Nissan Repair: NON STOP and Noisy Fuel Pump, 1986 nissan stanza, nissan stanza wagon

Question
QUESTION: I've put in a rebuilt engine, a rebuilt transmission, and new starter and a new distributor recently and had to replace the exhaust gasket when it blew due to a faulty distributor installation. About this time my original fuel pump on my 86 Nissan Stanza Wagon was starting to become noisy (whirring). Changed it. Changed the fuel Filter. Changed O2 sensor. HOWEVER, the new aftermarket pump (Carter) was noisier. Changed that pump with another of the same brand. Still noisy. A different mechanic installed another pump. It was also noisy. Checked Fuel relay. OK.  At this time the pump then continuously started to continue making noise at start-up when key engaged. Mechanic said I now have "an electrical problem"?
It USED to stop making noise after five seconds, per manual specs.  Now it stays running and eventually gets loud so it even drones over conversation!   The fuel pressure check was SEVENTY-TWO PSI. The Nissan recommended PSI is about 36.
Was getting "surging" at start-up on my rebuilt engine and I changed the FUEL PRESSURE REGULATOR which , in this model, is WELDED to the fuel pressure rail - which is quite expensive so I installed a used fuel rail... which seemed to do the job:
the surge on start-up rectified itself with the fuel pressure regulator replacement (I am assuming it is good).

I then replaced the fuel pump FOR A FOURTH TIME and with the replaced Fuel Regulator the pressure  now dropped to 58PSI, but this (fourth) pump is also VERY noisy...it is a used 1986 Nissan Stanza wagon pump.  

The non-stop running sound and the whirring sound is unbelievable!  

I just removed the gas cap and there was an escaping hissing sound (pressure venting) , and, then went to the vapor cannister and removed what appeared to be a fuel return hose  and blew into it and there didn't appear to be any blockage.Another question: IS there a fuel return line on my 86 Stanza wagon???
I am wondering if there is an ELECTRICAL problem and have been reading a little about some fuel solenoid driver/shut-off solenoid. Is THAT why the pump runs on after 5 seconds?  Is that WHY the pump becomes noisy (overworked?).
To recap: I don't have a problem with a pump that doesn't work; it ALWAYS makes loud noise.

THANKS gary crane  email: garycrane@yahoo.com

ANSWER: Gary,

I would do a couple of things here.  First, drop the tank and check the voltage to the pump.  It should not be 12 and should be something like 9.2 volts.  If it were me the first thing is to replace the fuel pump relay since the different pumps give the same noise.  Also, there is a return at the end of the fuel rail so check for blockage or a crushed return line.  This could cause the oper pressure.  But, I still think you have the relay problem.  Email me back with what you find.  On the fuel tank install make sure the tank is not touching in the wrong places since it is such a pain to get in right.  No insulation to speak of either.

---------- FOLLOW-UP ----------

QUESTION: Curious if you really mean  to drop the tank as the pump is EXTERNAL?  I DID change the fuel pump relay and it didn't change anything, in between pumps 2 and 4!  I will certainly check into the return at the end of the fuel rail and wonder what "oper" refers to in your last reply; just a spelling mistake maybe> Can't figure it out.  Having changed the relay before I don't know where to turn?  

Again, the secondary problem is:  pump doesn't stop making noise after 5 seconds per the manual... Someone said that part of the problem is controlled by the EGI Fuel Injection Relay, the green relay NEXT to the Fuel Pump Relay?

By the way a check of the box under the seat gave code 22: fuel pump circuit malfunction before I installed this latest pump....which itself also became noisy after the codes were cleared...with a day or two of installation (same as others). Loud and whirring/droning almost constantly! Thanks!
ANSWER: Gary,

I was trying to type operating pressure with that typo.  The EGI fuel injection relay should not cause the pressure to drop.  I would backtrack the fuel pump circuit and see if there are any shorts since it seems that you have replaced the fuel pump relay.  So, get a volt ohm meter and check the voltage getting the the pump at the relay and see if it starts at 12.2 volts down to 9 volts.  If it is not dropping off then the circuit is damaged.  I would think there is a resistor circuit that is cooked.

---------- FOLLOW-UP ----------

QUESTION: So, is what you are saying is that there is a resitor circuit located BETWEEN the Fuel Pump Relay and the Pump?  Should be 12 AT the Relay and should be 9ish AT the pump? Thanks!

To recap, wonder why that pump doesn't shut-off after first 5 seconds is your guess it keeps thinking it has low pressure (so keeps running?)

This noise is spooky.

Thanks for your respones. I'll get a friend to help on the weekend.  May I reply back after that with what we found?
Gary
ANSWER: Gary,

I cannot find the Australian website that describes the workings of the fuel pump circuit.  I would get a Haynes Manual and start back probing with a volt / ohm meter and start at the back and work to the front until I found the voltage variance.  I am sure there is a cooked part of the circuit since you have replaced the relays.  Email me with what you find.

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QUESTION: I checked at relay and pump and got 12 and 9.
Stupid question: HOW do I check the return at the end of the fuel rail?  To the very very very best of my knowledge there is neither a Chilton or Haynes manual on the Stanza Wagon...I've looked for years.  I have the Nissan Service Manual and it is useless. Very incomplete. Do you have any further suggestion about that Australian website describing the workings of the fuel pump circuit and, IS IT SPECIFIC TO STANZA WAGON?  Totally in the dark...Gary in Vancouver Canada.  Incidentally thought you'd get a chuckle out of this : MY car is actually called a Nissan MULTI. They called the car a Stanza Wagon in the US and it was sold as a Nissan Multi in Canada! I am trouble following your seemingly simple tips.
ANSWER: Gary,

That is good the voltage is correct and to check the fuel return line you could disconnect the return line and install a pressure gauge between the lines and monitor the pressure at return.  I have seen a Stanza manual for yours on-line.

