MAJOR FUEL ISSUES 25det neo r32

[25debt]

Hey to anyone that reads this, long time lurker first time posting, sorry if it’s been answered before but I’ve been looking for nearly a year now for answers.

ive got a 25det neo in an r32 that works awesome when it works (made 500whp on 21psi) but works 45% of the time, 1st issue there’s a harness that runs under the passengers side front fender that my tire keeps rubbing through and one wire seems to power the fuel pump even though I’ve done the relay “mod” some people like to call it, and when it does rub through it kills the car, yes next time I’m with the car I want to take the fender off and try tuck the harness well out of the way but I’d also like to try and by pass this mysterious wire as well lol, also wouldn’t mind getting power from the alternator as I’ve read it supplies the pump with 13v ? But no idea where to run the power wire too.

2nd issue, when replacing my fuel pump and fuel hanger I managed to break the factory fuel level sender leaving me with no fuel gauge, I’d like to buy the fpg fuel level sender for r32/s13 but the plug it comes with confuses me, I’ve got a detschwerks x1 fuel hanger which has light + pump - level + pump + and a ground, I’m no auto sparky but I’m wondering if I can cut the plug off the fuel level sender and wire the negative to the pump negative and wire the positive to the level positive to get a fuel gauge back ?🥴

3rd and final issue, the reason I want a fuel gauge is because whenever it’s below half a tank, it fuel starves like crazy and runs like a bag of shit even without doing a pull or sloshing the fuel round in the tank, I’d also like to fix this but have no idea what’s causing it, I’ve got a dw420 and a dead head fuel setup meaning the fuel is regulated before it gets to the engine, my only theory is that the return line is to close to the pickup on the pump and when it’s at half a tank the return line is causing the pump to cavitate enough to cause fuel pressure issues, that or the pump isn’t low enough in the tank which I would find strange considering I can’t find a single thing online about it, also if ya wondering how I figured out it happens at half a tank without a fuel gauge, I waited until it started happening and went and filled up and the car took exactly 30 litres every time I tested it, if ya managed to read through this mess I appreciate that and any recommendations , cheers

[Murray_Calavera]

1 hour ago, 25debt said:

ive got a 25det neo in an r32 that works awesome when it works (made 500whp on 21psi) but works 45% of the time, 1st issue there’s a harness that runs under the passengers side front fender that my tire keeps rubbing through and one wire seems to power the fuel pump even though I’ve done the relay “mod” some people like to call it, and when it does rub through it kills the car, yes next time I’m with the car I want to take the fender off and try tuck the harness well out of the way but I’d also like to try and by pass this mysterious wire as well lol, also wouldn’t mind getting power from the alternator as I’ve read it supplies the pump with 13v ? But no idea where to run the power wire too.

Strange your posting about this being an issue. Move the harness or change your wheels or run more camber etc. Have the thing not touch the thing so it doesn't destroy the thing. 

1 hour ago, 25debt said:

2nd issue, when replacing my fuel pump and fuel hanger I managed to break the factory fuel level sender leaving me with no fuel gauge, I’d like to buy the fpg fuel level sender for r32/s13 but the plug it comes with confuses me, I’ve got a detschwerks x1 fuel hanger which has light + pump - level + pump + and a ground, I’m no auto sparky but I’m wondering if I can cut the plug off the fuel level sender and wire the negative to the pump negative and wire the positive to the level positive to get a fuel gauge back ?🥴

Short answer, no. Slightly longer answer, the factory fuel gauge is measuring resistance. You need to wire in the FPG fuel level sender into the original factory fuel level sender wiring. 

