NSX completely shut down while driving and would not start

[Ojas]

I'm hoping someone can help me track down a problem I had. I would appreciate any suggestions. Thanks in advance.

Problem: car shut down
A few nights ago, while on my way home, the car completely shuts down: Both engine and electrical. It was like someone disconnected the battery and alternator: Engine was dead and I had no headlights, no hazard lights, no interior lights, no power door locks, no power windows, etc. It was pretty freaky since it quit on a bridge with no shoulder and, without any lights, I was worried that other drivers would not see me in the dark.

A few observations
Fortunately, I had enough speed to pull off past the bridge safely. I checked the battery connection and wiggled it around: It seemed fine. I really did not know what else to check: The electrical boxes under the hood and in the engine bay looked okay.

Even though it did not seem like the main relay could be the culprit (since a defective relay should not cause the engine and all electrical to not work), I removed the rear panel and tapped on the main relay a few times, hoping to fix an open or short... no luck. It seemed unlikely that the ignition switch could be the problem, either.

While waiting for the tow truck, I noticed that some of the electrical components were at least getting some power, even though they did not work: 1) Even though the climate control would not work, I noticed the green LED that indicated fresh air was on. 2) Also, the radio would not work, but I could hear the a little pop-sound when I turned the key, indicating that the amplifier might be getting some power.

Back to normal (for now)
The car has been in my garage since then. Some time yesterday (about 36 hours after it quit), the car returned to normal. Obviously, I do not want to drive the car until I figure out what the problem is. However, since everything seems to be fine now, I'm not sure what to check first. Any ideas?

BTW: Something similiar happened once a few months ago, but it shutdown for only a few seconds. It started right up and when I took it to the shop, they found nothing wrong and suspected something like a loose battery cable, which they re-tightened. Apparently, this did not solve the problem.

 

[rbirling]

Ojas,

Turn your ignition key to 'on', so all the dash lights are on, then wiggle it around. If you can get the ignition to go off, your switch is going bad. I had to replace mine a couple of years ago. Otherwise, I'd guess that main relay everyone talks about. I haven't had to deal with that one yet....

 

[Ojas]

Thanks for the suggestion, Bob.

The dash lights don't even come on. Putting the key in and switching it to any position does absolutely nothing (other than the LED on the climate control and speaker pop, I mentioned before).

That makes me wonder: In addition to causing the car not to start, could a defective ignition switch cut off major electrical components, such as the headlights, door locks, etc.?

 

[D'Ecosse]

That makes me wonder: In addition to causing the car not to start, could a defective ignition switch cut off major electrical components, such as the headlights, door locks, etc.?

No - I think you maybe have a bad battery connection. Don't forget to check the ground as well as the +. It possibly could be a problem with the battery itself. I had one in my DD that suddenly just seemed to short out.

 

[EIFFEL]

I would strongly suggest check the ignitin switch for burnt marks. that's on the back of the switch, (electrical portion). My money is on a defective switch.

 

[loNfastNSX]

Hey Ojas. You may want to check and see if you have one of those batteries that has a quick terminal disconnect for things like winter storage. A fellow NSXer was at my warehouse a few weeks ago and his car was in perfesct working order. After we detailed his car however, he went to start it and NOTHING. Very little power getting to the door lights, barely an ornge glow, was all we could see. It turned out the he had one of these batteries on his car. We turned the green knob on the battery terminal and that fixed it. Hope this helps in some way!

 

[hlweyl]

Sounds a little suspicious of an aftermarket alarm with an electrical gremlin in it. Are you saying the car is completely back to normal now?

 

[MJK]

My money is on a defective switch.

Mine too. A friend with a CL had these EXACT same symtoms and it was the ignition switch.

 

[rbirling]

Oops, missed the part where you said you didn't think it was the ignition switch. I can't imaging that disabling anything that works without the ignition being on. OTOH, a loose battery terminal shouldn't cause the car to die once it's running. My money's on the main relay now.

 

[Ponyboy]

Wow, sorry you went through this Ojas. Sounds scarey.

I have to believe the battery connection is the culprit. I know of no other explanation for every system shutting down while the vehicle is in operation.

 

[docjohn]

Do you have after market headers?I ask because I had a bizare non starting car with some electrical stuff working and others not years ago.The cause was my DC header(old design) that had the O2 bolt sensor wires hitting the firewall.At some point the wires must have shorted or been damaged due to mechanical forces,the result was a car that was similar to what you describe.Of course its a long shot but I thought I'd confuse the situation abit

 

[hlweyl]

If it's a loose battery connection, I would ask why did the car just go dead? The altenator should be powering the car once running.

If it's a main relay, I would again ask why did the car power down, that would only shut off fuel.

 

[donwon]

I had a loose battery connection at one time, and it does shut everything off. I was driving when one of the terminals popped off, even the engine cut off right were I stood.

 

[EIFFEL]

may be we can start a poll on what may be wrong with the car? mine and White94 are betting on ignition switch.

 

[MJK]

Perhaps a pool?

$5 a person w/ half the proceeds going to repair?

 

[dgaetano]

If it's a loose battery connection, I would ask why did the car just go dead? The altenator should be powering the car once running.

