backfire

[lbheart]

hi all,

I have put an ls2 with ls3 square port head and a cam in my Nissan patrol. the engine is brand new and never been started before.
i am using an ls1 pcm and efilive v1.2

when i tuen the engine over it goes to start but won't run and i am getting backfiring back through the intake.
what could this be? timing? tune?

could low fuel pressure do it? i am using brand new fuel pump i ordered however i put a gauge on the fuel rail and it is only showing 40 PSI pressure

any ideas would be greatly appreciated.


thank you very much in advance.

[lbheart]

is there anyway to convert and e40 or ls2 tune for the ls1 pcm?

which tune should I use I noticed I can download different tunes from the file depot

im in aus by the way.

I just need to get this up and running, it is going to be dynotuned.

[joecar]

Do you know if the LS2 engine's crank/cam reluctors are 24x/1x or 58x/4x...?

( remove the CKP sensor and peek inside...
if you see a single reluctor wheel with evenly spaced teeth then it's a 58x;
if you see dual reluctor wheels (which appear to be the inverse of each other) with unevenly spaced teeth then it's a 24x;
)

Is it an early (24x/1x) or later LS2 (58x/4x)...?

40 psi rail pressure is too low... it should be 58 psi.

[lbheart]

Sorry I should of mentioned.
Im using the conversion box. German name starts with l

[lbheart]

Yes I have a feeling the guy I got the fuel pump off ordered the wrong one

[joecar]

And you need the correct FPR (58 psi with reference hose removed).

[joecar]

Sorry I should of mentioned.
Im using the conversion box. German name starts with lYou mean the LPE 58x/4x -> 24x/1x converter

( LPE = Lingenfelter Performance Engineering )

[lbheart]

You mean the LPE 58x/4x -> 24x/1x converter


( LPE = Lingenfelter Performance Engineering )

Yes that is the one I am using.

I modified my fuel tank (welded plates in the top) so they take the self regulating commodore pump so I only need one fuel line up the the engine bay. I must have the wrong ones because im only getting 40 psi instead of 58

[lbheart]

I have two fuel tanks each with their own delphi fuel pod and independent fuel line up to the engine bay

[lbheart]

Maybe there is a way to modify the ones I gave to pump at the correct pressure. The way it works is the fuel is pumped in a loop down at the fuel tank and this loop is at pressure so u T off that loop to get fuel at pressure to goto your fuel rail

[joecar]

The pump module has an FPR (with its reference open)... you may be able to change this.

[5.7ute]

Is there a check valve in your fuel lines to prevent reverse flow in the unused tank?

[lbheart]

Yes there is a valve so I can switch between fuel tanks. Open one way for main and another for aux