[CH75TA]

So I'm new here I have a blow thru 301 turbo with 670 heads, ram air 4 cam, with a narrowed torker 2 with fitech fuel injection and I need help.
It will start and run for about 45 seconds and pop back through the throttle body and die, when it dies that the fuel pressure jumps to 60 psi from 58. It runs rich but does the lean pop, timing is locked at 22* what do you all think.
Thanks to anyone who can help.

[JLMounce]

Most common reason with the FiTech for such a situation is a vacuum leak, followed by timing issues.

The 2 psi jump in fuel pressure from 58 to 60 is fairly inconsequential, especially considering a backfire state.

What fuel system are you running?
What model FiTech?
What ignition system is being run? Is the FiTech controlling timing at all?

This combination has a lot going on. A RA4 cam in a 301t with a 72cc head is a massive cam. Large enough that even the cam 4 profile in the FiTech may not be lean enough at idle to cope.

Have you been able to run the engine long enough to get an idea of what type of vacuum the engine pulls? The FiTech works quite well down to about 7-8” Hg. Below that it requires some heavy handed tuning to get it to run right. There are people that have these running on combinations making as low as 2-3” of vacuum, but the amount of work necessary to do so puts you in a position that running a Holley HP, Haltech 950 or Fueltech 600 would have been easier.

What occurs on these systems when there is a very large cam in use is that idle fueling can be rich enough that raw fuel is passing through the combustion chamber in the overlap duration and showing the oxygen sensor raw fuel. The ecu reads this as a rich condition and pulls fuel, creating an oscillating rich/lean condition. It’s possible this oscillation could grow large enough to cause a lean backfire. If you’re not on map 4 to begin with, try that first. If you’re already using map 4, you’re going to need to break out the laptop, load the tune in procal and edit the VE table to further reduce idle fueling.

[CH75TA]

Jason thanks for the info, it makes perfect sense about the overlap. I'm not sure what map 4 is. I was going to put a carb on it but got this deal on the fitech, I'm seriously thinking about putting my already built blow thru holley on it and put the fitech on my 80 301 turbo with a comp 260 cam. The fitech system is the 600 power adder.

[JLMounce]

In your initial setup it will ask you for some basic information to setup the initial fuel map. If you haven’t done that, it’s where I would start.

I get the feeling this unit may have been used on a different engine before, or did you buy it as a new in box?

In the handheld there is an option for initial setup. You’ll input your cubic inches, select a cam profile 1-4, select what type of ignition setup is being run, and a few other items. Here is a video with instructions.

https://fitechefi.com/initial-setup-tech-tuesdays-ep3/

If the unit was ever run on another vehicle you need to reset learn. Here’s instructions on doing that.

https://fitechefi.com/fitech-efi-bas...-instructions/

[CH75TA]

Thanks again, it was on another 301 turbo at TTA Performance. Thanks for the links, that's what I'll be doing tomorrow. I'll let you know how it goes, I live 15 minutes from the Trans Am Nationals and what this car there.