runs fine untill i hit the hiway. settings or setup?
I have the 3001 400HP fitech setup. its mounted on an 1986 K20 with a stock 5.7 L31 vortec mated to a TH400
inline fuel pump mounted on the frame rail using the supplied hoses and fittings.
Wiring . + coming from the ECM.- grounded to the frame which is grounded to the battery 4 feet up front.
When i drive around town it preforms fine. When I cruse down the hiway between 2500 and 3000 low load. the AFR spikes and the engine starves for fuel. only way to fix this is to turn off the engine and restart then it runs fine for a little while and does the same. I also noticed the fuel pump isn't making any noise and when the power is cycled the pump comes back and it runs fine again. I haven't hooked up a fuel pressure gauge yet as i am pretty certain its a fuel issue.
If i drive hard and fast it runs fine. this problem just happens during highway cruising and light throttle.
I have turned the DFCO up to 290 degrees to attempt to disable this feature.
target AFRs are setn to 13.7 idle, 14.1 and 14.3
all 3/8 fuel line with 5/16 return lines back to the tank.
The tank is brand new along with the sending/pickup unit. I even ran a hose extension from the return down to the bottom of the tank to avoid cavitation with the return fuel.
Inline fuel pumps can create issues. They are not the best choice.
Running same unit with external pump (44) and no problems at all, thimble vibration mounts to stop most of the noise, mounted level with the bottom of the tank and where the air can flow over it, filter before and after it, OE on many vehicles, had trouble with an import copy initially. If you are getting enough fuel on hard acceleration and high revs it seems that the pump is not at fault. Run wires direct from battery to pump and go for a run to see if the problem still exists. Have a fuel pressure gauge to check pressure also, one can be mounted in the blanked off alternate fuel inlet on the throttle body. I had a lean problem at light cruise and backing off, was a leak at the O2 sensor, fried the sensor and had to replace it, however can be many things. I left the DFCO operating, persevered until I now having it running a dream, only a backyarder but read the tuning instructions and searched the net often for each issue, in my opinion if you disable the DFCO you may a well run a carby.