Fitech Fuel Injection for MK4 Roadster

[jhamburg54]

I purchased a Fitech Fuel Injection with a complete command center kit (part number #40004). I mounted the command center in the engine bay. The engine bay gets really hot. I have been told by two mechanics that I should put an internal fuel pump in the fuel tank instead of the command center mounted in the engine bay.

The problem that I have encountered is when I am driving down the street and I let off on the gas pedal the engine dies. I then have to jump start the vehicle to get it running. When I come to a stop I have to feather the gas pedal to keep the car running while also stepping on the brake to stop. I have been told that I am getting a vapor lock in the command center because it's mounted in the engine bay.

My question is I don't know what kind of in tank EFI pump is compatible with my Fitech Throttle Body (part #30003). I was also informed that Fitech throttle body might need to be replaced due to a decline in quality over the past few years. What kind of Throttle body and in tank EFI pump would be best for a 302 engine that puts out approximately 300 hp?

[David Williamson]

The Fitech has a built in pressure regulator so I run a standard in tank pump straight into the the Fitech and a return line to the tank. For 300 hp any Mustang type in tank pump will work fine and you might already have one?
David W

[bobl]

Why does it have to be jump started? Bad alternator or battery? Low voltage will drive an efi system crazy. There have been a lot of problems with those command centers, so that certainly could be an issue. Definitely switch to an in tank pump.

[egchewy79]

I have a #30002 for my 289 and seems to be plenty for the engine. Yes the FiTech has an internal fuel regulator, so you can use any intank pump. I have a 190LPH Walbro in mine. Just do some research on the PWM for the pump. Walbros aren't compatible with this, so you'll need to set your PWM all the way up.
Not sure why you need to "jump start" to restart your car if this is fuel/vapor lock related. check your grounds and make sure the throttle body is grounded. They recommend an extra ground from the TB to the battery.
to your original question about the car dying when you take your foot off the accelerator, you might be able to tune that out by adjusting some of the settings, like the DCFO setting, but I'm not 100% sure. Check your IAC when the car is warmed up to make sure it's in the right range.
Lastly, I found a guy on the FB FiTech forums who did a remote tune for me. I sent him some data logs from longer drives and he was able to adjust my fuel tables for me for optimal performance. He'll also help get you adjusted if you have trouble getting the thing set up in the first place. his name is Ramin Mirshab if you want to search for him on FB. reasonable fees.

[jab351w]

Might be best to verify the source of the problem before you start replacing parts. When the engine dies and during subsequent restart attempts, what do the two gauges on the command center sump read? The high pressure gauge should read between 55-60 PSI and the low pressure gauge should read 4-8 PSI. If either of these are way off from those numbers, it could indicate an issue with the sump or possible vapor lock.



The problem that I have encountered is when I am driving down the street and I let off on the gas pedal the engine dies. I then have to jump start the vehicle to get it running. When I come to a stop I have to feather the gas pedal to keep the car running while also stepping on the brake to stop.

If you have a manual trans and the engine is dying when you push in the clutch as the engine returns to idle, it could be a symptom of mis-configured DFCO (decel fuel cut off--shuts off the injectors while coasting in gear) like Chewy mentioned. You can test whether this is the problem by setting the "DFCO enable temp" to something like 300 degrees, which will essentially disable it.

It would also be helpful to take a data log of the stalling and subsequent restart attempts, as it could help indicate the source of the problem.

[BradCraig]

Holley Sniper has an IAC Ramp down setting that allows idle to return slowly when pushing in clutch or coming to a stop. Maybe FiTech has something similiar?

[jab351w]

Holley Sniper has an IAC Ramp down setting that allows idle to return slowly when pushing in clutch or coming to a stop. Maybe FiTech has something similiar?

The Decel RPM Decay and Decel IAC Decay settings are probably the closest FiTech equivalents. He could try decreasing the decel RPM decay value slightly to see if it helps, but I'd suggest only making small incremental changes as messing with these loop values too much can cause other weird drivability issues. Been there, done that.

But the OP should really first try to determine whether this is a fuel delivery, tuning, or other (i.e. dirty power/low voltage) problem before messing with the tuning parameters as doing that blindly can just make things worse.

[jhamburg54]

thanks everybody i guess i need to get an in tank efi pump