Cold starting, possible Fuel Injection Trouble??

Question

I have a 93 astro-van 4.3 liter w / port Fi, it wont start when its cold. it runs fine once I use starting fluid. but if it hasnt run for a couple of hours it just wont start without starting fluid.if it had a Carb, I would just rebuild it but I dont know much about Fi. I checked the engine codes and all I got was code 12 (about 15 times over and over) someone please help!
Thank you

Answer 1

Code 12 means there is no ignition pattern detected. Don't jump to conclusions, because that is a normal condition when the engine is in the "Key On Engine Off" state.

It sounds like what you have is a fuel pump relay problem.
The easy way to check this is to wait until the car is cold, and you are sure the problem will happen. Then simply turn the key forward so the lights on the dash come on but the engine doesn't start. When you do this you sould be able to hear the pump inside the tank run for approximately 3 seconds. If you aren't sure if it came on, turn the key off for ten seconds, and try again.

Here is a little insight into how this works: You turn the key on, the computer sends a signal to the fuel pump relay to prime the pump. After 3 seconds the computer stops sending the signal. But how does the engine continue running you ask? Easy! Heres the part most folks don't know: Your oil pressure switch has an output that sends power (directly) to the fuel pump any time there is oil pressure. This is a saftey feature designed to prevent the fuel pump from continuing to run in the case of a catastrophic accident. How does this relate to my problem you may ask? Here's how: If your fuel pump refused to run on the previous test, crank your engine until it begins to build oil pressure, the if the fuel pump starts to run then, you just have a bad fuel pump relay.