No Start - Stumped

[HappyHonda]

New member here, but longtime reader. Hope you guys can help me with the first problem I have ever had with my NSX.

I've got a '93 stock manual with 77,000 miles. I tried to start the car last week and got near nothing. When trying to start, I get a single click from the dash, hear the fuel pump, and then nothing. The lights don't dim and I hear nothing from the starter. I have searched the forums here extensively and tried many things, but to no avail. With information found searching these forums, here's what I have done so far:

1. Checked the battery. I even tried to jump the car with a portable jumper.
2. Checked the fuses. All in order with no obvious signs of problems.
3. Checked the clutch interlock switch pad with a borescope. It is in good shape and depresses the switch.
4. Removed the ignition switch, inspected, and cleaned with electronics cleaner. Ignition switch had a small amount of carbon buildup, but nothing concerning.
5. Removed the main relay and checked for cracks or damage. Flexed the board, but saw nothing. It appeared to be in good order.
6. Removed the starter and had it tested. It failed the test, but the shop couldn't find the correct code for the starter so tested it with a same make, similar engine. Based on that, I had the starter rebuilt and successfully tested (at a different shop).
7. Checked the ground wire from the battery. It was solid and showed no signs of corrosion.
8. Checked clamp to battery terminals. Negative clamp was loose, so installed a lead shim.
9. Checked fuel. I've got plenty of fuel and after so many failed start fails, I can smell fuel.
10. Checked alarm functionality. Both the factory alarm arms and disarms with the key and the aftermarket alarm arms and disarms properly with the remote. Not sure if this is sufficient to determine if a problem exists.
11. Shorted the starter trigger and the car started up immediately and car ran without issue. Idle was good and it did not cut out or show any signs of faltering.

Clearly I have I missed something, but what? What else can I do to figure out the source of the problem? Thank you in advance!

 

[cosplayerkyo]

I just went through the same headache. The clutch relay wasn't receiving a proper ground.

My friend was able to track it down to the security unit control module 39880-SL0-A03 (or A04).

Turns out this unit is part of the process of telling your clutch it's being pressed down.

 

[HappyHonda]

Where is it located?

I just went through the same headache. The clutch relay wasn't receiving a proper ground.

My friend was able to track it down to the security unit control module 39880-SL0-A03 (or A04).

Turns out this unit is part of the process of telling your clutch it's being pressed down.

Cosplayerkyo - Thanks for the response. Do you know where the security control module is?

Update: I shorted the clutch interlock switch, but it didn't solve the problem.

 

[Old Guy]

The security control unit is located behind the glove box. Refer to the attached drawing for the location. Shorting across the clutch interlock switch will tell you whether the interlock switch has failed, it will do nothing if the security control unit has failed (refer to the attached wiring diagram). You can do a quick test by jumpering the black white and black blue wires on the starter cut relay together. This completely bypasses the clutch interlock, starter cut relay and the security control unit. If any of these items are the source of your problem, then you should be able to start the car with the jumper in place. If the car doesn't start, then the problem is elsewhere. Get a copy of the on-line service manual to get the individual test procedure for the cut relay and the control unit.

The wiring diagram and the color codes are for a 1991 model year. I do not know whether they apply to the 1993 model year.


If the jumper allows you to start the car, I recommend against treating it as a fix since you have by passed the safety interlock and the anti theft feature.

 

[HappyHonda]

Security Control Unit

The security control unit is located behind the glove box. Refer to the attached drawing for the location. Shorting across the clutch interlock switch will tell you whether the interlock switch has failed, it will do nothing if the security control unit has failed (refer to the attached wiring diagram). You can do a quick test by jumpering the black white and black blue wires on the starter cut relay together. This completely bypasses the clutch interlock, starter cut relay and the security control unit. If any of these items are the source of your problem, then you should be able to start the car with the jumper in place. If the car doesn't start, then the problem is elsewhere. Get a copy of the on-line service manual to get the individual test procedure for the cut relay and the control unit.

The wiring diagram and the color codes are for a 1991 model year. I do not know whether they apply to the 1993 model year.


If the jumper allows you to start the car, I recommend against treating it as a fix since you have by passed the safety interlock and the anti theft feature.

Thanks Old Guy, I'll check it out this week. Hopefully it is easy to get to without doing a large teardown ('93 added the air bag and shrunk the glove box). I'll post back with results. For sure, if it is the problem, I wouldn't bypass it permanently.

 

[silver2002]

Couple questions:

[from above]
1. Checked the battery. I even tried to jump the car with a portable jumper.

Did you jump it at the battery or from the fuse box [and ground on engine block] in the engine bay?

[from above]
8. Checked clamp to battery terminals. Negative clamp was loose, so installed a lead shim

How are your connections at the battery?

