ALDL JUMPER WIRE

If the engine is cutting off, then we need to find out what we don't have. Fuel or spark?

Code 12 means the system is normal and there are no trouble codes.

Here is a guide that will talk about this:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

I would suggest using starter fluid in the intake and see if the engine fires.

If it does, then we have a fuel issue.

We can also check the fuel pressure using this guide:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please run through this info and we can go from there.

So, if this is a fuel related issue then we need to jump the relay and see if the pump comes on. Also, we can go to the pump and check for power when the key is in the on position.

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-wiring

If you have power but the pump is not coming on or you don't have pressure, then you need to replace the pump.

If the pump is not coming on, then we need to back track through the system to find out where we are losing the power.

I am attaching the wiring diagram below which will help with figuring this out.

Let me know what questions you have with this.

Thanks