79 tapping noise... fuel pump...
Thread Starter
Intermediate
Joined: Aug 2001
Posts: 44
Likes: 0
From: no where IL
79 tapping noise... fuel pump...
Why the heck is this tapping noise coming from my fuel pump which pings back all the way thru the fuel lines? I can hear it the loudest near the right (passenger side) wheel where the fuel lines run next to the frame. I have a replacement pump, which i am positive i installed correctly. I measured the push rod, and it is almost exactly 5.75 inches. Can any one think of a reason why this tapping noise continues after replacing the pump? I broght it to a local mechanic who said the noise is definitely coming from the fuel pump...
Please help!
Please help!
Melting Slicks
Joined: Mar 2001
Posts: 3,365
Likes: 5
From: Lake Villa IL
Cruise-In IV Veteran
Cruise-In V Veteran
St. Jude Contributor
Re: 79 tapping noise... fuel pump... (dkgrn79)
Are you sure the pushrod is seated properly? Did you place grease or assembly lube on the end to hold it in place, as you installed the pump?
That's all I got... :(
That's all I got... :(
Drifting
Joined: Feb 2001
Posts: 1,603
Likes: 0
From: San Francisco, CA
Re: 79 tapping noise... fuel pump... (Gary79)
I read of a similar problem in Corvette Fever or Vette in the letters to the editor or whatever they call it section but can't find the issue. (was the last couple of years issues I think). Anyway, the advice of the author was that this is possible and is a sign of a bad pump.
Thread Starter
Intermediate
Joined: Aug 2001
Posts: 44
Likes: 0
From: no where IL
Re: 79 tapping noise... fuel pump... (dkgrn79)
Yah, I am pretty sure that the rod was seated properly. I used a big dab of grease to keep it from falling. I'll check the manifold bolts tonight. If that doesn't do it, i'll try (another) new pump.
Thanks for your suggestions. I'll post my results when i figure this out!
Thanks for your suggestions. I'll post my results when i figure this out!
Thread Starter
Intermediate
Joined: Aug 2001
Posts: 44
Likes: 0
From: no where IL
Re: 79 tapping noise... fuel pump... (dkgrn79)
Okay, is the rocker arm on the pump supposed to move around? It seems really loose. If i push real hard, i can compress the arm and make the pump go, but i can grab the rocker arm with two fingers and wiggle it all around, up, down and back and forth... is this normal for a new/rebuilt pump?
Anyone know?
I hate tapping noises..
Anyone know?
I hate tapping noises..
Racer
Joined: Jan 2000
Posts: 491
Likes: 0
From: florida
Re: 79 tapping noise... fuel pump... (dkgrn79)
While you have it out, I think you should put in a new fuel pump rod. It's only a couple of buck at any auto parts store. That's what I had to do to get mine to stop tapping after I change the fuel pump. lou
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: 79 tapping noise... fuel pump... (dkgrn79)
If you feel like getting real crazy, put the base plate on with some tape over the pump hole and start the car without the pump installed. Car won't run very long but will tell if the noise goes away. Worse case is the pump lobe on the cam is gone, hope not. :(
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Burning Brakes
Joined: Jul 2000
Posts: 1,045
Likes: 3
Re: 79 tapping noise... fuel pump... (Fevre)
Heres a long shot. In 1979 Cheverlot saved a few cents in the hardening prosses on small block cams. The result was cam lobes rounded off.
I had to chenge out my cam ofter four years and twenty thousand miles. GM agreed the was way to low milage for a cam to round off three cam lobes.
GM paid for a new cam, lifters,gaskets and a few other small things admiting the had a batch of bad cams.
Maybe your fuel pump cam is worn and has too much slack causing the rattling.
My car has a serail number of 29xxx so it's about mid production. I hear the problem was 78 to mid 79.
Like I said a long shot but worth looking into...
I had to chenge out my cam ofter four years and twenty thousand miles. GM agreed the was way to low milage for a cam to round off three cam lobes.
GM paid for a new cam, lifters,gaskets and a few other small things admiting the had a batch of bad cams.
Maybe your fuel pump cam is worn and has too much slack causing the rattling.
My car has a serail number of 29xxx so it's about mid production. I hear the problem was 78 to mid 79.
Like I said a long shot but worth looking into...
Race Director
Joined: Aug 2000
Posts: 18,478
Likes: 3
From: Quincy IL
Re: 79 tapping noise... fuel pump... (toyvet1)
i had a bad cam in a 305 V-8 in my 78 chevy van, 23,000 miles, went to the dealer, nothing wrong, kept going thru fuel pumps, til i put an electric pump on it. Didn't find out about the "soft" cam problem until fall of 1985 when i was at a different chevy dealer buying a Celebrity, by that time my van was out of warranty and i had lost all paper work on oil changes and maintenance, so i was out. GM also changed alloy composition on their front springs on some 1979 cars and most of their 1980 GM car line. i had a Pontiac Sunbird with soft springs and my Mom had a 1980 Olsmobile Delta 88.
Thread Starter
Intermediate
Joined: Aug 2001
Posts: 44
Likes: 0
From: no where IL
Re: 79 tapping noise... fuel pump... (dkgrn79)
Well... maybe thats it then. Time for an electric pump. I did tighten my exhaust manifold bolts, thanks for that advice gary79, however; the tapping noise persists....
DOH!
DOH!
Thread Starter
Intermediate
Joined: Aug 2001
Posts: 44
Likes: 0
From: no where IL
Re: 79 tapping noise... fuel pump... (dkgrn79)
Replaced the push rod this weekend. That Didn't help at all. I'm thinking about getting a longer rubber hose that runs from the pump to the metal fuel line to see if i can deaden the noise a bit.... any one have any other ideas?
Racer
Joined: Jan 2000
Posts: 491
Likes: 0
From: florida
Re: 79 tapping noise... fuel pump... (dkgrn79)
Only thing else I can think of is make sure your new pump is the correct part, if it is, I would return it and try another one. After that, the only thing left is the cam but I thinking if it was the cam it would have done it with the old fuel pump. So if it made that noise with the old pump, you might be looking at a bad lobe on the cam. lou
