jcfreeman0

iTrader: (2)

I’m finally ready for to fire up my motor and I cant get it to start. I’ve got a 2001 4.8 truck engine. It has an LS1 intake manifold, 28.8 ls1 injectors, ls1 fuel rail returnless style, MSD fuel pump, Professional Products Fuel Pressure Regulator, Removed EVAP system, Removed EGR, Shorty Headers, 220/222 110 LSA cam, SLP ti springs.

Anyways I’ve tried to get the motor to fire and it fires right up but immediately dies like the computer is shutting it down. Do you think this is a tuning issue at this point? I do believe I have everything hooked up but I could have missed something. Please help!!!

eallanboggs

iTrader: (1)

Could be PCM shutting down the fuel pump. If you have a Passlock or "SECURITY" fault the PCM will shut down the fuel pump. The engine will crank and momentarily run until fuel pressure bleeds down after the PCM shuts the pump "OFF" and the engine dies. Do you see a Passlock or SECURITY message on the IPC? Either way I'd monitor the fuel pump relay to see if it is being deenergized at the time the engine kills. I use a relay socket which I crimped terminals onto the leads for the coil and LOAD circuits and put it in where the fuel pump relay is located. You put the fuel pump relay in this socket and monitor the N.O. lead or the coil circuit using a DVOM or clampon current probe to see if you are losing ground to the pump when the engine dies. You need an assistant to turn the key while you watch the meter to see what is happening. I believe the pump is looking for ground, but you need to check a schematic(Helm, Alldata or Mitchell) to be sure. This problem is more likely fuel than spark especially if it momentarily starts then kills.