I started a similar thread on this a few days ago but now that I have it pinpointed I figured I'd start another. Originally I thought I had a bad injector that was making a rapid metallic ticking sound but then thought it was the air pump plumbing. 1996 351W

I got a hold of a long thin screwdriver and was able to pinpoint the sound. It is coming from the fuel rail. It still sounds like it is coming from the right (facing the engine) towards the front and I can feel a vibration (same timing as the tick) across the entire fuel rail. It was really vibrating the pressure regulator and the lines going down behind the engine.

I unplugged each injector on the right side one at a time and it still made the clicking sound/vibration. I cannot easily unplug the injectors on the left side so I only touched each injector to see if one was vibrating more than the others and they weren't from what I could tell.

Question - what would make a fuel rail vibrate and tick like that? I would think if it were a small leak somewhere gas would be spraying everywhere. Whaddya think?

Thanks

 

Its not the fuel injectors pulsing?

 

I don't think so. It is a loud metallic click that sounds like a stopwatch. The rail vibrates pretty good and but injectors only vibrate a little.

 

take the injectors out grab a bfh and bash the **** out of them until u feel good about it...

then go buy new ones and put them in make sure everything is secure...

if its still making the sound pop ur valve covers off and find ur loose rocker and beat the hell out of it to and put some new lifters and 1.7 rockers on it tighten them down and put it back together

try it then... should be silent...

mine was ticking only a little before and u would thing it was the injectors firing then it got to be a quart and half low that made it sound like a freakin mack truck

 

That's the one thing I forgot to mention. They are new injectors, or refurbs I should say.

 

they sell faulty parts...

i have had more than my fare share... and it wasnt every now and then it was one right after the other

 

Ok, here is an update on my troubleshooting efforts.

Every fuel injector was unplugged one at a time the rail still ticked and vibrated. I held a long screwdriver up to both sides of the rail and each seems to tick at about the same strength. Fuel pressure is at ~41 with the vacuum off and ~31 with it on.

I did notice on the right side of the engine (facing it) right after you shut it off it makes a faint percolating leak sounding noise by the fuel rail. Kind of like barely cracking a pop bottle. I do not see or smell gas (well, I smell a little gas vapor but nothing out of the ordinary IMO).

 

pressure leaking out of the valves in one of the cylinders ?

kinda what it sounds like the sound ur describing by the cracking a bottle open

 

The fuel injectors will make some noise, some more than others. Has the truck always made this ticking noise, or is it just a recent development?

 

I know injectors will always make a noise but it seems to be louder post-replacement than usual. Now that I think about it I feel like my Mustang's replacement injectors were louder than normal too, unless I screwed those up as well.

Last night I took the right-side fuel rail off, replaced the new o-rings with the old ones and it seemed to quiet it down a bit. Unless it is just in my head. The old o-rings are smaller but wider. It now sounds more like a symphony of finely tuned pieces of machinery than one or two loudly clicking offenders but it is still loud. Maybe everything just needed to be reseated but I'm still not convinced it is correct. Replacing the o-rings shouldn't matter.

I dunno... I wish I could get a sound sample so you could tell if it is louder than it should be. With the hood open you can clearly hear it over the running engine.

Should the fuel rail 'pulse' when active (when one touches it) or should it be running smooth?

 

There should be some vibration in the fuel rail due to the injector pulse, but it shouldn't be loud enough to hear over the engine.

Since you pulled the right side off, I'd advise checking the torque the left side fuel rail mounting bolts. If they're loose it could be vibrating more than normal.