Car won't start when left outside in direct sun

[Chris Yewdall]

Hi
I managed to successfully clean, regrease and rebuild the ignition switch earlier this week based on Drew's guidelines (thanks Drew). The car started up straight away however it has done a couple of strange things since then
While driving up a hill the day after I fixed the switch, the engine just cut out. My wife coasted to the side of the road and the car started up straight away.
When she left it out in the sun after driving it a couple of days ago, it wouldn't start. This has happened before and I had attributed it to the bad ignition switch issue. Leave it to cool and it will start fine.
Has anyone seen this behavior where the car temporarily won't start if it is left outside in the sun after being driven?
Thanks
Chris

 

[CDX_NSX]

When it doesn't start, does it crank? Does it appear like it isn't getting any fuel?

If so, it's probably your main relay that is bad.

 

[Chris Yewdall]

Yes, the car cranks and yes, I had thought that I might need to replace the fuel filter since it has the symptoms of fuel starvation. My guess was that there was some sort of heat induced 'air lock' happening.
Chris

 

[Shumdit]

Try the main relay as suggested. If the car has 50K miles or is more than 5 or 6 years old this can go bad, and the hot conditions you mention are the exact symptoms. Feel good, it's an easy, cheap repair!

 

[Chris Yewdall]

Re: Main Relay location

I did a quick search on the site for Main Relay and only came up with 9 references. I assume the unit is located near the ECU behind the passenger seat trim panel?
I'll have a look this weekend and perhaps try to resolder some of the joints if they're fractured since the car is a 91 with 90K miles.
Chris

 

[Chris Yewdall]

Re: Ignore the last post

OK, so I searched the SITE instead of the FORUMS. Found that the main relay is in the engine bay on the passenger side with fins on it!
Chris

 

[CDX_NSX]

Re: Main Relay location

Yes, it's located near the ECU, but higher up and closer to the middle. You only have to remove the top trim panel to access it.

 

[Larry Bastanza]

Re: Ignore the last post

OK, so I searched the SITE instead of the FORUMS. Found that the main relay is in the engine bay on the passenger side with fins on it!
Chris

No, it is located behind the passenger seat just to the left (from the drivers position) of the ECU. You will need to remove the upper interior rear panel to get to it, and easier if you also remove the panel behind the passenger seat.

The device you are describing is the fuel pump resistor.

HTH,
LarryB

 

[CDX_NSX]

Re: Ignore the last post

Yeah, what Larry said. My "yes" was to your assumption that it was behind the passenger seat near the ECU.

 

[Jin1976]

Went to my mechanic today. The symptom you describe also happen to my car. I thought it was the main relay. My mechanics said my main relay is okay since when I switch on the car he hear two tick (second one comes 2 second after the first tick). He describe the first tick is ecu is switched on thru the main relay and the second one is the fuel pump current gone thru the relay. So my main relay is okay for a 15 year old car. The real culprit was the fuel pump resistor. He follow the steps given in the NSX repair manual. BTW he is also a Ferrari mechanics so I won't argue with his comment about my car. I will get the resistor tomorrow. Just hope its still in stock and not very expensive. Last repair was the O2 sensors and boy they are expensive.

Take your car to somebody who really knows about NSX and see what to be replace.

 

[NSX 3.0]

http://daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=1636