Runs great then dies
600Hp unit on a Chevy 383 in 66 corvette using a Tanks Inc tank with GPA-4 pump on keyed relay, LS style regulator, MSD 8572 phased/locked out distributor with MSD 6AL cap discharge ignition. Controls electric fan, still has trouble code 74, don't know why.
Vehicle dies after 20 minutes of driving, most times able to restart and limp back to shop. No power, dies every time I stop at a light, feels like no fuel pressure. Drives fine the next day then repeat problem, takes between 10 minutes and 1 hour for problem to arise. Car is a rocket until it dies.
Troubleshooting completed:
Disabled electric fan
Replaced regulator in throttle body,
Replaced distributor,
Installed ground wires from battery to engine to starter to frame to throttle body
Insulated distributor signal wires
Air bubbles in fuel return?
Removed fuel pump wire from fitech and installed keyed relay,
Switched to GM corvette style fuel regulator
Switched from GPA-2 pump to GPA-4 pump, replaced entire fuel pickup unit in tank.
Pressure tested regulator, supply and return lines to 120 psi fuel pressure
Bought replacement Fitch unit, returned old one,
Been on the phone with support countless times. There must be a software update or something.
Next step will be to send Fitech unit back and buy Holley unit unless you have any bight ideas. Still feels like it loses fuel pressure, but that is nearly impossible at this point. There is still a very small amount of air bubbles in the return line that I can see when i look down into the tank, before I stitched regulators and pump it was significantly more.
I have installed more than 15 of these in the past five years and never had a problem. If you can't help me I won't be able to buy them from Fitech anymore. See attached log or follow dropbox link:
https://www.dropbox.com/s/vzoajj3isv6ijdm/DashBoard3.csv?dl=0
Thank you,
Noah
I would suggest that a fuel pressure gauge that is visible from the car will tell you what the pressure is when the failure occurs. Do not install a fuel pressure gauge in the car unless it is an electric one. Sounds like you already know that. If you have already done this what is the pressure situation when it fails and during the limp back to home?
Hi Bill,
I had an inline analog gauge on it for a while, difficult to read while problem is occurring because it rarely happens while not driving the car on the road. I haven't seen any electric gauges, is there a specific product you are referring to? It looks like dakota digital makes a product that is designed for a more permanent install, but i have not seen any troubleshooting tools available to remotely view the fuel pressure.
I find it extremely unlikely the fuel pressure is the problem considering we have replaced the entire fuel system and used 4 different regulators and tested all the lines at more than 100 psi, but buying something to be able to read fuel pressure while driving the car around for troubleshooting is probably a very good investment.
I just teed off a hose for an analog fuel pressure gauge so i can see it from the drivers seat, it has 56 psi the whole time it is falling on it's face.
If a carby, I would say coil related.
just happened; gauge reading going down to about 30 with fuel pump on, so I turn it off, wait until gauge reads 0 psi, then remove gauge, fuel sprays out(lots of vapor bubbles), install different gauge, reads 58psi with key on. I've never had a unit vapor lock, but it sure does seem like it is vapor locking to me.
Anyone ever had vapor lock on one of these?
If a carby, I would say coil related. To expand on that, in my '69 Firebird the coil wire resistance increased as it got hot, the voltage dropped to about 8 volts, was designed for easier starting with lower voltage coil.
Certainly should not have air bubbles in-the-line. I would recheck all your AN connections. Also, potential bad fuel pump (overheating)? I had this with an "inline pump". Would overheat and cause lean condition & shut off. I ditched my Mallory fuel pump and went with an Aeromotive.
I ended up switching it back to the fitech regulator with key controlled fuel pump, insulating the fuel lines, fixing the fitech MAP sensor issue, and wrapping the signal wires from the distributor for the TB in aluminum foil. The aluminum foil made an immediate difference and I have now put about 100 miles on it without a problem. I'm probably going to do this on every car now, just as a precaution, this car has a lot of EMF, I think it has something to do with the fiberglass body as well, because I've never had a problem with an MSD signal like this.
Car just came back, won;t even prime, vacuum noise from throttle body when pomp is one. Has fuel pressure. Reads 165 RMP while cranking and has injector faults on all injector.
I found the fix though.
BOUGHT A HOLLEY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!