my friend has a 94 f150 5.0l bored .30 over and he wants to do a compression check on it to make sure it is still doing good, cause he had problems with the fuel pumps not putting out the right pressure.


to do a compression check on it is all he has to do is disconnect the coil wire and just pull out the plugs and just crank the engine?

and what are the cylinders compression supose to be at, we cant find anything in the haynes manual?

 

Are we talking fuel pressure or engine compression. Am confused. If its compression. Gauges are all different, procedures are never followed per manufactures recomendations. Its a long story, to get to the bottom line. Pull the plugs and take your readings. Look for all readings to be with-in 10% of each other. That tells you of a potential problem. My gauge and procedure shows 100-110 as the normal, specs say 150-160. Bull punky, have never seen any readings that high. But thats me and my gauge testing alot of engines.

 

Check Chapter 2 Part D (general engine overhaul procedures) of your Haynes. Lowest cylinder must be at least 75% of highest cylinder.

 

engine compression im talking about. he said someone told him he has to disconnect something so you dont fry the computer but i told him that all he has to do is just disconnect the coil and pull the plugs to test it.

 

You could also use a remote starter button tied into the starter solenoid on the passenger inner fender. This allows you to crank the engine over without injecting fuel or even firing the coil without any disconnects.