Bronco question?

Question

i have a 1986 bronco i hooked a compression tester onto the first spark plug valve on that front of my straight six engine and its only showing 30 lbs of pressure on the tester....what possiblities am i looking at to fix here...could it be a blown valve or something else? when truck is running, and the spark plug is in the cylinder valve, when i take off the distributor wire from that cap theres no loss of power, but when i dissconnect the others, there is loss of power. please help with all your possiblities and how i can fix it. we checked all the other cylinders and they're fine the spark plugs are new...

Answer 1

First, squirt a little engine oil into that cylinder. Not too much a couple of teaspoons is enough. Then check the compression again. If it comes up that indicates worn piston rings. Then run that piston to top dead center on the compression stroke. You then need to blow air into the cylinder and listen to see where the air comes out. If it comes out the throttle body you have an intake valve problem, tailpipe is an exhaust valve problem. from the oil fill cap once again piston rings. Regardless of where the pressure is going you are in for a major repair.

Answer 2

Get a Haynes Repair Manual at the local Auto Zone or auto parts store in your area. It will troubleshoot and show you how to fix your vehicle. Also on the Auto Zone site has a section for vehicle maintenance.
http://www.autozone.com/servlet/UiBroker?UseCase=S001&UserAction=viewSimpleDiagInfo&Parameters=info

So spark plug 1 there is no loss of power but the other 5 there is a loss of power. Did you check to see if the number one plug is getting any fire.Now if it is the first plug you check the compression on and the other 5 are higher then you have a head gasket with a leak. Now if the 1st and 2d or low, and the others are higher then you know that the crack is between the 1st and 2d piston. But get the book and it will let you know what to do. Me just guessing I would think that you might get away with just replacing the head gasket. There are so many other things to ask. Like how old is the engine for one thing.

Answer 3

For one last test, switch that plug wire for another one. COMPLETELY switch it, rotor to plug, with the wire next to it just to be sure it isn't a bad wire. If that's not the problem, you're looking at either a valve job or bad cylinder, meaning worn cylinder or rings or possibly broken ring. None of these are "simple" fixes. The engine will need to be wither partially disassembled (valve job) or completely disassembled (internal cylinder issue). If it's not the wire or head, you might consider finding a salvage motor with good compression/low miles. There's a ton of those motors floating around out there.

Answer 4

definately a blown rod or valve...u need a new car dude !!