12v fuel pump mod questionability

Well its not often I post in here guys but thought I would give you something to mull over.

About 3/4 years ago I had a Walbro pump fitted and then not long after I had the 12v fuel pump mod done after seeing it was recommended. Thing is my fuel pump kept blowing a fuse the other week and it turned out the fuel pump was dead, so dead, it had melted part of the connector and even parts of the fuel pump housing looked like it has melted, basically it looks like the whole fuel pump has got so hot its started to melt in places.

Now this is worrying given its location. But I was adament the cause of the fuel pump fuse wouldnt be the fuel pump itself as these very rarely fail in my opinion and even less so if the pump is only a couple of years old.

Now this has got me thinking obviously my fuel pump is whinning away at a full 12v, which now that I know more, I dont think it really has to be, so why is this advised.

And is it advisable to run a pump constantly like that?

I currently have a 10 year old UK fuel pump in place for now, but Im worried the same might happen to this pump or even worse it goes bang

I will take some pics and get them up for you of the fuel pump in question.....

The 12v mod was never a good idea IMO. You're best off removing it. Sounds like you had a luck escape.

The 12v mod was never a good idea IMO. You're best off removing it. Sounds like you had a luck escape.

So why the hell is it advised so much, especially in a place like this........

So why the hell is it advised so much, especially in a place like this........

I didn't think it was here. Maybe a few years ago.

It's just not needed and, more importantly, dangerous having the pump on constantly when the ignition is switched on.

I didn't think it was here. Maybe a few years ago.

 

It's just not needed and, more importantly, dangerous having the pump on constantly when the ignition is switched on.

Of course it was here lol, this is the only place I know Well yeah granted I have been around for a few years now......

But I did notice in the beggining how the fuel pump could be heard when the ignition is on and thought that has to be stressfull for it, so I never generally left my ignition on while the engine wasnt running, for that reason.......but isnt the pump constantly on when your ignition is on anyway, its just on in 8v mode while the ignition is on. The pump will be always be on when ever the ignition is one depsite what volts its receiving no ?

Whats more worrying is the 12v mod is still in place, sods fooking law the car will explode now before I get chance to reverse it after the car is finally at a stage Im happy with

I did say (Not helpful really that comment is it..)

I'm on my 2nd walbro for this very reason after 2.5 years of running the 12v mod I think its time to change...

My first pump melted just as you described in your first post.

So, looks like I need a new fuel pump relay, part number anyone? (fuel pump relay in the passanger rear quarter panel stopped working for some reason which is why I did the 12v mod)

Since I joined the forum I have always got the message/impression that the 12v mod was not a good idea

So why the hell is it advised so much, especially in a place like this........

I advised about this mod years ago. To not do it, stating the reasons why...

Ive never done it, neither used a walbro pump, although I did buy one but never fitted it....my upgrade was a denso UK spec pump and im going to drop that straight in and leave the wiring as it is

I also thought 12v mod was a bad idea.

Interesting that its melting the pump though, does the fuel pump ECU regulate current as well as voltage then?

This asside the pump should be able to handle a constant 12v, since with the car running the voltage can be closer to 14.4v it should also handle this without issue.

Have you changed the wiring to the pump?

if it cant handle 12v continuously in a supra then how can it do it in other cars, from what i read the supra is one of the only cars that uses this 8v-12v system with its fuel pump

if it cant handle 12v continuously in a supra then how can it do it in other cars, from what i read the supra is one of the only cars that uses this 8v-12v system with its fuel pump

I agree, most fuel pumps should be rated 12v and 14.4v.

The fact things are melting looks like a current issue.

I agree, most fuel pumps should be rated 12v and 14.4v.

 

The fact things are melting looks like a current issue.

So as you said Wez, the fuel pump ECU might regulate current as well as voltage?

Anyone have the part number for a new fuel pump ECU?

I agree, while it should not cause any problems, a lot of other cars run permanent 12V to pump, i can't help wondering if its down to the pump ECU developing a fault.

Well I had to tempt fate didnt I, she broke on me tonight, was driving along and it felt like a pop, my first thoughts were "Ahhh shoots there goes my tubby blades".....but she still making boost, while very lump'ily trying to move along. I pulled onto the hard shoulder and she died. I started her up, she fired up fine but then runs really rough. It reminded me of the time my MAF sensor on the S13 was sending dodgy signals and the ECU was trying to compensate with the fueling, so a bit like that, rough and lumpy. Anyway she would start but die without holding her idle.

I have talked to a few and considering she very rarely breaks down, and this fuel pump issue, I think she may have eaten another fuel pump. I think the pump is working enough to pressureise the rail to fire her up but then not enough to keep her going.

Had to be recovered back by the AA, and with the genuin Ridox front cant even find my tow eye, so we used the strut brace to winch her on, but it bent under the strain, still that wasnt my main worry, the £900 Ridox front and carbon fibre lip was what was worrying me getting her on the flatbed. A £70 strut brace I can cope with lol..........fun and games

Will get the pump out tomorrow and have a look, oh and get someone to reverse the 12v mod quickly.....

Just heard from Ash, and it wasn't the fuel pump , damn over the phone diagnosis

So as you said Wez, the fuel pump ECU might regulate current as well as voltage?

 

Anyone have the part number for a new fuel pump ECU?

Got a spare here worked fine in the car up to February, when it was taken out for going big single car.

Just heard from Ash, and it wasn't the fuel pump , damn over the phone diagnosis

No it wasnt the fuel pump, and Im really ashamed to say this, because its a school boy error with these cars and after 7 years ownership and it happening to me before previously I should have realised what the problem was..........

That classic boost pipe popping off Shame I know have a bent strut brace for it though, but still at least I havent got to start solving problems.......I will be getting the 12v reversed asap though.....

Imagine if the Ridox was damaged for a pipe off

Imagine if the Ridox was damaged for a pipe off

Makes you shudder dont it lol, but thats all I was thinking while sat on the hard shoulder, how is the Ridox going to fair getting winched on, so after getting the car on and off without a hiccup and the strut brace bending I was and still am actually happy, I mean I can get another strut brace for £70-£100, but yeah there was only mm to spare.

It was a nice surprise though finding out that that carbon fibre lip aint just a lip, its part of the under tray that goes all the way back, so that makes it ten time stronger and nice knowing thats why that bumper costs what it does. Im never going back to copy kits

I know this is technical section (sorry) but, I'd like to see a photo of the undertray section the Ridox, the next time you have it up off the ground

Well this story certainly continues.....

Put the boost pipe back, Gav came round and reversed the 12v fuel pump mod, started her up and she runs for a few seconds then the ECU is shutting the fuel pump down and killing the car.

We figured out why the blown boost pipe appeared to be the issue as we think what happened on the motorway, the ECU has picked something up and closed the throttle body and shut things down, this would have caused a bit of build up as the turbos still sping increasing the pressure too much and a pipe blew.

We have checked the fuel pump relays, they are good, Gav tested the fuel pump by priming it manually and running a direct feed to the fuel so the ECU cant shut it down and the car runs, but for some reason under its on power the ECU is picking something up and killing the power the fuel pump ?

Any idea's.....?

Gav is coming to come over Sunday and test all the electrics of the car end to end to check the wiring hasnt been compromised somewhere, then it could be the alarm killing the power but dont know if this would kill the power then or how it does it, apart from those two things we cant think of anything else.....

Did you start the car after putting the boost pipe back on and BEFORE reversing the 12v mod?