Another Main Relay Thread!

[Lude_2_NSX]

After years of owning multiple late 80's and early 90's Hondas, i'm no stranger to the main relay problems. My 91 just rolled over 109K miles a couple of weekends ago. The main relay is original, but I have been holding off on repairing/replacing it until I actually needed to. Sure enough, a hot summer day yesterday I was driving and the car cut off. I knew immediately what it was. It started right back up without even dropping a gear, so I drove it home and turned it off in my garage. Went to restart, and I couldn't hear the fuel pump prime, and I knew it was done for. Ill be soldering the original this evening, already have a spare new relay on order. I plan to keep one in the glovebox for the future.

All I have to say, is that I love this car. It has never left me stranded, this is the closest it's ever been to "breaking down" on me, and she literally waits until she is in the garage after a quick little warning that day. So thoughtful.

I'll keep you guys posted if the main relay doesn't do the trick. Otherwise, I'm looking forward to finally getting this little thorn of a fix done.

 

[anesthesia]

Last year I replaced both just for preventive measures, ignition switch

 

[BATMANs]

Last year I replaced both just for preventive measures, ignition switch

This.

 

[nigel]

I keep a new, still in the Honda package, relay the glove box just in case.

Cheers
nigel

 

[Lude_2_NSX]

Last year I replaced both just for preventive measures, ignition switch

Hmm, I've read about this as well. Maybe it hasn't stuck with me as much as the relay, because I've never had issues with it before. I'll look a bit more into this as well, to continue the reliability streak that this car deserves.

 

[BATMANs]

Hmm, I've read about this as well. Maybe it hasn't stuck with me as much as the relay, because I've never had issues with it before. I'll look a bit more into this as well, to continue the reliability streak that this car deserves.

When both started to fail on me they did give me some ample warning.

U just have to be keen on what the symptoms are.

If I didn't know I would have thought they were like a bad plug wire or plugs.

 

[Lude_2_NSX]

When both started to fail on me they did give me some ample warning.

U just have to be keen on what the symptoms are.

If I didn't know I would have thought they were like a bad plug wire or plugs.

I'll put it next on the list! Looks like i can get a 35130-SL0-003 (Originally 35130-SL0-A01) from Delray Acura for $55. Too cheap not to replace as a preventative measure. Thanks NSX community!

 

[BATMANs]

I'll put it next on the list! Looks like i can get a 35130-SL0-003 (Originally 35130-SL0-A01) from Delray Acura for $55. Too cheap not to replace as a preventative measure. Thanks NSX community!

I had Fremont Acura do that for me and then had Best Buy (when they did custom work) do this: https://www.scienceofspeed.com/inde...nceofspeed-s2000-push-button-kit-for-nsx.html

Really made the NSX 1.0 feel more modern - along with my Pioneer infotainment double DIN.

 

[Lude_2_NSX]

I had Fremont Acura do that for me and then had Best Buy (when they did custom work) do this: https://www.scienceofspeed.com/inde...nceofspeed-s2000-push-button-kit-for-nsx.html

Really made the NSX 1.0 feel more modern - along with my Pioneer infotainment double DIN.

Ignition switch and main relay ordered. Can't believe I didn't do this sooner. $150 piece of mind.

 

[Old Guy]

Save the old ignition switch. If you go back 4 - 5 years I recall a thread on cleaning up an older ignition switch to fix non operation. In 10 plus years, like an increasing number of NSX parts replacement switches may be difficult to find and a rehabilitated switch may have value.

Since the main relay is used across other Honda models, its more common and unlikely to have future value. However, as you plan to do reflowing the solder joints can give you a back-up which may come in handy in say 2018 - 1991 = 27 years from now. I wouldn't bother putting it in the glove box since its unlikely that you are going to be needing it soon - some place wrapped up in the trunk.

