What would make the injectors in a 1987 F 150 EFI 302 stay open?Anytime the key is on and the pump is running the cylinders are filling up with fuel regardless if you are cranking the motor or not.


OK , so we unplugged all the inj's. Now when the key comes on the fuelpressure gauge still only shows about 45psi and it drops off instantly when the key is turned off. We havent turned the motor to see if the cylinders are still filling up , but, there are no leaks in the fuel system. IOW's there isnt a visible puddle of fuel or a leak anywhere.

What I am having a trouble grasping is the truck has 8 inj's. What are the chances of all 8 being clogged at once? The problem just came on all of the sudden. It wasnt like it started running bad and then got worse. It just all happened at once.

 

Sounds like the injector relay might be stuck closed.

 

That or the ecm is shorted out.
By the way welcome to the forum

 

Let me run this by you guys. We pulled the computer off of the firewall. We opened it up , but , didnt see anything that looked burnt. So we were closing it back up and just happened to notice that not only was it a salvage unit, but , also it says right on the case that it is for 3.0 taurus/sable only. So my question is could this be the problem or these ecm's somewhat universal?

 

the 3.0 taurus engine is totally different then any engine the f150s run its the wrong one you need to get the proper ECU in there.

 

Take your VIN # call or go to a ford service dept. they can get you the right # so you can match it when you go looking for the one you need.

 

I would also check the fuel pressure regulator if pressure is dropping as soon as you turn the key off. If its stuck open it could be letting fuel fill up through the injectors that are open from the cycle.