Ticking fuel pump
Thread Starter
Burning Brakes
Joined: Mar 2011
Posts: 969
Likes: 1
From: NJ
Ticking fuel pump
So I've been trying to figure out for a while now where the damn ticking is coming from that I kept hearing from the transmission tunnel area. My original thought was the transmission so I kept checking the inspection cover, trimming and bending it to give more room.
Finally just now I opened the passenger side storage compartment and the ticking became louder. Grabbed a mechanic's stethoscope and started searching. I found it coming the strongest from the fuel line that runs right by the right storage box... kept going up the line towards the front of the car and found that the ticking is most likely coming from the fuel pump. The ticking speeds up as the revs go up, which makes sense as the pump has to work faster. At idle it eventually goes away and the stethoscope confirmed this as the ticking was not present anymore at the fuel pump or lines.
So the question is..... is the pump on the verge of going out? This sound has been present for the past 2 years. Should I rush to replace it?
Anybody experienced this before?
Thanks
Finally just now I opened the passenger side storage compartment and the ticking became louder. Grabbed a mechanic's stethoscope and started searching. I found it coming the strongest from the fuel line that runs right by the right storage box... kept going up the line towards the front of the car and found that the ticking is most likely coming from the fuel pump. The ticking speeds up as the revs go up, which makes sense as the pump has to work faster. At idle it eventually goes away and the stethoscope confirmed this as the ticking was not present anymore at the fuel pump or lines.
So the question is..... is the pump on the verge of going out? This sound has been present for the past 2 years. Should I rush to replace it?
Anybody experienced this before?
Thanks
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
I've seen them make so much noise the knock sensor retarded the timing in 81+ model years. And run perfectly. (other than falling flat when the timing went away). How long it'll last is a good question. My answer would be it'll work right up until it quits. But the pump is a pretty easy change too. And $35-40 gets a brand new pump.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Unless you're running some big horsepower, not a thing wrong with the stock pump. My 69 has had a stock pump - from the original 427/435 to the crate L-88 and the current LS-7. Never had any problems running out of fuel. And the original pump was on the car until 2 years ago when I caught it showing a fuel stain from the vent.
As far as changing it, get a new hose from the frame to the pump- it's a molded hose so it needs to come from a vendor- the auto parts store hose will kink. The trick is the pushrod that drives the pump. There are a couple of ways to hold it up while you drop the new pump in. You can put a big wad of grease on the end of the rod, or there's a bolt in the front of the block you can remove and install a slightly longer bolt to hold it temporarily. Do a search for fuel pump and you can see the full threads on the how to part.
As far as changing it, get a new hose from the frame to the pump- it's a molded hose so it needs to come from a vendor- the auto parts store hose will kink. The trick is the pushrod that drives the pump. There are a couple of ways to hold it up while you drop the new pump in. You can put a big wad of grease on the end of the rod, or there's a bolt in the front of the block you can remove and install a slightly longer bolt to hold it temporarily. Do a search for fuel pump and you can see the full threads on the how to part.
Last edited by TimAT; Oct 25, 2013 at 01:01 AM.
Thread Starter
Burning Brakes
Joined: Mar 2011
Posts: 969
Likes: 1
From: NJ
So I am planning on replacing the rubber hoses and filters since this is a perfect opportunity.
Can someone tell me why nobody lists the filter between the pump and carb (the metal canister) for a '70? All I see is 68-69.
Can someone tell me why nobody lists the filter between the pump and carb (the metal canister) for a '70? All I see is 68-69.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
Two possible advantages:
One, the electric pump is remotely mounted, and the fuel line can be routed away from the hot engine. The three port mechanical fuel pumps allow fuel to flow through and bypass the stock pump to cool the fuel a bit, to address the problem of vapor lock.
And, two, you can hide a switch in the wire that powers the electric fuel pump, as an anti-theft device.
One, the electric pump is remotely mounted, and the fuel line can be routed away from the hot engine. The three port mechanical fuel pumps allow fuel to flow through and bypass the stock pump to cool the fuel a bit, to address the problem of vapor lock.
And, two, you can hide a switch in the wire that powers the electric fuel pump, as an anti-theft device.
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Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Two possible advantages:
One, the electric pump is remotely mounted, and the fuel line can be routed away from the hot engine. The three port mechanical fuel pumps allow fuel to flow through and bypass the stock pump to cool the fuel a bit, to address the problem of vapor lock.
