Relay click in engine area

[Computron]

Hi,

I'm still a relatively new 2004 NSX owner, so I'm still getting used to the car, but I'm wondering if something I keep experiencing is normal.

When idling, I can occasionally hear a relay click in the engine area behind me like an A/C clutch engaging even though I have the A/C off. Is this normal? Is there an engine fan or something in the engine compartment as well as in the hood area? It is identical to A/C engagement as far as sound goes and you can see/feel the engine take on an additional load like A/C engaging, but I have the A/C off. It just engages for a bit, and then goes off again... then a bit later, back on and then off again, just like A/C.

Any info would be greatly appreciated! Thanks!

 

[dablackgoku1234]

The only "click" I hear in my NSX is when the fuel pump changes over from low speed to high speed at about 4k rpm.

If your AC is kicking in and out (check the condenser fans when it kicks in to confirm) while your AC is set to off, it sounds like you have cracked solder in your rad fan module (37735-PR7-A01). Check this thread: http://www.nsxprime.com/forum/showt...y-I-ve-searched-(?highlight=ac+turning+on+off

 

[arista5]

After i start my car and let it warm up, often i hear a click in the engine area and idle change. Its also accompanied by what sounds like an air pump injection type sound. I had it on both of my 05s and each was/is low mileage. I believe its a common sound

 

[Computron]

After i start my car and let it warm up, often i hear a click in the engine area and idle change. Its also accompanied by what sounds like an air pump injection type sound. I had it on both of my 05s and each was/is low mileage. I believe its a common sound

Yes that sounds like what I'm experiencing. Any idea what it is or what it's doing when that happens? Mine is low mileage as well.

 

[vivanshah]

could it just be the relay for the radiator fans?

 

[Computron]

I guess I am still getting used to how different the NSX is from other cars, but apparently there are 2 condensers and 2 fans that go along with them to run the A/C. These are obviously not in the front of the car where the radiator is and I think they are behind the passenger compartment in the engine area. That's what's confusing me... those should not be the source of the click I hear because my A/C is off and I would think the relay click for the radiator fan would happen in the front close to where the radiator fan is. I guess I need to look to see if the radiator fan starts and stops with the click I hear behind me.

Anyone else have any insight on what I am hearing?

 

[jwmelvin]

The significant clicking that I hear is from the fuel-pump relay behind the driver seat, as someone already mentioned. But the AC condenser fans are right in front of each front wheel.

 

[Computron]

The significant clicking that I hear is from the fuel-pump relay behind the driver seat, as someone already mentioned. But the AC condenser fans are right in front of each front wheel.

Does this fuel pump relay click happen in idle when the car is warming up or just at high engine speed? Mine is happening at idle when I warm up the car in the morning.

 

[jwmelvin]

Does this fuel pump relay click happen in idle when the car is warming up or just at high engine speed? Mine is happening at idle when I warm up the car in the morning.

I don't remember mine doing it at idle. I will try to pay more attention. My car has a CTSC, which means the fuel-pump resistor should be bypassed, but I do still hear the relay.

 

[Computron]

So just an update on this... I have been trying to home in on where this relay clicking sound is coming from and it's definitely not in the front of the car, so I don't think it's any of the fans. It's coming from the engine compartment more on the passenger side than the drive side. It's very easy to make it happen. I just start the car and let it sit there and idle for a few minutes. Definitely NOT long enough for the coolant to heat up to the point that the fan comes on and my A/C is off, so it's not that either.

Furthermore, when I do hear the click, I checked the front and the fans are not on...

But when I hear the click, I also see and hear a change in the engine speed like there is an extra load on the engine, but then after about 30 secs or so it clicks again and returns to normal. Then a few minutes later it does it again. The behavior is almost exactly like the A/C compressor going on and off, but I know for certain that is NOT what is happening.

Are there any other primers out there that have seen or experienced this? Mine is an 2004 if that matters. It's so obvious and unusual that hopefully some of you others out there have experienced it. I just want to make sure this is normal and not something wrong with my car. Of course, it would be great to know exactly what is going on too!

 

[docjohn]

you have a low emissions re-circulation air system on your car that older cars don't have.

 

[Computron]

you have a low emissions re-circulation air system on your car that older cars don't have.

Thanks for that comment. Does that cause a click? What is it doing? Do you know the exact part or component that makes the noise?

 

[shawn110975]

its normal for a 2004 to do this like Doc said the pump is located inside the passengerside rear quarter panel, the tubes lead from there inside the engine bay

 

[Computron]

its normal for a 2004 to do this like Doc said the pump is located inside the passengerside rear quarter panel, the tubes lead from there inside the engine bay

Is this only on 2004+, or did the 2002-2003 have it as well?

 

[shawn110975]

I think it started in 2000 air injection to dilute the 02 exiting the mufflers to pass CA smog laws, its still the same pollution but since they add more air it then diluted and the CA smog sniffers think its low emmisions LOL

- - - Updated - - -

at times when the device clicks on the dash lights dim a little if you watch closely I use to hate it

 

[alum04org]

Computron - Have a 2004 and a 2005, and both do this exact same thing. It is normal :smile:

I was always under the belief it was the fuel pump (relay) kicking more premium motion-lotion into my mill(s). Exact signs/sounds you have described.

Not to worry!

 

[Computron]

I think it started in 2000 air injection to dilute the 02 exiting the mufflers to pass CA smog laws, its still the same pollution but since they add more air it then diluted and the CA smog sniffers think its low emmisions LOL

- - - Updated - - -

at times when the device clicks on the dash lights dim a little if you watch closely I use to hate it

Exactly, my dash dims a little and it's like the engine is under more load. I hate it. None of my other Hondas or Acuras do this... that's why I thought it was abnormal. I guess it's a relief that it is normal. Thanks for all the help you guys! Prime is so awesome!