13mm pump clatter noise?

RonA

RonA

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Joined
Feb 26, 2008
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I've had my 13mm pump on a bit over a month but haven't had a chance to put my foot down since my cam/spring/gear issue. When I went towards full throttle I started hearing a clatter noise and backed off. I later found that my valves were hitting the piston and assumed that was the clatter i heard. After a new cam/gear/springs/valve job and a couple of retorques, I pushed the pedal down today. The first time I forgot to turn my FASS on(so I was running on just the piston pump. approx. 20-25 psi min). My afc is very tight and doesn't allow full fuel till about 55psi of boost. Right around that point is where I heard the clatter again. I rolled out of it and turned the FASS on(45psi). I tried it again and went to nearly full throttle for a few seconds. No clatter. I am running with the plate back towards the back, probably around 575-600cc. I have .084 lines, .093 tubes, but am running 181 DV's(yes, I know). Do these pumps clatter when the pressure get's low? I have to add that the pull at full throttle in 3rd gear locked is bloody intense. Sure would appreciate some feedback.
 
To me it sounds like you are running it out of fuel . Stock fuel system spec is 38 to 42 psi with a minimum of around 25psi. 13mm require alot to keep happy IMO.
 
I heard the same thing when I had the (incorrect) low pressure spring in the FASS.
 
Smokem said:
I describe low pressure under heavy throttle as chatter, so if they rhyme they should be the same symptom.
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Thank you for the info. My rear end is puckered up pretty tight after hearing the noise. Last time I heard it, it cost me a bundle and could have been alot worse.
I need to get some sort of mechanical pump installed that can handle it so I can ditch the FASS. It makes enough noise to wake the dead. Too bad the mitusa won't fit on a first gen(cross member clearance).

Ron
 
Kinda random, but do you have any pictures of your truck on here? Gotta love a fast 1st gen!
 
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