New installed and dies
Just installed the 70051 on my 5.3, having a issue at start up where it runs for about a minute then dies and the fuel pump turns off and on rapidly. Even when having the key in the on position for a few minutes the fuel dump does the same thing. Not sure what it be.
What kind of fuel pump do you have and where is it located?
What fuel pressure do you have at the fuel rails while it is running?
Where are you getting the ground for the fuel pump at?
Good grounds and power are very important. Where are you getting your main power and ground from?
I suggest you install a fuel pressure gauge in the somewhere in the fuel rail at least until you have any bugs and tuning issues figured out and it's running well.
I have a hyperfuel in tank 40015, 255 lph.
Ihaven’t checked the fuel pressure yet.
Fuel pump grounded to the truck frame
All wires hooked up according to the manual. Power from starter and grounds on back of heads.
Truck was running before no problem, I replaced my reworked harness for this one.
Quote from kc10 on July 25, 2021, 10:22 pmTruck was running before no problem, I replaced my reworked harness for this one.
OK, so this is a problem that developed after the system was running good.
Have you confirmed the fuel filter is clear?
If this was an old tank, there may be trash clogging the pump pickup sock/screen.
It could also be a pump problem. If you didn't upgrade the fuel pump feed wire to say, 10 gauge for the long run to the tank, it might have low voltage which can damage the pump.
The gauge will tell.
Fuel system and tank are new. I don’t think it’s 10 gauge but if it could be a problem I will change it.
Just talked to fitech he wanted me to check any voltage drop at the key power. He did say the fuel pump shouldn’t be the problem.
Fuel pressure is good.
Talked to them again and he recommended to connect key power and grounds to battery. Still doing the same thing. I’m thinking it could be a bad ecu. Saw another post that was exactly the same problem as mine and a new ecu fixed his. Will call them back again to see what they say.