Fueling frustrations, pressure drops
05-07-2017, 05:12 PM
#1
Teching In
Thread Starter
Fueling frustrations, pressure drops Looking for some insight into some fuel issues. I have a ~500hp Gen I 408ci SBC, running a FiTech EFI 8 EFI kit. Now, this Fitech system was installed using the Fitech Fuel Center and initially worked great for many months, slowly developed the chronic issues these systems are known for, boiling over, liquid fuel from the vent hose, etc. Eventually this turned into a loss of fuel pressure after the truck was running for a while, causing the motor to cut out.
Following this, I finally decided to delete the FCC completely. I've since bought a brand new Aeromotive A1000 pump, Holley 12-879, Aeromotive 100 micron pre-filter, and all new lines. So the system goes as such: prefilter is gravity fed via 1/2" hose from a 12 gallon poly cell (vented w/ -6 hose), this is attached directly to the A1000, immediately attached to the holley regulator (no vacuum reference is hooked up), which returns via -8 hose. Feed line from regulator is -6 to the TB, where the internal regulator is blocked. Feed goes through the Fitech supplied 40 micron filter, (which i've tried running without the element, suspecting it might be the culprit)
Now to the problem, I continue to have pressure drops, pretty severe ones. The truck sits at 58 psi at idle, which is the required pressure for the FiTech unit, it maintains the pressure fairly well (some small intermittent drops) while cruising. However, the instant i burp the throttle, the pressure will plummet to about 45 psi, and with sustained wot, the pressure maintains around 30-40psi, which intern causes the engine to go leaner and leaner until i let out, reaching as much as 19.5 afr. Now I am highly suspicious that it is a pump problem, it is wired through a relay direct to the battery with 8 gauge wire. Could this be a matter of the regulator being so far back in the system? Could lack of a check valve have anything to do with it? Thanks in advance
Following this, I finally decided to delete the FCC completely. I've since bought a brand new Aeromotive A1000 pump, Holley 12-879, Aeromotive 100 micron pre-filter, and all new lines. So the system goes as such: prefilter is gravity fed via 1/2" hose from a 12 gallon poly cell (vented w/ -6 hose), this is attached directly to the A1000, immediately attached to the holley regulator (no vacuum reference is hooked up), which returns via -8 hose. Feed line from regulator is -6 to the TB, where the internal regulator is blocked. Feed goes through the Fitech supplied 40 micron filter, (which i've tried running without the element, suspecting it might be the culprit)
Now to the problem, I continue to have pressure drops, pretty severe ones. The truck sits at 58 psi at idle, which is the required pressure for the FiTech unit, it maintains the pressure fairly well (some small intermittent drops) while cruising. However, the instant i burp the throttle, the pressure will plummet to about 45 psi, and with sustained wot, the pressure maintains around 30-40psi, which intern causes the engine to go leaner and leaner until i let out, reaching as much as 19.5 afr. Now I am highly suspicious that it is a pump problem, it is wired through a relay direct to the battery with 8 gauge wire. Could this be a matter of the regulator being so far back in the system? Could lack of a check valve have anything to do with it? Thanks in advance
Last edited by Jason Hunt; 05-07-2017 at 05:33 PM. Reason: Adding photo
05-10-2017, 04:41 AM
#2
9 Second Club
Whilst a -6 line from pump to engine should be more than adequate for your power needs...being a dead end setup it could be worth going large
The closer the regulator is to the engine, is always better.
The closer the regulator is to the engine, is always better.