I ask because I have seen a car with a fully charged battery be able to operate everything [lights/horn/etc] except the starter because it could not move enough current across dirty/corroded battery posts/connections. Corrosion may not be visible.

 

[HappyHonda]

Couple questions:

[from above]
1. Checked the battery. I even tried to jump the car with a portable jumper.

Did you jump it at the battery or from the fuse box [and ground on engine block] in the engine bay?

[from above]
8. Checked clamp to battery terminals. Negative clamp was loose, so installed a lead shim

How are your connections at the battery?

I ask because I have seen a car with a fully charged battery be able to operate everything [lights/horn/etc] except the starter because it could not move enough current across dirty/corroded battery posts/connections. Corrosion may not be visible.

Silver 2002 - I jumped the car from the fuse box with ground on the engine. I have also shorted the system by putting voltage to the solenoid trigger directly and the car started up fine. From that, I assume that the car is well grounded to the starter.

Regarding the battery posts, upon initial inspection, I noted not even a small amount of corrosion, but cleaned it anyway and have reseated both negative and positive sides multiple times. I have checked the ground wire from the battery to the chassis and it was well connected and also without any issue of corrosion. Using a meter, I have checked the voltage drop across the battery terminal post and wire/connections (both positive and negative). All is well there.

 

[VancouverBCnsx]

I recently experienced the what seems to be the same no start problem on my 91 NSX. A single click was the only sound heard when attempting to start the engine although if I persisted with multiple retrys it often would eventually restart. In the end, it proved to be the starter motor.
Does the instrument panel light up normally in the second key position? If not this could be indicative of a faulty ignition switch.
Good luck.

 

[HappyHonda]

VancouverBCnsx - Although it seems that I have the same symptoms as you, I've eliminated the starter because I have had it rebuilt. Additionally, after the rebuild, I shorted the starter by putting 12V on the solenoid trigger. With the short, the car started right up. I pulled the ignition switch as well and cleaned and inspected it.

 

[robbiedawg]

i also had this starting problem,it would click when i turned the key but not start,and it also turned out to be a bad starter.the oem one,made by denso,was over $900,so i went with this denso reman starter for about $200.-

http://shop.advanceautoparts.com/p/...-280-0197/20840145-P?searchTerm=denso+starter

i don't want to put cheap crap on my nsx,so i looked into this,and it appeared that it was as good as a new one,and of course redone by the oem company.it has worked fine for a couple of years.

 

[HappyHonda]

robbiedawg - Wish it was the starter, but it works fine as I can tell (just rebuilt and tested).

 

[silver2002]

VancouverBCnsx - Although it seems that I have the same symptoms as you, I've eliminated the starter because I have had it rebuilt. Additionally, after the rebuild, I shorted the starter by putting 12V on the solenoid trigger. With the short, the car started right up. I pulled the ignition switch as well and cleaned and inspected it.

Is the solenoid getting power? [from ignition, to trigger the solenoid] - the solenoid may be bad.
You said click was in dash, solenoid click would be from starter area.
Did you jump on starter side of solenoid or battery side?
Old school is to whack/tap solenoid with a hammer and see if that makes it work [but it rarely does].

 

[nikey22]

check your MAIN RELAY... just b/c you re-soldered it, doesn't mean its necessarily okay. Still could fail. Swap it out with one of your friends? cheap test...

 

[chudson1549]

This^^^^. And check the ignitor

 

[HappyHonda]

Silver2002 - The solenoid trigger is not getting power from the ignition. When shorted directly from the battery to the trigger on the solenoid, the car starts up quick. The starter and solenoid setup was tested when it was rebuilt last week. Since I can start the car with the short to the solenoid trigger in a similar manner that the ignition would apply power, the solenoid and starter are presumed not to be the problem.

- - - Updated - - -

nikey22 - I have ordered a main relay this week considering all the posts I have read about the problems with the main relay. I would have gotten it locally, but local dealer wants $200 for it and it is special order.

- - - Updated - - -

chudson1549 - I am trying to figure out how the ignition and ignition switch can be tested as a complete assembly. With the connectors sealed, it is difficult to get a probe in to test voltage in different key positions. I may have to test continuity with the ignition switch off the ignition once I figure out how it works. I've got my work cut out for me this weekend!

 

[ftuhy]

There are a number of posts on how to disassemble and clean the ignition switch. Been there, done that! Its also relatively inexpensive to replace.

Do you have a multimeter? If so, PM me and I'll walk you through how to check the ignition switch. But fitting under the dash to do that may be more of a headache than a disassemble and clean.

 

[VancouverBCnsx]

HappyHonda

Have you resolved the start issue and can you share the source of the problem?

 

[Larry Bastanza]

I would have to say this does sound like the ignition switch. Not an expensive or labor intensive repair. It is not the Main Relay, which has nothing to do with the starter.

My $.02
LarryB