I'm going to take a shot at answering this, but be warned, I don't actually know jack about how cars are wired. I may be wrong (and if so somebody please correct me). That said...

The alternator and battery are in series, not parallel. So basically the car is one big closed circuit, battery to alternator to car to battery. When the car is not running the battery provides 12V and current. Once the car starts running the alternator ups the circuit voltage thus forcing the battery to charge. If the battery were to go dead at this point the car would still run fine so long as the battery is at least allowing current to flow through it.

If, on the other hand, the circuit is broken (say you disconnected the battery) then the car will go dead. It makes no difference whether the alternator is on or not, in a broken circuit there's nowhere for the current to go. An accidental ground (a short) would do the same thing, not allowing the current to flow past it.

Although the break (or short) could be anywhere, odds are always good it's one of the big wear items that make/break the circuit connections in the car: the ignition and the main relay.

 

[drew]

Having vivid memories of my main relay going dead: when it does die, the rest of the dash lights stay ON.

In fact, the car otherwise seems quite normal except the engine is off and it just cranks away not starting.

Ojas, I would put my $5 on the ignition switch, or from your POV the ~$150 for the actual part.

I believe the III (Start) spot on the switch does shut down power to everything else, to maximize power to the starter. It might keep power to the stereo to maintain its state.

Drew

/Off topic: I got caught on a couple of computer gigs...but the NSX parts program is alive and well. Just have to mask in/out the part catalog. Thanks for your help...

 

[burbel]

Hey Ojas, sorry to hear about this...

When this happened to my NSX, I had blown one of the fuses/relays on the car. In this case, it was from an improperly routed O2 sensor wire. The wire shorted out, caused the fuse to blow, and completely killed the car.

Just one more thing to check. Guess I'll put my $5 on a relay/fuse.

 

[Larry Bastanza]

Not that I have an answer for this but the ignition switch bad would still allow parking light etc to work correct?? I know for example I can pop my headlights and turn the parking light on without the key even in place.

The negative terminal on the battery is notorious for stretching over time and appearing tight. Really try to force it to twist.

Other then that you need a voltmemter and to start the hunt.

Good Luck. Sorry I have no better advice.

LarryB

 

[ncdogdoc]

........The negative terminal on the battery is notorious for stretching over time and appearing tight. Really try to force it to twist......LarryB

It is the negative or ground wire that causes the problem. Positive can loosen while running. I lost a ground cable coming out of Oak Tree one Sunday at VIR. The car just dies. No emergency lights, no brake lights, and a bunch of really fast Ricky Racers trying to kill me as I struggle to get off the track. It could be loose at the battery or at the body connection.

 

[drew]

Larry

Perhaps the ignition switch can fail in slightly different ways? The switch is rather complex, with many contacts and not all of them have to fail to make the switch bad. I've never experienced this failure with a Honda product, so I'm just guessing here...but, it seems reasonable.

Also I've never tested running the NSX without the battery, but on other cars (Toyota, Ford, Chevy) if you start the car with a battery and immediately remove it: the car will continue to run and operate normally.

I'm holding out for a switch and/or a main fuse.

I think that hot wiring a car is a much more fun way to diagnose this problem

Drew

 

[Ojas]

Since this was a problem I had never heard of before, I thought I would be lucky to get a single response and here I have 20! Thanks everyone for the replies. It's been very helpful.

To answer a few questions:

• hlweyl: I do not have an aftermarket alarm and car is completely normal now.
• docjohn: I do have Comptech headers.

The loose battery connection thing is interesting because according to donwon and ncdogdoc, the car will die if the connection is cut. This is not what I would have expected and is unlike other cars I have owned. I will do a thorough check on all the connections.

burbel: I'm glad you replied and refreshed my memory on the problem you had last year. Even though I think my problem is different (I did not blow any fuses), as both you and docjohn mention: the O2 wire is something I really need to check.

I did spend some time with the service manual, examining the circuits affected by the ignition switch. At this point, I don't think I can exclude the switch as the possible culprit. Since the problem is intermittent, I can't do more than a visual inspection. However, if the problem occurs again, I think I can use the diagram in the manual to determine if the switch is defective (perhaps using drew's hot-wiring method of diagnosis ).

I have a few questions:

• For those who have had the ignition switch fail, was it an intermittent problem? I assume there was a bad connection, were you able to wiggle the key around in the switch to make a temporary good connection?
• White94: On your friend's CL, do you know if the defective switch caused all the components (headlight, interior lights, etc.) to not work?

I have enough to go on right now to get started. I'll keep you posted. In the meantime, if anyone comes across other ideas, please share. Thanks again.

 

[brahtw8]

My recollection of my own main relay failure is that the car died completely, electrical and all (which doesn't seem to make sense given it is the main FUEL relay, but that is what happened). It was an intermittent failure that occurred a few times on the Highway, but never from a cold start, although that has happened to some others.

I would replace the main relay if it hasn't been done.

 

[tomc92bb000059]

I had a corvette and a Supra do the same things you are describing, down to being able to restart later, and in one case the alternator was going bad, and the other the battery was going bad.
my 0.02

 

[rbirling]

Regarding the ignition switch: When mine failed it was intermittent. Also, when it didn't work, I could apply pressure to the right, and the dash lights would come on. When working, applying pressure to the left caused everything to go down.