hey all doing a upper and lower intake manifold gasket job on my 98 4.0. Two main questions right now. First, is what did those of u who has done this before do about the fuel rail gasket. In the gasket kits i got, I got a think gasket, and i got a think gasket that has silicone rings on it. the oe gasket is a think gasket with silicone rings. Can I reuse the oe gasket? looks just fine. Second, when i pulled the fuel rail, one of the bottoms of the injector fell off and went into the engine somewhere. I was unable to locate it when i took off the lower intake. Is this going to kill my engine? Im talking about the little cap like thing below the bottom o ring. Also is this going to mess up that injector if i dont have that cap?

 

The injector cap is a problem, it will probably cause that cylinder to misfire. Same thing happened to a buddies 5.4 f150. It fired up fine with the cap inside but it misfired.

 

Can u buy that little cap thing or will I have to buy a new injector?

 

new injector. you really need to get it out. if anything falls into the cylinder while doing the job you are asking for a problem

 

roger that, im hoping an oil change will take care of it. hopefully it comes out with the oil change. will get a new injector

 

The combustion chamber and the crankcase are separated by the piston...you will need to look in the intake port of the head and possibly through the spark plug hole to get it out

 

Yup and if you cant do it that way, pull the whole head.

 

so what u guys are saying is it should be sitting on top of the piston?

 

If it fell through the injector hole, yes.

 

OK I guess ill try

 

yes it will not be able to go anywhere else. if you start or crank the engine with anything in there it can bend or damage a valve, crack the head or the piston. might even break a hole in the piston

 

Got it out. Found in my shop vacation as I was cleaning up around the intake

 

thats a relief

 

not such a relief that the truck is pouring out oil from somewhere now.

 

that sucks

 

tore it back down again and realized i had missed a couple pieces of gasket stuck on the outside part of the head, causing my leak, all is well now.

 

Thanks, guys. I had the exact same thing happen last night. The circular piece that holds the o-ring on came off when I was replacing the o-rings. I put it back on, but while trying to get the fuel rail seated, I noticed that it had come off again, and it has to be in the cylinder. I stopped there, suspecting I needed a new injector. Thanks for confirming.