And, two, you can hide a switch in the wire that powers the electric fuel pump, as an anti-theft device.
One, the electric pump is remotely mounted, and the fuel line can be routed away from the hot engine. The three port mechanical fuel pumps allow fuel to flow through and bypass the stock pump to cool the fuel a bit, to address the problem of vapor lock.
And, two, you can hide a switch in the wire that powers the electric fuel pump, as an anti-theft device.
Intermediate
Joined: Jul 2013
Posts: 36
Likes: 0
Thread Starter
Burning Brakes
Joined: Mar 2011
Posts: 969
Likes: 1
From: NJ
OK need some help here, this has been driving me crazy for some time now.
When inspecting the ticking with a stethoscope:
--touching the fuel pump - almost nothing
--touching the fuel lines from the pump going towards the back of the car - almost nothing but you do hear the ticking
--fuel line thats routed over the wheel well frame section (not original lines), turning down towards the TArm pocket - no stethoscope needed.....loud and clear!!!
Would it still be the pump/rod? Why would the loudest ticking be at that one section of the fuel line only???
I am holding off with the pump replacement until I am able to somehow explain what is happening here....
When inspecting the ticking with a stethoscope:
--touching the fuel pump - almost nothing
--touching the fuel lines from the pump going towards the back of the car - almost nothing but you do hear the ticking
--fuel line thats routed over the wheel well frame section (not original lines), turning down towards the TArm pocket - no stethoscope needed.....loud and clear!!!
Would it still be the pump/rod? Why would the loudest ticking be at that one section of the fuel line only???
I am holding off with the pump replacement until I am able to somehow explain what is happening here....
Burning Brakes
Joined: Oct 2004
Posts: 801
Likes: 17
From: Middletown Delaware
I had this exact same issue with a 78 only when car was warm and at 2000rpm. Sounded like a problem with the right muffler. I installed a temp muffler on with no change. I finally raised car on lift and ran at 2000 rpm an knocking noise sounded like the fuel lines that run over the frame in the back. With a mechanics scope I located the loudest point which was at fuel lines noted above. I tried to shove rubber in between lines to insulate with no change. I finally put scope on pump and could hear noise but not as loud. I removed pump and the push rod was fine but there was a lot of slop in the fuel pump arm side to side. This was a new pump with maybe 50 miles on it. I replaced pump and guess what no noise. The noise is transmitting down the fuel lines. dave
Thread Starter
Burning Brakes
Joined: Mar 2011
Posts: 969
Likes: 1
From: NJ
I had this exact same issue with a 78 only when car was warm and at 2000rpm. Sounded like a problem with the right muffler. I installed a temp muffler on with no change. I finally raised car on lift and ran at 2000 rpm an knocking noise sounded like the fuel lines that run over the frame in the back. With a mechanics scope I located the loudest point which was at fuel lines noted above. I tried to shove rubber in between lines to insulate with no change. I finally put scope on pump and could hear noise but not as loud. I removed pump and the push rod was fine but there was a lot of slop in the fuel pump arm side to side. This was a new pump with maybe 50 miles on it. I replaced pump and guess what no noise. The noise is transmitting down the fuel lines. dave
Burning Brakes
Joined: Feb 2012
Posts: 925
Likes: 7
I think it's the rubber lines and the joints on either side of the filter. There probably is a factory metal line and filter arrangement from the fuel pump to the carb. That would look better and be safer.
Thread Starter
Burning Brakes
Joined: Mar 2011
Posts: 969
Likes: 1
From: NJ
Correct, there is a metal line and appropriate filter with fittings. But then again these inline filters with inlet/outlet made for rubber and rubber connectors are not unusual either....
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
It's so easy to install an inline filter correctly- cut the line in the appropriate place, drop an inverted flare nut over the tube, flare it and done. And no chance ever of the rubber line growing a pinhole and spraying fuel everywhere. If you want to really get fancy, flare it for AN-6 fittings and go that way.
Melting Slicks
Joined: May 2011
Posts: 2,753
Likes: 119
From: Springfield Missouri
the rubber lines get old, may leak and cause a fire, if the lines were flared, they won't (shouldn't) be a fire hazard. 2 fuel filters are not necessary, they lower the fuel pressure if they start to clog up, no need to have 2, 1 should be enough, that's what the came out of the factory with! The factory did not put rubber because of the fire hazard possibility. Ever seen a car go up in flames because of a gas leak???