Symptoms of a master relay failure

[L696ULO]

Hi All

I've been using the car daily recently and went to start it this morning, I turned the key in the ignition all the lights came on but before the engine cranked the displays completely disappeared. The battery it relatively new and the main relay was replaced 3-4 years ago as preventative measure (I still have the 19 year old one).
Is this a symptom of a dead relay or is there a master fuse which is situated between the battery and the rest of the electrics which I can check, if so where is it?

Cheers Rich

[Mistercorn]

You say the battery is relatively new, but I would check the battery voltage whilst this is happening as the first test.

MC

[L696ULO]

Thanks MC

The problem is there aren't any display lights coming on at all, it's as if there's no battery unless that has completely failed which I can't see happening

[Hagasan]

The leads are still correctly attached to the battery.. New battery, loose terminals, daily driving... Might have started to detach?

[Kaz-kzukNA1]

Even with the dead Main Relay, you can still crank the engine. The starter circuit requires huge current so it’s separated from the rest of the system.

It sounds like battery or IG key contacts.

What was the voltage reading when all the lights came on with IG key in P2/ON position?
You should see at least 12V when IG key is in P2/ON position.

Even with 12V on the gauge while in P2, this doesn’t mean your battery is perfect as internal resistance will hide the real performance. You need to have it drop/load tested.
As a quick test, while in P2, try switching On the headlights and the rear defogger and monitor the voltage gauge.
If it drops quickly within 1 - 2min, check your battery and battery positive and GND cable.

If it's IG key contact, it can be cleaned but normally, you should be able to at least crank the engine and then the engine will stop as soon as you release the key.
Some of the security system will prevent you from cranking the engine and even disable all the lights in the dash depending on how it was wired but not that common especially if it was installed by the Honda dealers.

[Just read your post #3. Are you saying that now you can no longer see any lights even in P2???]

Kaz

[L696ULO]

Hagasan

The battery has probably been in the car for 18 months to 2 years but I will check all the connections. I had discounted that being the case because the dashbord lights were on initally before disappearing.

Kaz

That's correct - there are no lights at all, as if the battery was completely disconnected

[Kaz-kzukNA1]

Then, as you mentioned, please check the battery connection first.
There are separated fuses used for the group of dash gauges so if none of them are lighting up, it’s further upstream.
50A fuse inside the pentagonal main relay box under the bonnet or further up, it's only the battery connection itself.
No reverse polarity or short circuit, please.

Kaz

[L696ULO]

I've checked the battery connections and when I reconnected the negative terminal it restored the dash lights the volt gauge read 12v then when I tried to start all lights disappeared again and only reappear when I disconnect and reconnect the negative terminal.
The Honda battery was changed April 2013 it looks like it's pointing to a new battery? Any suggestions where I can pick up one without having to wait for Honda to get one? The previous Honda battery lasted 3 years and when replaced I was told it only has a 2 year guarantee

[Mistercorn]

Bosch S4 or S5 from ECP or similar. You get a 4 or 5 year warranty and most likely cheaper as well.

MC

[Kaz-kzukNA1]

Hi, Rich.
I remembered I had the same discussion on here regarding the Honda battery warranty so did some searching and interesting enough, it was with you.

http://www.nsxcb.co.uk/showthread.php?11059-Starting-problem-help

Seems like you are killing the battery every few years.
While you can try installing different battery this time, it may just hide the actual cause of the battery failure.
If the battery was never let to go flat, over charged and looked after properly, it should last for many years.
Many NSX owners are using the battery of more than 5 years old and I know some of them managed to survive with the same battery for more than 10 years.

Do you have aftermarket security system apart from the one installed by Honda garage that is actually from Hamilton & Palmer?

What kind of battery conditioner are you using?

Does your security system try to close all door windows once you arm it? I know some of the aftermarket ones can be wired like that and window regulator motor can draw well over 10A EACH.


By the way, I think it’s worth checking with another Honda garage for the battery warranty information because unless something changed, as mentioned in my previous post in the above link, I still think it’s for 3 years…..
They can test the battery for you at the same time as they need to fill in the warranty form.
That's how I got the replacement when one battery failed for another owner while I was servicing his NSX.

Kaz

[britlude]

I've checked the battery connections and when I reconnected the negative terminal it restored the dash lights the volt gauge read 12v then when I tried to start all lights disappeared again and only reappear when I disconnect and reconnect the negative terminal.
The Honda battery was changed April 2013 it looks like it's pointing to a new battery? Any suggestions where I can pick up one without having to wait for Honda to get one? The previous Honda battery lasted 3 years and when replaced I was told it only has a 2 year guarantee


sounds like a dodgy connection that goes open circuit as soon as it's loaded... check the chassis end of the earth lead! or put a jump lead between the neg terminal and a suitable bolt on the chassis, effectively replacing the earth lead....

