Please help with diagnosing problem

[ilya]

I've started having an issue with my NSX the last couple days. Before I take it to the shop I would love to get some possibilities on what it may be. I think the collective knowledge on this board is more than any one person could have.

Yesterday evening, I started the car in my garage. I usually idle for a minute or two before taking off. After about 30 seconds, the car just shut off. I fiugred no big deal, sometimes it happens... idle drops a bit low and car shuts off. Turned it on again and it started without hesitation. Drove around the block to the gas station and am waiting to fill up... car shuts off again. I fill up and drive up the street to where I was going. By now, I'm thinking it's some idle problem while I'm stationary.

This morning, I start the car again. After about 30 seconds, it ALMOST dies, but the computer catches it and swings the needle up to keep it from shutting off. So now I know it's definitely a problem I need to have checked.

The kicker comes next. Five minutes later, I am driving toward the freeway. At this point, I am thinking I have an idle problem.
I am driving about 30mph in second gear at about 3000RPMS cruising. The car JUST SHUTS OFF and I am coasting at 30MPH. I put it in neutral as I am moving, start the car (starts again without any problem), stick it back in second and am on my way again. No more problems all the way to work.

Sounds like something is going out or having trouble, but I habe no idea of what it may be. It can't be my idle since it shut straight off at 3000RPM at 30MPH while in gear and accelerating (mildly). Could it be fuel delivery? Any ideas or help would be greatly appreciated. I'm hoping this is semi-common and won't take 5 trips to a shop to fix (like my last problem... ended up being a bad half-shaft).

Additional info: There is no check engine light. When the car shuts off, it comes on as usual with a couple other lights (as if keys are in ignition). While the car is running, the idle is perfect. It stays steady at all times between 500-750.

Thanks again in advance.

 

[MAJOR STONER]

Fuel pump?

 

[hgunnerz]

Fuel pump maybe. seems like an injector or spark plug would just run rough, as there are 5 others to catch it.

I would suggest electrical checkup, loose connection maybe? Also some engine sensors (ie: MAP or timing) failing could cause that symptom?

some others on the board (M.B.???) may have a lot better ideas of where to look.

hg

 

[dummy]

From you description it sounds like an intermittent electrical problem. First thing to check is any area where work was recently performed. Probably not much help, but I had similar symptoms on a car with a distributor where the resistance of the wire to the coil would change significantly with temperature causing the cessation of spark in the distributor. Took me over 6 months to figure it out due to the intermittency of the failure. Fix was to install a fixed value resistor in the circuit. The electrical system of the NSX is different, but it may offer some insight as to what type of problem you have.

 

[true]

My first guess would be the ignitor. Honda is famous for having skanky ignitors...those are the symptoms. If the fuel pump is failing you can turn your car to accessory and just listen. If there is a problem, it will probably sound a bit strange. I would go with ignition issue over fuel delivery. Generally you can hear a bad fuel pump...and in the case the fuel pump stops..there is probably enough pressure for the car to stumble to its death. If its running perfect and shuts off on a dime its more likely then not some aspect of electronics.

------------------
jack of all trades, master of some.

 

[ilya]

I finally spoke to NSX Modified and he suspects the problem is similar to what you just described. He thinks it's something called the ignition pigtail (that's what it sounded like) and needs to be replaced, cheap part. Something to do with a spring and ignition. He must have come across this problem before as he came up with it pretty quickly. I'll post if that was the case upon my return.

 

[burbel]

Yeah, I was going to say something with the ignition (not the igniter unit). I had my igniter go out, for around 9months cylinder #1 wasn't firing... Duh...

But if there was a problem with your ignition switch, this could cause what you're seeing, I think, and these do go bad.

 

[steveny]

A friend of mine had the exact same problem with his vehicle. He had almost everything in the fuel and electrical system replaced. The mechanic was completely puzzled. My friend had spent tons of money trying to fix the car. Come to find out there was a movie ticket in the gas tank that would occasionally float over the fuel pick up and get sucked on to it thus shutting off the fuel. Probably not your problem but I love telling this story.

 

[BoneZ]

Burbel :

In regards to your 1st cylinder not firing for 9 months.

What were the symptons, and how was it tested to confirm failure?

Just kind of curious...

-B

 

[ilya]

For anyone interested, the problem was resolved last night. A bad fuel relay box was causing the problem. This was a black box to the right of the ECU.
Strange how it was an electrical issue and no trouble codes were tripped and I had no check lights. Bad news is that box isn't too cheap I am told. I'll be calling Gold Coast today to see the cost.

Thanks for the help guys.