Fuel pump relay

[gcon45]

I've noticed an audible random clicking when idling (or coming off the throttle) behind the passenger seat.

From memory this is where the fuel pump relay is housed.

I also noticed on idle that there seems to be a high pitched whine coming from the engine bay that definitely wasn't present previously.
(This is most likely to be happening all the time but is only audible with the engine idling).

Could it be that my relay is faulty and it's not activating the low rev pump leaving the secondary pump to do all the work?

I ran the car as low as I could on fuel before winter storage as I wanted to use up as much of the fuel present in the tank as possible so as not to let it sit and stagnate. I've put in about 10L of fresh BP Ultimate since. I'm wondering if running the car so low on fuel has in some way caused this.

There are no warning lights on the dash and the car drives 100%.

Any thoughts?

[Kaz-kzukNA1]

Hi, gcon45.

From lots of your other posts on here, your NSX is face lifted model so it's DBW.
I believe it's the RHD model.

The Main Relay is behind your right shoulder near the seat belt panel on the DBW model so if you are hearing the clicking noise behind the passenger seat (left side), then it’s not the Main relay.

Although it says 'Fuel pump relay', it’s actually a Fuel pump 'high speed mode' relay and only activated when you first turn the IG key into P2 ON position for 2sec, while cranking the engine or under high engine load.
Thus, it is not activated at the idle rpm or when you are coming off the TH.

What is the voltage reading when this clicking noise happens?

In fact, if you can hear the clicking noise even at idle rpm, why not just remove the upper rear panel and listen to the clicking noise while placing your fingers on some of the relays?
You should be able to identify the source of the noise if it's indeed coming from one of the relay.


Regarding the whine noise, does it change when you switch ON and OFF the a/c compressor?

Please make sure to confirm that your compressor is engaging when you press the a/c On switch because around this time of the year, you may not be able to engage it if the evaporator temperature is too low like 4degC.
This is not the outside temperature but the evaporator body temperature and it will be at very low temperature if you ran the a/c for a while.

The a/c idle pulley is known to cause squeaky/whine noise. It's not always the case but in the past, I managed to diagnose the faulty a/c idle pulley bearing by the above method.
Ultimately, you need to remove the belt and spin it by hand or remove the pulley together with the bearing and just inspect the actual bearing for any rattle.

Fuel pump will make whine but I don’t think you can hear it while running the engine.
You can try bypassing the fuel pump resistor inside the engine bay by activating the above fuel pump relay to see whether it will change the whine pitch or not.

There are other possibilities such as ACG bearing, loose TB tension, etc.

Does the whine follow the engine rpm?


There is no such thing as secondary fuel pump on our NSX.
ECU doesn't have fuel pressure mapping for EFI control and it just relies on the pressure regulator to set the fuel pressure always at 3.5kg/cm2 higher than the intake manifold pressure.

You can ran the engine even with just 3L left in the tank as long as no high G applied or without steep angulation so 10L is well enough.
When there is only like 3L left, the low fuel warning light stays On all the time regardless of angulation or G and your fuel level gauge sits almost like at the lower edge or even below the empty line.

If you ran the INJ dry, it will damage it but won't cause whine.


Kaz

[gcon45]

Thanks for the reply Kaz!

Ah so instead of there being 2 pumps there is 1 pump with 2 modes.

The whine isn't the AC as its there whether the AC is on or not.

I will take the panel off to see which relay is clicking and report back!

Thanks again.

[gcon45]

Kaz - clicking and whining has disappeared!

I wonder if it was just a electrical gremlin with the car being in the air chamber for almost 6 months?

[gcon45]

Another update!

The relay click and engine bay whine have subsided but as unclebob alluded to via PM it may have been a fore bearer for bigger problems.

My voltage gauge is running at or slightly below 12V with the engine running now.
It usually runs around 14-15V so it looks like I have alternator issues.

I've also got what's been confirmed as a steering rack bush total failure.
It's been squeaky for a year or so and having sent D1 guy on Prime a video of me moving the steering manually whilst on the lift he has agreed.