[L696ULO]

Thanks hagasan, Kaz and MC

A quick call to my local ECP and they aBosch S4 in stock, grabbed it , gave over £59 then home to fit, fired up first time so I just had to take it for a spin!

Thanks again Rich
ps hope this one last longer than the last two Honda ones

[L696ULO]

And thanks Britlude, I'll check that too just in case

[britlude]

what do you expect, i mean, using it as a daily driver....... :)

[L696ULO]

I know these few weeks of daily driving might double my normal annual mileage! maybe it was traumatised :rolleyes:

[L696ULO]

My moment of glee and damning the Honda battery was short-lived.

After my drive post fitting the new Bosch battery I parked the car and locked it overnight without setting the alarm (the immobiliser kicks in after 30 secs) so that I could rule out if there was any drain on the battery via the alarm.

This morning I had exactly the same problem, so out came the spare wheel and brace, disconnected both battery terminals, checked the chassis end of the earth lead as Britlude suggested which was tight but I nipped it up very slightly. Reconnected the same battery and it fired up first time. Now I'm thinking the old battery might of still been good (the 'eye' was showing green which I got it into the light).

Open to any other ideas/notions/suggestions?

Getting a dab hand at the new procedure but I would rather not be doing it ! I'm using it today so I'll see what happens when I need to go home.

cheers Rich

[L696ULO]

I forgot to mention the previous owner had fitted a knurled isolator knob to the negative earth lead (so he could easily disconnect the battery without having to unbolt the terminals).
When I lost all power after trying to start the car I undid the isolator and tightened it up which restored the power to the dash lights etc but as soon as I went to P3 to start the power goes. The only time it cranks and starts is when the battery is completely disconnected and reconnected at the battery terminals.

[britlude]

definitely sounding like a main cable.... if/when it happens again, try removing/refitting just the neg cable, see if that sorts it... if so i'd be inclined to remove the cable completely, inspect/clean both ends, clean where it attaches to the car...

perhaps the isolator is giving up the ghost....

a dirty/bad connection can let enough current flow for the basics, but as soon as a heavy load is needed it goes phut and the connection is broken.....

[L696ULO]

Thanks Jonathan
The latest update is the car sat in the car park for 5 hours and started no problem, drove it, parked it for 2 hours and the problem reappeared. Managed to remove the negative terminal without removing the spare wheel etc put it back on tightened it and it started? I can't understand why using the isolator to break the connection which is the same as removing the terminal merely restores the power but doesn't allow the car to start.
I'll do as you suggest and clean both ends to try and resolve the issue if it continues I'll remove the isolator if that doesn't work put my hands in my pocket and get a new cable.
Thanks again

[britlude]

theres a dodgy connection there somewhere, probably triggered by the heat under the bonnet after a run, but ok once it's all cooled after 5 hours!

when you remove it and reattach you are moving the duff joint enough to restore the connection.... it looks like i'd be checking the cable/isolator connection next!


what type is it? the red key
http://www.bcae1.com/images/jpegs/IMG_5967b.jpg

or the one that fits direct to the battery terminal?
http://www.elise-shop.com/images/large/BattInterupter-LOW_LRG.jpg

[L696ULO]

It's the 2nd one that fits directly to the terminal. Your heat/cooling theory doesn't hold as it did start after being left overnight. I'll start the task tomorrow afternoon and report back.
if any other ideas come to mind please keep posting

thanks Rich

[britlude]

it was only a theory!!! lol

if sorting the earth lead doesn't cure it, then the car is obviously possessed by an evil spirit. for a small fee, i can remove said car and save you a lifetime of earth lead frustration

:)

[Mistercorn]

As I suggested in the first place, I would still be attacking this with a multimeter to find out what is going on. You might need a helper, but check the voltage at different points, directly across the battery, then from the chassis to the battery, then from the chassis to the starter motor. Basically working from one end of the chain to the other to find out where the problem is. I much prefer the methodical approach to speculation and guesswork. It must be the engineer in me trying to get out.
It is certainly a strange problem, sounds almost like some sort of weird immobiliser issue.

MC

[L696ULO]

Update

I gave the earth lead surfaces a good clean as well as the isolator on Friday and so far the NSX is back to normal reliable self. I now have probably a good 2 1/2 year old battery sitting in the garage at least the Bosch one has a 4 year guarantee.
Thanks Kaz, MC and Jonathan

[britlude]

... so you don't want to pay me to take it away then????

... the offer still stands... :)

[L696ULO]

It is a gracious and very kind offer however I think I might keep it for the time. There is still another week or so of being my daily so in the words of Basil Fawty it might get a damn good thrashing if it misbehaves!