1 hour ago, 25debt said:

3rd and final issue, the reason I want a fuel gauge is because whenever it’s below half a tank, it fuel starves like crazy and runs like a bag of shit even without doing a pull or sloshing the fuel round in the tank, I’d also like to fix this but have no idea what’s causing it, I’ve got a dw420 and a dead head fuel setup meaning the fuel is regulated before it gets to the engine, my only theory is that the return line is to close to the pickup on the pump and when it’s at half a tank the return line is causing the pump to cavitate enough to cause fuel pressure issues, that or the pump isn’t low enough in the tank which I would find strange considering I can’t find a single thing online about it, also if ya wondering how I figured out it happens at half a tank without a fuel gauge, I waited until it started happening and went and filled up and the car took exactly 30 litres every time I tested it, if ya managed to read through this mess I appreciate that and any recommendations , cheers

I drew you a picture to explain this one

The factory strainer is quite long, reaching down into the bottom of the tank. Safe bet your aftermarket fuel pump has a little baby sized strainer that probably doesn't even point down towards the bottom of the thank. 

Solution, move the pump lower down in the tank, or fit a longer strainer, or do both. I did both, I've run my tank down to 5L remaining and the car still drove fine. 

 

[25debt]

 

12 hours ago, Murray_Calavera said:

Strange your posting about this being an issue. Move the harness or change your wheels or run more camber etc. Have the thing not touch the thing so it doesn't destroy the thing. 
I know I know it sounds like a silly problem to have, as I said it will be the first thing I do next time I get a chance to work on the car, I was more or less giving context to the problem wire, as I think I’ve read somewhere that the running a relay is supposed to bypass the factory fuel pump control module or whatever the hell it is.

Short answer, no. Slightly longer answer, the factory fuel gauge is measuring resistance. You need to wire in the FPG fuel level sender into the original factory fuel level sender wiring. 
sorry I should’ve explained this better, the factory wiring is wired to my fuel hanger, but it’s only a single wire, where as the fpg fuel level sender comes with 2 wires and a plug ?

I drew you a picture to explain this one

The factory strainer is quite long, reaching down into the bottom of the tank. Safe bet your aftermarket fuel pump has a little baby sized strainer that probably doesn't even point down towards the bottom of the thank. 

Solution, move the pump lower down in the tank, or fit a longer strainer, or do both. I did both, I've run my tank down to 5L remaining and the car still drove fine. 

Awesome cheers for that I will look into it, just in case I don’t find anything for it, is there a better strainer you can buy that would fit most pumps? Hopefully I can figure out how to lower the pump myself, cheers

 

[25debt]

Also this may be a stupid question, but how would you recommend getting the strainer on a downwards angle ? as they tend to obviously clip to the bottom of the pump which usually sits level 🥴

[GTSBoy]

The smart thing is to actually locate the pump at the right point down the hanger, so that the strainer can stay sticking out at a right angle, but near the bottom. This is the perpetual hassle with retrofitting any different pump to the factory hanger. Some just go where you need it to, some need fiddling and faffing, and modifying of stuff.

[Murray_Calavera]

25 minutes ago, 25debt said:

Also this may be a stupid question, but how would you recommend getting the strainer on a downwards angle ? as they tend to obviously clip to the bottom of the pump which usually sits level 🥴

As GTS mentioned, it takes a bit of faffing, some fiddling and a little modifying. 

With the strainers, you can buy different styles. Some sit flat on the pump, some angle down. 

Here are some photos of mine, ignore the ugly welds lol. 

[25debt]

1 hour ago, GTSBoy said:

The smart thing is to actually locate the pump at the right point down the hanger, so that the strainer can stay sticking out at a right angle, but near the bottom. This is the perpetual hassle with retrofitting any different pump to the factory hanger. Some just go where you need it to, some need fiddling and faffing, and modifying of stuff.

I actually have an aftermarket hanger, the detschwerks x1 hanger, but my dw420 has never really sat in it correctly, good to know I can just modify it a bit to suit.

50 minutes ago, Murray_Calavera said:

As GTS mentioned, it takes a bit of faffing, some fiddling and a little modifying. 

With the strainers, you can buy different styles. Some sit flat on the pump, some angle down. 

Here are some photos of mine, ignore the ugly welds lol. 

Yeah cheers man will definitely have a play with it and hope it solves my dramas.

[GTSBoy]

There's nothing that some paddle pop sticks and extra cable ties can't fix.