I've got a 86 302 efi that has spark at the plugs on all 8 cylinders, I've got 50lbs of fuel pressure at the rail. I put a stephoscope on the injectors they all sound the same as far as clicks or pulses. I did a compression check 120 on a cold motor. Any ideas or suggestion would be great. It's cylinders 3,4,7,8 that are down

 

Try to start it. Then pull some sparkplugs and see if they are wet with fuel.

 

Not quite sure I follow. I take it the engine won't start? You mentioned four cylinders "are down". Can you please elaborate on exactly what that is and how you determined that. All I could imagine was you pulled those plug wires one at a time with no change as the engine idled, but I can't see it running well enough to even start with only four good cylinders.

Also, a bit more history, please. Has the engine run well recently? Or was this a fresh rebuild or a junkyard find? Any recent work? The only thing that comes to mind right away is the spark plug wires out of order for the four suspect cylinders. That's where a bit more details and history will help.

 

Big thread here already for any history you might need. Can't fault him for starting a new thread, when they get several pages it's a hassle to try and get through them.

https://www.ford-trucks.com/forums/1...ease-help.html

 

As someone said are the plugs wet from un-burnt fuel?


My guess is they are dry. Even if they sound like they "clicking" does not mean they are not plugged and will not pass fuel.
You can try switching the good cly injectors to the bad and see what happens.


I also seen it posted some where on how to clean them but cant remember where it was. Then again they may be cheap $$ to just get new ones?
Dave ----

 

The dealer has a machine to check the injectors(they used to anyway) I had a car that I took them all out, and went to the dealer and watched him as he put each on on the machine and checked the flow and spray pattern.