fuel pump

[op012503]

does anyone know the location of the fuel pump in a 2000 altima? Im replacing my stocker with a wahlboro 255 and need some advice on how best to do it

[JustSayGo]

The fuelpump is inside the fuel tank. There's an access cover under the mat in the trunk. There's a metal shield and a smaller cover that must be removed. Relieve the pressure in the tank by loosening the filler cap. Don't let the gas get on the mat when you remove the pump. About half a cup of fuel will drain from the pump. Wahlbro puts + and -- marks on their pump near the electrical terminals. Use a new strainer filter. Most strainers have plastic inside the strainer that will break if you push on the plastic when you push the strainer onto the new pump. Then a tiny little plastic sliver will lock the new pump up. Make sure the o-ring that seals the tank to the sending unit is good. The seal has to hold pressure and vacuum. Fasten the wires to the pickup tube with plastic ties (on each side of butt connectors if used) so vibration won't break the wires.

[op012503]

Originally Posted by JustSayGo

The fuelpump is inside the fuel tank. There's an access cover under the mat in the trunk. There's a metal shield and a smaller cover that must be removed. Relieve the pressure in the tank by loosening the filler cap. Don't let the gas get on the mat when you remove the pump. About half a cup of fuel will drain from the pump. Wahlbro puts + and -- marks on their pump near the electrical terminals. Use a new strainer filter. Most strainers have plastic inside the strainer that will break if you push on the plastic when you push the strainer onto the new pump. Then a tiny little plastic sliver will lock the new pump up. Make sure the o-ring that seals the tank to the sending unit is good. The seal has to hold pressure and vacuum. Fasten the wires to the pickup tube with plastic ties (on each side of butt connectors if used) so vibration won't break the wires.

could the strainer filter get clogged? Im experiencing a lose of fuel pressure when i get on the gas. As far as i know the stock pump should keep the pressure relativly constant.

[JustSayGo]

You are correct. The fuel pump pumps a constant volume. The pressure regulator on the fuel injector rail controls the pressure by controlling the restriction of fuel returning to the fuel tank. Connecting a fuel pressure guage to the fuel rail will tell you if the problem is caused by low fuel pressure. When you accellerate, the manafold vacuum to the regulator drops and the fuel pressure should increase 3-5 PSI. AutoZone might have a loaner guage. With oxygenated blended fuel constantly circulating back to the tank and going through the fuel filter, fuel tanks stay very clean. It is unlikely that the strainer is clogged unless somebody put something in the tank. You are the turbo guy, right? Do you have a fuel guage and aftermarket adjustable fuel pressure regulator?

[op012503]

Originally Posted by JustSayGo

You are correct. The fuel pump pumps a constant volume. The pressure regulator on the fuel injector rail controls the pressure by controlling the restriction of fuel returning to the fuel tank. Connecting a fuel pressure guage to the fuel rail will tell you if the problem is caused by low fuel pressure. When you accellerate, the manafold vacuum to the regulator drops and the fuel pressure should increase 3-5 PSI. AutoZone might have a loaner guage. With oxygenated blended fuel constantly circulating back to the tank and going through the fuel filter, fuel tanks stay very clean. It is unlikely that the strainer is clogged unless somebody put something in the tank. You are the turbo guy, right? Do you have a fuel guage and aftermarket adjustable fuel pressure regulator?

I dont have an adjustable fmu but my af guage goes into the red at wide open throttle. They only time i get any consistency in boost is when i ease in to the throttle.

[JustSayGo]

Is FMU, Fuel Management Unit? As in allows you to adjust and fine tune the engine computer? They can't adjust fuel pressure. AF is A/F as in measures Air Fuel ratio, guage? They don't measure fuel pressure. Can you read fuel pressure while you are driving? What happens if you dissconnect and plug the vacuum hose to the fuel pressure regulator and test-drive? You could raise your fuel pressure with one of these but the fuel pressure will still decrease under accelleration if you connect the vacuum hose. None of the listings cover a 2000.

http://search.ebay.com/Altima-fuel-p...ageNameZRC0022

[op012503]

Originally Posted by JustSayGo

What happens if you dissconnect and plug the vacuum hose to the fuel pressure regulator and test-drive?

Ill try it. Do you know if the fuel injectors are suposed to prime the cylinders when the key is put in the 'on' position? Ive asked the question before and got mixed answers.

Nismo makes a regulator for my car but it doesnt have a guage...

[JustSayGo]

Injectors should not leak under any circumstance when the distributor isn't turning. The same signal from the distributor that results in the spark plug firing also signals the injectors. When you turn the key on, the fuel pump runs for 5 seconds to pressurize the fuel system to the injectors. The fuel pump is turned off by the fuel pump relay after 5 seconds if the engine doesn't have oil pressure. This prevents fuel from being pumped in the event of an accident that causes a fuel leak. If injectors do leak with the key on they are deffective. The Nismo FPR is ugly by comparison at twice the price. I think there are regulators with gauges available that will fit a 2000. Maybe one of the regulators listed will work. You really only need the gauge when you adjust the regulator. I suspect that if you ran at a track, safety tech inspections may require the gauge to be removed and plugged because it is an unnessasary potential fuel leak.

[op012503]

Originally Posted by JustSayGo

Injectors should not leak under any circumstance when the distributor isn't turning. When you turn the key on, the fuel pump runs for 5 seconds to pressurize the fuel system to the injectors. The fuel pump is turned off by the fuel pump relay if the engine doesn't have oil pressure. This prevents fuel from being pumped in the event of an accident that results in a fuel leak. The same signal from the distributor that results in the spark plug firing also signals the injectors. If injectors do leak with the key on they are deffective. Nismo is ugly by comparison at twice the price. I think there are regulators with gauges available that will fit a 2000. Maybe one of the regulators listed will work. You really only need the gauge when you adjust the regulator. I suspect that safety tech inspections may require the gauge to be removed and plugged because it is an unnessasary potential fuel leak.

i dont think im gonna have a problem with a fuel pressure regulator if i need one because in NY they dont check under the hood. I know with a regulater the car will idle like sh!t anyway. My next move is to swap out the injectors for 550cc and change the fuel pump. If that doesnt solve my fuel problem im gonna drive the car off a cliff so if u want a turbo alty its yours
thanks for your help btw. The car is now in storage until this is fixed.