Excessive Cranking to start...Fuel system???

[ssx]

Hi everybody...hope this is not too basic a question, but I am new to the world of fuel injection and tuning. My 67' Nova currently has an 2004 LS6 run by a FAST Xfi and FAST Xim. The fuel system is a stock 67' Nova tank with and external Walbro 255 pump and corvette regulator. When I go to start my car I have to crank it about 7-10 times for it to start. A lot of times I crank it 5 or 6 times, wait, then crank another 3 or 4 times then it starts. The shop that did the install said because the Walbro is a external gravity feed pump the problem persists? I have not heard of anyone else having this sort of problem? Shouldn't the fuel stay "primed" in the system? I would love a Rick's tank or something, but at the moment I am so far over budget on this build, I can't afford it. Any ideas? Can I get a fuel pump that is not gravity feed? Could it be the tune? Any other ideas? Help...

[parsonsj]

ssx, It is most likely your tune. Can you get a gauge on your fuel rail? See if there is fuel pressure? That's the place to start. If you have fuel pressure, then we need to see what your voltage is during the cranking interval. If you get below 10V, the ECU resets, and that can cause what you're seeing. If that checks out, then we need to look at your cold cranking fuel along with your spark advance during cranking.

Hope that gets you started.

jp

[MrForce]

All of the above, plus look at increasing fuel pump prime time and perhaps adding a check valve on the outlet side of the pump. Make sure you have good fuel pressure before you chase the tune.

Rob

[ssx]

Thanks John and Rob...I was worried about it being the tune. I have nobody around that is familiar with the Fast setup. The shop that did the swap was learning, but still nowhere near was I would call expert on it. I may have to look into a mail order tune. The system was upgraded to the 2.0 which is supposed to self learn and tune itself...or so I thought???

[parsonsj]

The self learning bit of the XFI 2.0 is not going to address cold start, which is what you're dealing with. You need to get back to basic principles and figure out where you stand with cranking fuel pressure and voltage, and work from there.

I said it, Rob said it, now let me emphasize it again: Make sure you have good fuel pressure during cranking and good voltage before you chase the tune.

[ssx]

Okay, thanks again for the reply John. I will order a gauge to check fuel pressure and check voltage during cranking...then I will take it from there!

[parsonsj]

Good luck and let us know what you find out!