 install but its a rich concern. But tuning my High octane map has helped a lot.

 

As long as the siphon in the tank was drilled to 9/64's, a rewire that maintains the factory dual voltage power supply system for the pump was done, the stock regulator can handle the 450 no problem.

 

I did none of these mods in my car. Is this why im having rich issues?

 

I have an OMNI 4 bar MAP sensor that was on there when I bought the car two years ago so would that make it an "old one"? And since it basically just reads pressure could that even be causing my problems?

I have also not done these to my car. But wouldn't not drilling out the siphon cause a bottleneck essentially and cause you to get less fuel than needed? I guess I could see it causing more pressure in the system since there is more of a restriction and the 450 can't produce the flow that it wants to. Could not doing the rewire cause my injector problems?

 

I was having rich issues during wot but I got them in check with Afr Map tuning. Im seeing 12-11.8 to red line sometimes 12.4 depending on weather.

I did a fuel pressure test on my car and I got 40 ish (broken guage) I think idle is 43 base.

My fuel trims are -0

 

Probably.


When running speed density, the ECU relies solely on that sensor to determine load. Load and RPM then determine timing advance and fueling. So, yes, it could very well be the issue.


The siphon is in the return line. It siphons fuel from the passenger side of the tank. It already is a bottle neck. With the higher flow of 450 pump, it is generally needed to drill it out to get fuel pressure under control. By doing the proper rewire that maintains the factory hi/lo voltage, and drilling the siphon to 9/64's in my car, it required no changes to fueling in the tune.

 

Well I'll look around for a new sensor and give that a try and hopefully that's what is causing my issues. I'll probably go ahead and do the fuel side of things as well just so I know I have one more thing in order. Thanks again man.

 

Thank you for another quality reply.

 

Fuel Pressure is spot on. It turned out to be that we were using a 9417 variant ROM and it was responding bad so we switched to a 9653 ROM and she seems to be doing just fine now.

 

Base pressure is actually 43.5psi...

 

lol this guy...

 

You always set (or measure) fuel pressure using base pressure (no vac line attached), because depending on cams and other things, manifold vacuum could be different, resulting in different fuel pressures with the vac line attached.


Some peoples kids...

 

What you actually DO is set the base pressure, measure the vacuum, take it away from base pressure...............that's what you see on the gauge with the engine running.

That way you've got the base pressure ACROSS the injector at all times.....it should be constant and should never change.

That's how you know when your FPR is being outflowed which it always is with a bigger pump.
Then the engine leans out under high load because the fuel trims have changed under low load.

 

I'm not here to argue about your other mechanical argument but any tuner worth their beans turns off fuel trims affecting WOT fueling.

 

Even if they weren't turned off, it certainly wouldn't cause IDC to go to zero. Even if a trim was -25%, if your injector on time is 8ms, that's only going to take it down to 6ms...