It's $1500 to recondition the rack (plus shipping to US).
I'm either going to do this or buy a manual rack.

Ive had the car over 6 years now and the only thing I've ever had to replace is a brake light bulb!

Ah well...

[WhyOne?]

Hi. I had precisely these symptoms about 2years ago (whining and clicking) - a new alternator (sourced from the USA) was the solution.

Sorry to hear about your steering rack problem.

[Kaz-kzukNA1]

Hence, my original question above - ‘what is the voltage reading when this clicking noise happens?’

Over the last 6 months, how did you look after your battery?

Did you disconnect it off the car and kept it on the battery conditioner?
Did you keep it connected on the car with the battery conditioner?

How did you start the car this time? With healthy battery or did it fail at the first attempt?

What make/model of battery conditioner do you use?

Did you jump start the car over the last 6 months and if so, what car model did you use and how did you do it?
Have you ever jump started the car without connecting the battery or have you ever disconnected the battery while the engine was still running?

How is the condition of the battery at the moment?


Kaz

[gcon45]

Thanks for the replies.
I've had it connected 24/7 over the winter to my CTEK MXS5.0 smart charger / conditioner in situ Kaz.
It's never been jumped, leads were never removed with engine running and the battery starts the car first time.
I've tested the battery. CCA and voltage is 100%.

[Kaz-kzukNA1]

I believe you haven’t used the battery re-condition mode while the battery was still connected to the car.
Having said this, when the car is powered off (IG sw in P0, OFF position), although the ACG is connected to the battery, the IC Reg is not even powered up and the Rectifier is doing nothing as it’s DC and not AC.

As your battery is tested fine and never jump started, it didn’t cause the huge surge at the ACG.
Based on your test, the battery itself is fine and no other electrical failure (except the EPS below) and still looks like you somehow managed to kill the ACG.

Based on your email, I was worried about your EPS rack internal failure. As recommended, please check the rackend boot.

Have you seen EPS warning light?


Kaz

[gcon45]

I believe you haven’t used the battery re-condition mode while the battery was still connected to the car.
Having said this, when the car is powered off (IG sw in P0, OFF position), although the ACG is connected to the battery, the IC Reg is not even powered up and the Rectifier is doing nothing as it’s DC and not AC.

As your battery is tested fine and never jump started, it didn’t cause the huge surge at the ACG.
Based on your test, the battery itself is fine and no other electrical failure (except the EPS below) and still looks like you somehow managed to kill the ACG.

Based on your email, I was worried about your EPS rack internal failure. As recommended, please check the rackend boot.

Have you seen EPS warning light?


Kaz

No Kaz the CTEK was only ever used in standard mode - not recon.
Is it usually just the regulator part of the alternator that goes faulty in these and if so; is it possible to buy the regulator separately?

I have no EPS warning lights, just a screech when turning the steering. It's been like this for almost a year and a half now though and the sound is coming from inside the rack. As I was saying I sent the same video clip to D1 guy on Prime that I sent to you and he's convinced it's a bush failure. Boots and clips are fully in tact.

[gcon45]

If worst comes to the worst and I have to replace both the rack and alternator - can anyone confirm that 210-0203 is the Denso alternator part number that covers 95-05?

Also Kaz, I recall reading a post from you recently about the manual steering rack becoming available shortly in Japan.

Do you know if this is the case and what is involved in converting from EPS to manual?

[NSXGB]

RockAuto worth a look on the alternator or maybe just the parts to fix.

[unclebob]

Yes thats the part number.

[WhyOne?]

If worst comes to the worst and I have to replace both the rack and alternator - can anyone confirm that 210-0203 is the Denso alternator part number that covers 95-05?

.......


Yep - that's what I bought - £144 + about £20 shipping from the US - Denso Alternator part number 210-0203, fitted to my 2001 NA2 NSX.

[Kaz-kzukNA1]

No doubt, Denso car parts are one of the most reliable and top quality in the world.