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QUESTION: Thanks. I bought the Nissan Stanza Wagon manual from Ebay. It is not very good. Points to places and leaves you having. No index either, hence I am asking for your expert help.  Or, are you saying you saw a Chilton/Haynes on line....never knew them to exist.

Are you saying to disconnect the return line from the end of the fuel rail?  The last time we did a fuel pressure check it was 58PSI...manual calls for 36. IS THIS TELLING US ANYTHING?  Lost, Gary.  Appreciate your advice, just lost (layman) with a layman assistant, after spending over SIX THOUSAND DOLLARS ON THIS CAR TRYING TO FIX IT MYSELF.
ANSWER: Gary,

If the pressure is too high then there is an obstruction.  To check and see where it is you can get on the other side of the pressure regulator, return line, and if the pressure is still high you probably have a crushed line.

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QUESTION: We got ZERO psi
when the pressure check gauge was placed at the fuel rail on the return side of the pressure regulator.
ZERO psi?  What does that mean?

We know the gauge works as we checked the in line and got 58psi.

What do I need to know next about

1) the pump staying running after 5 seconds when key turned

and

2) extreme noisy drone, like a bee buzzing.

Thank you sir, Gary in Vancouver
ANSWER: Gary,

In checking the fuel pressure you are way over on pressure which leads me to think the return line is crushed going back to the tank.  That is why I was asking the pressure be checked at the pressure regulator and then on the return side of it.  If you disconnect the vacuum line to the fuel pressure regulator does the pressure go up?  Probably not since it is so high.  I bet if you put the car up on jack stands you will find the return line is cruched along the way back to the tank and that is why the pump is screaming since it is working it's butt off for nothing but a massive restriction (crushed fuel line).  Check it out and email me back.

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QUESTION: I've had 3 people think there doesn't NEED to be pressure on the return as it is just a flow return if needed. Are they wrong?
I checked and the line from the fuel rail back has no exterior visual sign of damage.
This is crazy.
Is there a return line from the purge cannister?

How about the little checker box under the seat; do you think it may also be a computer to control fuel mixture etc and I may need to probably replace that?
Going nuts in Vancouver and thanking you for your expertise!
ANSWER: Gary,

You have too much pressure and that makes the pump strain so there will be noise.  If there is not a crushed line then you have a defective pressure regulator or the line that feeds into the tank is plugged.  Too much pressure will give you the noise and get bad mileage as well as kill the pump.  You have to figure out why the pressure is so high.

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QUESTION: What do you mean by "the line that feeds into the tank'?
Are you refering to where I put in the fuel at the gas pump, that line to the tank?
ANSWER: Gary,

There are three lines that connect to the gas tank other than the filler neck.  The three small lines are the fuel feed line (pressurized fuel), the second is the return line that comes back from the fuel rail on the pressure regulator side and the third is the canister vent valve line that feeds to the charcoal canister.  The two that you are interested in are the one that feeds the fuel to the fuel rail and the other is the return line.  I think that return line is plugged up or damaged somewhere between the fuel rail and the the gas tank.  There is a remote possibility that the assembly in the tank has a damaged line or something is plugging it where it feeds into the tank.  Basically, what I am saying is the fuel pressure cannot possibly be as high as you state unless there is something restricting the return to the tank.

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QUESTION: Well I managed to get the car up on a hoist and got a good look and there doesn't appear to be any kind of damaged lines between the pump and the fuel rail.  Pump is as noisy as ever!

Might the computer (checker box) possibly be giving wrong info?

OR??????

Wish I could put you on an airplane!
ANSWER: Gary,

I would not mind the trip if I could.  But, back to the pump.  The fuel pressure is way too high so have you replaced the fuel regulator?  If not, change it and see if the pressure drops.  Otherwise, take the return line off at the tank and get a gallon can and a fire extinguisher.  Have someone turn the key and see what the return flow is.  I know it has something to do with the over pressurization of the fuel rail.  If a pump pushes against a force that is too great it will cavitate and make really loud noise.  Basically, the pump is stalling and that is where the noise comes from.

---------- FOLLOW-UP ----------

QUESTION: Ran a new hose from the fuel rail to the pump. Nothing changed.

BTW yes fuel regulator was replaced (was welded to whole fuel rail).  Fuel came spurting out of the return rail when it was removed and the key turned; is that what you expected?

FUEL PUMP STILL GRINDING/DRONING/WHIRRING/WORKING loudly.

Main PROBLEM: This has to be part of the solution?  When the key is turned on the pump doesn't shut down after 5 seconds per the Nissan shop manual...it keeps running non-stop and loudly.  Gary

Answer
Gary,

If the pump is not shutting down or dropping to the slower speed I would be looking at the ECM as it controls the pump and the relays control the power it receives.  If it is 12 volts all the time there is something wrong upstream where the computer controls the pump.  You could wire around the mess.  A site in Australia showed how to get more power from Nissans by wiring around the computer.  You could get a five second delay relay and another relay and wire them up to duplicate what the computer is supposed to be doing.  Wire them both to switched ignition.  The first gets 12 volts to the pump and the second gets a resistor to drop the power to 9 volts.  Otherwise, check the ECM and see what it is delivering.