ECU ????

so im still having problems with my 93 b2600i. i have narrowed it down that the injectors are not firing. i have checked just about everything and replaced the ecu with another one. the truck did run on this new/used computer for a few days. well today after reading and searching for answers i started thinking about the ecu's again. so i took both both of them apart. one looks burned in a certain area, the other looks like it has coolant spilled in same exact area. is this the problem that everyone see's with these, or is the coolant looking stain normal. any help would be greatly appreciated!

How have you come to the conclusion that the injectors are not firing?

In the meantime, there is a non-start checkout procedure here:

The last picture shows the power supply path to the injectors. It is through the relay. The ECU supplies ground.

ok so there is fuel being delivered to fuel rail on trying to crank, there is fuel coming out the return line when cranking. the fuel pump is working during cranking. try to crank it for awhile and then pull the plugs and out and there as dry as can be. these are brand new plugs. they are getting spark. the relay is good.

i also need to add that i have also put another distributor, temperature sensor, coil, mass air meter,(all the parts came from a running donor truck) trying to remedy the problem. i hate being a parts changer but at this point i do not have all my tools and am doing what i can.

i have a 92 efi computer the number is g618 if you need it

where are you located though

is that ecu for a 2.2 or 2.6 though?

The injectors are grounded at the ECU. If you have aLED test lamp, you can back probe the connector and verify that they are being pulsed.

Although you have fuel, do you have fuel pressure. . . I think you need 45 psi.

I have done some limited diagnoses on FI vehicles, and what I have found is that "usually" the computer has to have a signal from an independant source. . . crank position sensor, cam sensor, mass air flow sensor. . .to "tell" the computer that the engine is rotating, and to turn "on" the injectors. Sometimes a throttle position sensor is used, when closed, to turn "off" the injectors (while decelerating).

These are generic ideas, and maybe looking at the ECU pinout values will provide you with some help.

i appreciate all your help tweaker. it'll be the weekend before i can work on it again so hopefully the weather will cooperate and i can figure this problem out