I have a 1997 F-250 Crew Cab 7.3L with 180K on it. I just purchased it a couple of weeks ago. I took it to a shop and the following work was completed. Replaced the air filter, oil change, radiator flush, replaced the fuel pump, fuel hoses, fuel sensor and breather ring. The truck idles fine with no weird "Clackety Clack" sound until you accelerate. There is no loss of power and the transmission shifts fine. It runs fine with the exception of this sound which is bothersome to say the least. Any possible solutions/suggestions are greatly appreciated before I take it to a different mechanic since the first one couldn't seem to identify the noise. No CEL is present.

Press on...

 

Pull the codes, they won't all set a CEL. Also check the timing and fuel pressure, timing must be checked with the spout plug removed to disable computer advance... base spec is 10deg BTDC, and fuel pressure should be about 40-45psi with vacuum removed from the regulator. If all that checks out the motor is running lean, lots of things could cause that including a leak in the exhaust upstram of the O2 sensor, a failing O2 sensor, dirty injectors, or a leaking smog system.

 

Conanski has given you some great advice, and I'd suggest you follow it. But, one thing I'd like to know is, does this "clackety clack" sound occur all throughout acceleration, or just when you initially press on the pedal? Does it make a difference if the engine is warm or cold? When you hear the sound, do you notice any subtle bumps or vibrations or anything of that nature to accompany it?

I'm curious because although 180k is young for a diesel, sometimes weird sounds just develop with time and mileage. My 5.8, if I accelerate fast enough, a noticeable thunk will hit once, and then I don't hear it again after that. And it only happens when the engine is cold. It's not overly loud, just noticeable. It doesn't seem to be hurting anything and the engine performs just fine, so it's anybody's guess what it could be. But I don't worry about it- if it turns out to be something wearing out, eventually it'll get worse and I'll figure it out. For the time being it's of no concern.

Just a thought. But I would only consider this if you only hear the sound once- if it's constant throughout acceleration, you'll probably need to get something repaired.

 

I'm thinking 7.3L is a misprint?

 

Why would 7.3 be a misprint? It's the only diesel you're going to see in a 97.

I thought there was a TSB on this problem. Something about a cackle. I can't remember now.