Fueling Problem

[blitzkreig]

guys, hope someone can shed some light on my problem.

engine specs: RB26 (Stock)

GT40R BB Turbo

Power FC D-Jetro with ID 725cc injectors

problem is that, no matter the amt of inj duty% I input , the A/F ratio remains 12.2 - 12.3 from 7000 - 7600 rpm. low to med loads are ok.

car is running 15psi.

I am thinking maybe a vacum leak, but the car idles @ 850 rpm steady. On WOT, I am seeing a pim voltage of 3.5v.

what you guys think?

[The Mafia]

Fuel pump maxed out, or fuel delivery issue.

[blitzkreig]

Fuel pump maxed out, or fuel delivery issue.

fuel pump is nismo. also have hks fuel rail, nismo pressure regulator and -6an lines.

[Guilt-Toy]

when was the last time you changed the fuel filter?

[scotty nm35]

What base fuel pressure?

[blitzkreig]

fuel filter was changed when upgrade took place. base fuel pressure with hose off is 45 psi.

[scotty nm35]

Have you measured the voltage at the pump?

Are the 725 ID's going to be big enough?

[Guilt-Toy]

ID injectors, the best high imp injectors on the market. (IMO no flaming please)

How did you wire these babys up?

Just wondering.. but....

You just installed them in the stockers place right?

Do me a favour, measure the resistance across the stock GTR injector you took out and then those ID injectors you put in.

Can you see a problem there?

[blitzkreig]

ID injectors, the best high imp injectors on the market. (IMO no flaming please)

How did you wire these babys up?

Just wondering.. but....

You just installed them in the stockers place right?

Do me a favour, measure the resistance across the stock GTR injector you took out and then those ID injectors you put in.

Can you see a problem there?

bypass the resistor box , since they are high impedence. the stock inj. are low impedence.

[DVS JEZ]

What power is it making.

Have u checked fuel pressure.

Have u checked the voltage at the fuel pump. If u havent already u should wire in a relay with battery voltage as the standard system is voltage regulated

[The Mafia]

You've really given us f**k all to work with.

We need more information, like power, all mods, not just a half assed post leaving us guessing.

For all we know this engine could be fitted to a monster truck.

[blue_vl_t]

As already mentioned, fuel pump voltage sounds like the issue, r32 gtr run 11.5 v before running a hard wire and relay

[Guilt-Toy]

bypass the resistor box , since they are high impedence. the stock inj. are low impedence.

good

[blitzkreig]

You've really given us f**k all to work with.

We need more information, like power, all mods, not just a half assed post leaving us guessing.

For all we know this engine could be fitted to a monster truck.

Car is being street tune. as for mods, read the thread again. if it really matters, car is making about 350 whp. ran it against a r33 with 400whp (dyno tune), and was right behind his bumper.

[blitzkreig]

Have you measured the voltage at the pump?

Are the 725 ID's going to be big enough?

gonna get a fuel pressure gauge and check for pressure drop. did not really suspected this, since everything is new (nismo pump, nismo regulator, ID Inj., fuel rail, fuel filter, turbo etc.)

[scotty nm35]

I just thought with a GT40 you would need a fair bit of flow, I have hit over 80% on the 1000's with a GTX3071 on eflex.

You may be reaching the limits of your pump, depending how you have it mounted and if the sock is close to the bottom of the tank? I found too with more torque, more fuel is required for similar power output.

[blitzkreig]

got the fuel problem sorted out. ran a relay to the pump and now the pump has all the voltage it needs. went fom 12.2 to 10.5 a/f.

[The Mafia]

So I was right all along.

I had this exact problem but you were slowly feeding us scraps with the mods, car type, etc then smartassed me about "reading your scaps" so I gave up helping.

Anyway, glad its solved. Next time you post a thread, post absolutely everything about the car.

Not - "fuel pump maxed out"

"can't be, it's a nismo"

Well, it was, and yes, it was maxed out. Due to low voltage.