When my ECM Went out on me the Temp Gauge Peged and it kept going in and out of limp mode

 

does it with our with out box on.

 

Turned off or Un Hooked ?

 

Unhooked completely!

 

Check your under the hood Fuse box also

Its got to be something simple

 

Trust me DM i have been all over it, its been down for a couple months, i am at my wits end with it now!

 

You can have normal FP but no fuel being delivered if the internal bypass is worn out on your LP. I fought this one myself. The rotors were turnin but nothin was being pushed.

 

I have a holly blue with no factory lift pump, this is what i thought, took off filter lid pump fills with no problem, so pump is pumping great.

 

Any chance you may have tightened the injector tubes down to tight when you re-installed them. These tubes will crush pretty easy and make for a bad seal. I know on my 99 they were intended to be disposable and replaced anytime you pulled a supply tube.

 

A Stretch But i bet your willing to try anything , So Here it goes ..

Run a Set of Jumper cables from the Negative Battery Terminal to your Engine Lift Hook to ensure the Engine is Grounded Really Good , Then Stick a 12V supply on the Positive of the Fuel Pump then try to start it

Maybe when your Cranking and the AMP draw hits the Batteries it slows the pump down Or you have a bad ground ..

Time to try anything