Gremlin in the fuel tank?

Whenever I start my car, it sounds like someone with a small mallet is banging against the side of the fuel tank every second.

Any thoughts?

For how long?

As soon as you stick the ign key in?

Just whilst it's spinning over on the starter?

All the time it's running?

Early-1800 said

For how long?

As soon as you stick the ign key in?

Just whilst it's spinning over on the starter?

All the time it's running?

My fuel pump runs permanently with the ignition  on

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The only time I have experienced  strange noises coming from the fuel tank was with a Caterham. The baffles in the tank had become loose and were floating around. The car also has tendency  to stall when fuel was low going round sharp corners.

Sounds as if your fuel pump relay is toasted.

www,cabby-info.com has info on the relays and which ones to avoid as the circuitry is different.  Yes there are a few bad ones out there.

Just had this happen to a guy in Chicago on his 92…

I can't remember if it starts with ignition on, or only after the engine has started - it definitely continues for about a minute after the engine is started.
I'll record the sound next time I'm in it.

As far as the fuel pump goes, the is an initial buzz when you turn the engine on, then a different constant sound with the engine running. I think this is normal.

Something moving in the tank sounds quite possible. It's as though something that turns is tapping the side.

My 92 has a K-jet instead of the Digi now. Is it possible that it's the same relay issue?

the_whip said

I can't remember if it starts with ignition on, or only after the engine has started - it definitely continues for about a minute after the engine is started.
I'll record the sound next time I'm in it.

As far as the fuel pump goes, the is an initial buzz when you turn the engine on, then a different constant sound with the engine running. I think this is normal.

Something moving in the tank sounds quite possible. It's as though something that turns is tapping the side.

My 92 has a K-jet instead of the Digi now. Is it possible that it's the same relay issue?

Why would it be a possible relay failure out of interest

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nicci21paul said

Why would it be a possible relay failure out of interest

Briano said he had encountered something similar.



Okay…

I've attached an audio file. It might be hard to hear with headphones though.

Note there is someone sawing in the background.
You can hear one "bong" as pump goes before the engine is started.
Then as the revs start to settle, it starts doing it repeatedly.
The mic is near the back seat, so you can hear it quite clearly.

start.mp3

year would be nice to know and the injection type or carb.

Car is 92, but engine is running k-jet from a 16v mk2.

Does it do it every time you start, ie hot or cold? Could it be the exhaust warming up?

the_whip said

Car is 92, but engine is running k-jet from a 16v mk2.

What is the difference between mk1 and mk2 k jet ?

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If you take the base of the back seat out and get to the fuel sender, start the car and if the noise happens unplug the electrical connector on top of the tank, the car will still run without the lift pump working and if the noise stops the problem could be your lift pump.

jakethepeg007 said

Does it do it every time you start, ie hot or cold? Could it be the exhaust warming up?

Interesting thought. It happens when the ignition is turned on though.

nicci21paul said

What is the difference between mk1 and mk2 k jet ?

ISV and ECU?

mark1gls said

If you take the base of the back seat out and get to the fuel sender, start the car and if the noise happens unplug the electrical connector on top of the tank, the car will still run without the lift pump working and if the noise stops the problem could be your lift pump.

Great idea. I can test it without opening exposing the inside of the tank.

the_whip said

jakethepeg007 said

Does it do it every time you start, ie hot or cold? Could it be the exhaust warming up?

Interesting thought. It happens when the ignition is turned on though.

nicci21paul said

What is the difference between mk1 and mk2 k jet ?

ISV and ECU?

mark1gls said

If you take the base of the back seat out and get to the fuel sender, start the car and if the noise happens unplug the electrical connector on top of the tank, the car will still run without the lift pump working and if the noise stops the problem could be your lift pump.

Great idea. I can test it without opening exposing the inside of the tank.

i do not have an isv or ecu as such

Does it with the lifter pump disconnected :/

Interestingly, the car doesn't start well the first time. After it has run for 30secs-1min, it will start instantly without making the strange sound.

Okay…

I disconnected the 5th injector, and now it starts fine  

Does that mean it's running rich?