MSefi.com read only forum (Jan.15,2018)

So I have a problem with not getting any fuel from the injectors.

I think it is a fault in my U4 circuit for INJ1, this is because when I ground pin 21 of U1 (INJ1) I do not see the led for INJ1 on the stim come on, when I ground pin 22 of U1 (INJ2) I see the INJ 2 light come on at the stim.

When I ground pin 2 of the FET driver (U4) I see pin7 only go to (390mV) and no led.
When I ground pin 4 of the FET driver (U4) I see pin 5 go high (8v) and get the stim INJ 2 led on

I have 5volts to pin 2 and 4 of U4

I have 3.5v to signal in on both Q1 and Q5.

I have installed a socket and replaced U4 with same part as supplied with no change.

Not sure what to test next, I have read quite a bit on previous posts, I did clean board with isopropyl alcohol and tooth brush and took care with anti-static control during assembly. Any pointers from the electronics gurus?

Nevermind I had the diode installed back to front in the INJ1 circuit

Is it possible that this reversed diode (D17) could have damaged something?
I still have no fuel from the injectors?
After turning around the diode (D17) I was able to achieve a light from both LED1 and LED2 on the stim when pins 21 and 22 were bridged to the grounding strip.

Okay I have found the issue.

The coil for activating the injector relay is being grounded at both sides.

The positive to this coil is spliced into the fuel pump positive. For some reason I have 1 ohm across the fuel pump terminals.

The fuel pump is wired up as per manual ( +ve to relay and -ve to chassis ) and it puts out good pressure ~35 psi

Thanks for your time

I cant report the definite fix of this problem but I can narrow it down to one of three things.

Firstly because my car came out of the factory with a carburetor I had to install a fuse box and extra wiring, I was trying to follow the OEM wiring diagram for switching the relays without much luck. In the end I went with gut and used the single 12v switched wire in the bay to run all the control circuits for the relays and then wired the switches to battery with fuses.

Secondly I found the condition of grounding points in the engine bay awful so I removed them all gave them a good sand back and reinstalled with vasoline.

Lastly I did replace my fuel pump however the old one seemed to work just fine.