How come the fuse for my fuel injection blows everytime I turn the key on and occasionally the ecm fuse above it blows the truck has run great up until this morning any idea's

FSCM Fuse
25A
Fuel Pump Flow Control Module , under hood fuse/relay box.
do you know what a fuel pump control module is ?
The in-tank fuel pump is controlled with a fuel pump control module (FPCM). The engine control module (ECM) enables the FPCM and sends the desired fuel line pressure to the FPCM via GMLAN. The FPCM sends a pulse width modulated (PWM) voltage to the in-tank fuel pump allowing the fuel line pressure to be varied as commanded by the ECM. The high pressure fuel pump, fuel rail pressure, fuel injection timing, and injection duration are controlled by the ECM.

I would bet that the fuse isn't the problem ! Don't get me wrong , the fuse could be blown but fuse's don't blow for no reason . The fuel pump control module .

Video on youtube fuel pump control module diagnostic's .

ecm1 is injectors not fuel pump ecm-b is fuel pump its more likely to be a faulty relay for the injectors, it would be a similiar design to this
this is for the fuel system, relay for the injector is nearly the same.

Sounds to me more of a wiring problem with a wire too thin or the wire insulation going to ground causing fuse to blow.

fuel pump is bad. pump motor is shorted.

Well you have a short and still have to narrow it down.
How difficult that is depends on what attaches to that fuse.
If it is just the ecm, then disconnect that and see if the fuse still blows?
(if you want to stop wasting fuses, you can just use a test light in its place.
If you have a short, the 12 volt light will be bright. If things are normal, then the 12 volt light will be dim because in series it will only be getting 6 volts.)
If removing the ecm stops the fuses from blowing, then take it in and have it tested.

if there is no power to the fuel pump check relays and fuses....UNDERHOOD FUSE & RELAY PANEL IDENTIFICATION Fig. 2: Underhood Fuse & Relay Panel Identification Courtesy of ISUZU MOTOR CO. Fusible Link Identification ? A - 80 Amp (1991-92 3.1L) ? A - 60 Amp Main-1 ? B - 30 Amp Main-2 ? C - 30 Amp (1993-94) ECM (3.2L) ? D - 30 Amp Condenser Fan (A/T Models) Relay Identification ? 1 - Headlight Relay ? 2 - A/C - Heater Relay ? 3 - Starter Relay ? 4 - A/C Compressor Relay ? 5 - Charge Relay ? 6 - Fuel Pump Relay ? 7 - ECM Relay ? 8 - Wiper Relay Fuse & Circuit Breaker Identification ? 1 - 15 Amp (1991) ECM, Fuel Injection System ? 1 - 15 Amp (1992-94 2.6L) ECM, Fuel Injection System ? 1 - 10 Amp (1992-94 3.1 & 3.2L) Heated Oxygen Sensor, Fuel Injection System ? 2 - 20 Amp (1991-92) Fuel Pump ? 2 - 20 Amp (1993-94 2.6L) Fuel Pump ? 2 - 15 Amp (1993-94 3.2L) Fuel Pump ? 3 - 10 Amp (1991) ? 3 - 15 Amp (1992-94) Turn Signal Lights, Hazard Warning Flasher Lights ? 4 - 10 Amp Horn, Door Locks ? 5 - Not Used (1991 3.1L) ? 5 - 10 Amp Charging System, Charge Warning Light WARNING: Always disconnect battery ground cable before servicing "high- current fuses. It is recommended that "high-current" fuses be replaced by a qualified technician. Page 1 of 2 FUSES & CIRCUIT BREAKERS -1994 Isuzu Rodeo LS? 6 - Not Used (1991) (1992-93 2.6L) ? 6 - 10 Amp (1992-94 3.1L & 3.2L) A/T Interlock System ? 6 - 10 Amp (1994 2.6L) Heated Oxygen Sensor, Fuel Injection System ? 7 - 20 Amp Heater/Air Conditioning Blower Controls ? 8 - 10 Amp Air Conditioner Compressor Controls ? 9 - 10 Amp Right Headlight ? 10 - 10 Amp Left Headlight © 2008 Mitchell Repair Information Co., LLC.

Underhood fuse block swap out relay #7 thats the ECM relay.
Ground Circuits Using a DVOM, touch negative voltmeter lead to a good ground. Touch positive voltmeter lead to each ground terminal. With vehicle running, voltmeter should indicate less than one volt. If reading is greater than one volt, check for open, corrosion and loose connection on ground lead. See ECM GROUND LOCATION table for ECM ground location.
Page 1 of 1 SYSTEM/COMPONENT TESTS - 2.6L EFI -1994 Isuzu Rodeo

Check the fuses, I had one a while ago that kept blowing one of the ECM fuses. There are 2 ECM fuses one also sends power to the fuel pump too. Do you hear the fuel pump run when you turn the ignition switch to on? Just turn the key to the "on" position, not all the way to start, you should be able to hear the fuel pump run for about 3-5 seconds. I think it takes a 15 amp, I showed the owner which fuse it was and it would blow occasionally. One day it blew one right after another so he put a 30 amp in, he was out of 15's. I told him that was not a good idea. Anyway, that fixed it he drove it home and put a 15 amp fuse back in it, it's been good ever since.

Look for a bad fuse or relay. If both check out, most likely an ECM problem

it will not blow when ECM is disconnected, cause there is no power to the injectors when you disconnect the ECM. When you turn ignition on check for fuel pressure at fuel rail. Release pressure at nipple on fuel rail. If no pressure exists puel pump is shot. If there is pressure your fuel filter might be plugged.

That fuse provides power for the fuel pump. Either your fuel pump is blowing the fuse or there is a shorted wire.