Anyone replaced there fuel Pump??

Joined
15 October 2001
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489
Location
Provo, UT
I did a search but didn't find my exact question answered.

In the manual it says to replace the fuel pump you have to drop the fuel tank, but yet there is a access cover and all behind the driver seat to the pump. The manual says nothing about doing it this way so I can only assume that you can only access the top of the pump and can't actually get down to it, but I know on my S2000 the manual talks about droping the gas tank yet when I got back there to do it I just removed the top fuel pump cover and out it came.

So the question:

Do I have to drop the tank like the manual says or can I change out the pump from behind the drivers seat by taking off the fuel pump cover?

J. R.
 
I did replace the fuel pump a while back and wondered the same thing: to do it right you MUST pull the tank. I don't know why they put the access cover where they did....mostly useless.

The cover is over the fuel tank SENDER, not the pump.

Fortunately, removing the tank is an easy, but dirty, job. The tank is very light.

Drew
 
*their* not there
 
You guys who have replaced the pump, did you do it because it failed, or as a preventive measure? If it failed, how many miles did it have on it? If as a preventive measure, what was the reason (noise, current draw, low pressure, etc)?
 
I have done it on a CTSC car with 45K miles. But, remember this config has the voltage stepper to raise fuel pressure. I cannot definitively say that was the cause. Even though the fuel pump is rated at 24 volts (that is my understanding), the step up could have contributed to the early failure.

I do not consider this a common problem, that is the only one I have changed.

Regards,
LarryB
 
I replaced mine several months in advance of a CTSC install.

My car had ~100K miles on it at the time. There was a noticable increase in power, so the pumps DO wear out. I recommend pumps be changed as part of the 90K service....you're losing HP otherwise.

Drew

Note: I replaced the pump with a walbro that wanted me to clip the OEM harness, which is something I am loathe to do. The OEM pump is incredibly over-engineered the quality is incredible---it took some 45 minutes with a 12 amp sawzall to cut the pump apart and recover the OEM threaded connectors from the pump.
 
J.R.,

You will have to drop the tank to replace the pump. The access panel just makes it easy for you to unplug the sender.
 
I just did mine a couple of months ago as preventive maintenance. A few comments:

1) Yes you have to remove the tank.
2) The 6P (?) connector as shown in the manual is located behind the driver’s seat panel. Pull the panel behind the drives seat and you will see a round cut out. Pull the insulation back and you will see the fuel pump wires. Follow the wires to the connector. That is the 6P connector that they talk about in the manual.
3) Helpful tip…once you have disconnected the 6P connector, zip-tie the wire and connector together and place it through the 6” hole. You are probable thinking there is now way it will get hung up, but unless you have someone around who can sit in the car to make sure that it does not get hung up, then I would use the zip-tie trick.
4) Prior to placing the car on jack stands, you will want to disconnect all hoses from the top of the car. This is the hard part and the part that will slow you down. The hoses are going to be hard to get off, but if you use a very small flat head screwdriver, you can push it between the hard line and the hose to break the seal. Once you have broken the seal about 60% around, you should be able to grab the hose with your hand and twist it to free the hose from the hard line. Once you can twist the hose on the hard line it is very easy to twist it back and forth are work it off the hard line. After the install I went to the store and bought a set of hooks. They look like dental hooks with a screwdriver handle. If you have a set, they might come in handy too.
5) The hose clamps are kind of hard to access. You will need an assortment of different size pliers to help you get to them. Nothing special, just a few different sizes. The large pliers don’t fit real well in the tight space. I also remember that I had to slide the hose clamps towards the hard line and not further onto the flexible hose which I was trying to remove. Just play with it and you will figure it out. I also removed the Air Box and took that round black canister off its holder (but did not remove it) so that I would have a little more working room when removing the fuel fill hose.
6) You will need 2 new crush washers for the fuel return line which will be removed at the fuel filter. If you have not replaced your fuel filter, do so at this time. When removing the fuel return line from the fuel filter you will find that the fuel filter will try to turn, a 21mm open end should be used to brace the fuel filter. If you look at where the lines connect to the fuel filter, and use your fingers to feel under the hard lines, but on top of the fuel filter, you will be able to figure out where the 21 mm open end goes. If you have a new fuel filter in your hands you will immediately see where it goes. You get the point.
7) If I remember correctly you will also need two (maybe even 4) new crush washers when connecting the fuel line back to the new fuel pump?
8) Car up on jack stands now, drain the fuel tank. I put my car just high enough to fit a gas can under it with a funnel. Be sure to buy a replacement crush washer for the fuel drain plug.
9) You will need a deep socket for the tank strap bolts.
10) You will get them completely removed and the tank will still be stuck to the car. Just push and pull a little and it will come free.
11) When re-installing, if doing it by yourself, use a jack to help hold one side of the tank in place while you are working on re-installing the straps.