On a serious and more ugly note. You might want to think about the fuel pump if it is still original. When fuel pumps fail due to commutator wear, they don't give much in the way of advance notice. On EFI cars that have an external mount fuel pump, I have had luck in getting a geriatric fuel pump to start up by rapping the fuel pump holder. This will sometimes jar the rotor enough to move off of a bad commutator segment allowing the pump to start up. However, with an in-tank pump, rapping the fuel pump on the NSX is not an option. Replacement is kind of ugly so I don't know whether I would replace it or just have a spare on hand.

 

[BB]

In the last 5 years I've had too many electronic module failures on my 91.....

Main relay
Ignition control module
Ignition switch
Climate control module
Radiator fan control unit (37735-PR7-A01)
Turn signal control module (35285-SL0-A01)

In most cases the problem appeared to be leaky capacitors or cracked solder joints. Prior to this I had never experienced any problems with the car. It seems like everything was designed to last for a minimum of about 20 years.

 

[Lude_2_NSX]

Save the old ignition switch. If you go back 4 - 5 years I recall a thread on cleaning up an older ignition switch to fix non operation. In 10 plus years, like an increasing number of NSX parts replacement switches may be difficult to find and a rehabilitated switch may have value.

Since the main relay is used across other Honda models, its more common and unlikely to have future value. However, as you plan to do reflowing the solder joints can give you a back-up which may come in handy in say 2018 - 1991 = 27 years from now. I wouldn't bother putting it in the glove box since its unlikely that you are going to be needing it soon - some place wrapped up in the trunk.

On a serious and more ugly note. You might want to think about the fuel pump if it is still original. When fuel pumps fail due to commutator wear, they don't give much in the way of advance notice. On EFI cars that have an external mount fuel pump, I have had luck in getting a geriatric fuel pump to start up by rapping the fuel pump holder. This will sometimes jar the rotor enough to move off of a bad commutator segment allowing the pump to start up. However, with an in-tank pump, rapping the fuel pump on the NSX is not an option. Replacement is kind of ugly so I don't know whether I would replace it or just have a spare on hand.

I have read about cleaning the ignition switch. I will be doing this (mine probable doesn't need it) once I remove it to install the new one, and saving the original with all of my other spare NSX parts. I re-flowed the main relay yesterday, it was OBVIOUS that there was a connection at one of the through-hole joints. Car fired up no problem afterwards. Once the new main relay comes, i'll be tossing this one in the glove box as a "known-good" spare.

In regards to the fuel pump, I replaced it with this less than 10K miles ago:

https://www.scienceofspeed.com/inde...-high-pressure-fuel-pump-nsx-fitting-kit.html

Also installed a fuel pressure gauge, new fuel filter, and had the injectors ultrasonically cleaned/balanced around the same time. But to your point, replacement is a bit ugly, but it wasn't as bad as I thought. I mentioned a couple of tricks that helped me here:

http://www.nsxprime.com/forum/showt...nd-Resolution?highlight=fuel+pump+replacement

 

[Ric]

For a 2000 Model with 42k miles, should I replace the ignition switch/main relay for peace of mind? In fact, should I replace anything for peace of mind? Already replaced the timing belt.

 

[Old Guy]

I have a 2000 with around 72,000 miles (its a US market car) and I have not replaced anything on the car other than the scheduled items (TB ....), wear items (brake pads ....) and the window regulator upgrade. At 42,000 miles your car is a low use vehicle. I would not bother with any of those items unless you like spending money. If you want a little insurance, buy a main FI relay and keep it as a spare. If you pay attention, the ignition switch will give you some advance warning with erratic operation before it completely packs it in.

At the rate you use your car and assuming that this is normal driving your probably good for 10+ years.

 

[goldNSX]

For a 2000 Model with 42k miles, should I replace the ignition switch/main relay for peace of mind? In fact, should I replace anything for peace of mind? Already replaced the timing belt.

No. The main relay correlates to mileage but the ignition switch to how many times you've started the car. Unless these miles are very, very short the ignition switch will not be due to replace as a preventative maintenance IMHO.