Jump to content

Recommended Posts

Posted

Hello everyone

The other day I was driving. No issues then came to a roundabout and car stopped and wouldn't turn back on.

 

Turned out the ecu power wire had come apart.

 

Anyways soldered that back together and now my fuel pump won't turn on.

I have my fuel pump on by a switch that I installed and I have never had a problem.

Checking the voltage... with the positive and earth on the switch it was reading 12v however when I introduced the fuel pump wire to the switch the reading goes straight to 0v which is very strange

It gets stranger....

If I take the fuel pump power wire (which I used on the switch) and put it straight to the positive battery terminal (which is in the boot) the pump starts up no issues...

 

What could be causing this?

Thankyou

Posted

Maybe a relay or fuse, that's why direct to battery works.

2002 Porsche C2 996 3.6 
1991 Nissan 300zx TT Project

1995 Nissan 300zx TT Crashed 🥲

1997 Jaguar XK8 Scraped ☹️

Posted

There is the small fuse box next to the drivers side firewall, you can swap the interior seats and windows fuse to the fuel pump to check if its blown.

Posted
Just because it worked doesn't mean it was right. Does your switch have any function other than cosmetic?

 

The reason I put it in is so it would be harder to steal if anyone wanted a free zed haha

Posted
Maybe a relay or fuse, that's why direct to battery works.

 

It's wouldn't make a difference because it goes straight to the battery through a switch. All I am doing is losing the switch and it works

 

- - - Updated - - -

 

There is the small fuse box next to the drivers side firewall, you can swap the interior seats and windows fuse to the fuel pump to check if its blown.

 

Looking at those fuses they all look good but it's worth a check mate :)

Posted
It's wouldn't make a difference because it goes straight to the battery through a switch. All I am doing is losing the switch and it works

 

- - - Updated - - -

 

 

 

Looking at those fuses they all look good but it's worth a check mate :)

So straight to the battery it works, but from the battery through a switch doesn't work. Isn't it a given to just get a heavier duty switch or just bypass the switch.

Posted

When you test a supply voltage with no load present you can get a 12v reading, but as soon as you introduce a load onto the circuit the voltage will disappear if there is a poor connection somewhere.

 

You need to check where you took your 12v+ supply from to supply your switch. that could be faulty on the supply side of the switch or your negative supply could be poor with a Load on the circuit.

 

It can be beneficial to use the old fashioned 12v incandescent test lamp as this will introduce a load on a circuit and give better indication of a good supply, modern day led test lamps draw such a low current that they can light up showing voltage when in fact there isn't

 

Test meters can show voltage too but when a load is imposed it will disappear.

Posted
So straight to the battery it works, but from the battery through a switch doesn't work. Isn't it a given to just get a heavier duty switch or just bypass the switch.

 

The switch is 20amps which is plenty. And if I put it straight to the battery then it would be on constant.

The other reason I did it was my fuel pump ecu broke so I had to bypass it. I have a aem fuel pump so I wasn't bothered about the constant voltage as I knew it could take it.

Posted
When you test a supply voltage with no load present you can get a 12v reading, but as soon as you introduce a load onto the circuit the voltage will disappear if there is a poor connection somewhere.

 

You need to check where you took your 12v+ supply from to supply your switch. that could be faulty on the supply side of the switch or your negative supply could be poor with a Load on the circuit.

 

It can be beneficial to use the old fashioned 12v incandescent test lamp as this will introduce a load on a circuit and give better indication of a good supply, modern day led test lamps draw such a low current that they can light up showing voltage when in fact there isn't

 

Test meters can show voltage too but when a load is imposed it will disappear.

 

Thank you mate I will try the supply line.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

Terms of Use