In general it was pretty easy and strait forward. Like all bolts on this car, they come off like they are suppose to and go back on with no problems. You should not run into any trouble. Just don’t under estimate the time it is going to take…I love how the manual describes the procedure on one page in 5 steps, lol. :rolleyes: Hope this helps.
 
What are the signs of a worn fuel pump? I have an aftermarket fuel pressure gauge and the max fuel pressure is always the same, around 360kpa
 
What are the signs of a worn fuel pump? I have an aftermarket fuel pressure gauge and the max fuel pressure is always the same, around 360kpa

Like any other brushed motor, as the pump wears it will draw more current and eventually get weaker. I'm a firm believer in preventive replacements...before you notice the inadequate fuel pressure, the current draw of the pump can be problematic, at least on some cars. Seems the relays may be the only thing at risk on the NSX (maybe hastening their failure?). On my sedan an old pump can burn out the controller, which costs around $400.
 
Based on Larry's input and the lack of failures on Prime, I wouldn't expect to have to worry about it until well past 120k on a stock car (150k? 180k?). Important to watch for though, as a marginal pump can cause a car to run lean and can be easily missed...pressure is fine at idle or no load, but drops off at WOT in gear. Interior gauges can save engines.
 
Hi,

I had a main relay failure last week. The problem was intermittent operation of the pump. Car keep on going dead at odd hours. Replaced n it is working OK but with set of new problem ie when weather is hot the car need to be cranked couple of time's before the engine idle's normal.

I measured idle the input voltage at the fuel pump black/red wire and it was 8.2v, is this correct ? When I start driving the NSX, voltage jumps to 8.6v Does the voltage varies by car speed ?

Need asst. Thanks

T-R
 
The fuel pump system has a resistor in series with the pump. It limits the current to the pump during normal operation, then just before you go to VTEC engagement the resistor is shunted to step the current up to the fuel pump.

The resistance will have a voltage drop across it when current is flowing. I do not recall the exact spec, but I would expect a lower voltage then +12 at the pump when it is in use.

Download the service manual on the home page. Good reading:).

HTH,
LarryB
 
Thanks for the explaination Larry.
I have a manual with me n have gone thru the page 11-99 ~ 11-108 but there are nothing mentioned on the voltage range expect for the sentence "Is there battery voltage?" on page 11-107.

Anyway I have replaced the Fuel filter (same as Civic SH4).
I remember seeing in one the threads on issue's with the "Ignition Switch" contact. Considering to look at this area as the symptom are very similar ie RPM shots up and drops down like brick before engine going dead and I hear a lot of relay clicking during the process.

Let me know if U have any further lead .

Thanks and cheers

T-R
 
"Battery voltage" is exactly that. It's the same ~12.6V that can be measured at the battery.
The small change in voltage @ the pump you saw was from the higher charging voltage (higher RPMs).
 
Took out my ignition key assy just now around 8pm and noticed black soot on the rotary key side and wire contact side.
Used Motul contact cleaner and manage to brush them off. Applied Corning silicon grease and assy. back.
Result very good. Starts at first crank every time and the relays dont click too much. The ignition switch harness is not hot anymore.
I will monitor for a week and post my final verdict.

Thanks for the tip

T-R
 
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