Modern ACG doesn’t fail for no reason.
It would be interesting to know whether the NSX owners who experienced ACG failure have EPS on their NSX or not.
Not only the lack of electrical capacity at the two relays inside the EPS controller, the commutator at the rotor burns out resulting in massive increase in resistance and annoying noise.
Though, ACG failure is very rare for NSX owners based in Japan and there are about 7,000 out there with lots of EPS equipped ones.
Even some of the NA1 Type-R and NA2 NSX-R owners converted their manual rack to EPS one so you may be able to find used good condition manual rack in Japan.

You could overhaul your ACG like me here (http://www.nsxcb.co.uk/showthread.php?6286-NSX-Health-Check-Service&p=75266#post75266) but if you can get the re-manufactured Denso one at such low price, it’s probably cheaper to just get it than replacing the parts inside.


If you are sure that the noise is coming from inside the EPS rack, then, as mentioned above, it could be the burnt commutator where the brush sits.
Very popular process to have it cleaned during the overhaul.

By the way, US$1,500 for the EPS rack overhaul plus the delivery charge to/from US……

I don’t think there is any big difference between RHD and LHD EPS rack but if you pay that amount and send the EPS rack to me, I'll hand carry it carefully by myself, take the flight to Japan, visit T3TEC, have your rack overhauled while I stay at my home in Japan, hand carry it back to UK and send it back to you.

Joking aside, T3TEC will overhaul it probably less than half the above price and yet because of their EPS rack OH jig using real EPS controller, the owner doesn’t need to do any adjustments after receiving the rack.
Speaking of adjustment, have you ever touched the pre-load? Very unlikely but wanted to check.


Unless you have mechanical failure, you can run your EPS rack without power assist.
Just disconnect the connectors from your EPS controller.
The EPS warning light is low side active through the controller so if there is no power to the controller, it will be open circuit and no lights on the dash.


If you want to replace it to the manual rack, then addition to that, you will need the manual rack spec universal joint but not expensive.
Strictly speaking, the length of the rackend boot is different between EPS and non-EPS one but can be re-used.
You will be forced to replace the locking washer regardless of EPS or non-EPS as you will be asked to remove the rackend before sending it for the overhaul and I think the rackend stopper washer is different between EPS and non-EPS but no big deal.

Hope you can fix your ACG issue very soon and while you decide on what to do with the EPS, you may want to disable it to prevent any unknown factor for the cause of ACG failure or further burning the commutator.


Kaz

[gcon45]

Haha! Thanks again for the replies!

Kaz - I have ordered a new alternator from Denso and will disconnect the EPS as you say just incase the increase in resistance is what is causing electrical problems.

Preload has never been touched.

Do T3TECH offer a rack overhaul service? Where are they based?

[Kaz-kzukNA1]

http://tyiz.jp//NSX/BBS/bbs/data/1428306863.2.jpg

http://tyiz.jp//NSX/BBS/bbs/data/1428306863.4.jpg
They are based in Japan.
https://goo.gl/maps/XhAKXXg79Uo


They offer complete EPS rack overhaul using this jig.

Probably the first place to start offering this service in the world since they already had the know-how even before setting up T3TEC.
Funny enough, Honda dealers in Japan are also using their services for years now.



http://tyiz.jp//NSX/BBS/bbs/data/1450856774.7.jpg
They even developed their own torque sensor I/F circuit board.

I was already discussing with them about bringing their service to here several years ago but the market is just not big enough so it’s at the low priority of my list.

Still, having such wonderful people there is a great relief for those looking for the long term ownership.


Kaz

[All photos are courtesy of Mr Toyoizumi at T3TEC, Japan.]

[gcon45]

Great info Kaz.

I will contact T3TEC.

Thanks again!

[gcon45]

New (remanufactured) alternator arrived from Amazon today.

A few pence under £200 delivered.

The plastic output shroud was smashed to bits though.
Couriers obviously don't handle with care!
http://i1075.photobucket.com/albums/w428/conoroneill/Mobile%20Uploads/image_zps2s3lzuhz.jpeg (http://s1075.photobucket.com/user/conoroneill/media/Mobile%20Uploads/image_zps2s3lzuhz.jpeg.html)