Another car won't start riddle...

[Owali]

I read a lot of threads and checked the usual things, but I am still stumped. So here it goes... The car has been driving fine, with no starting problems. Last night I parked it for 5 minutes and when I tried to start...nothing. No cranking, turning or clicking. The headlights, radio, A/C, and dash lights were working, and the voltage gauge gave me a good reading, but no noise. I wiggled the keys but nothing flickered or changed. What makes it really strange is that my brake pedal would not go down very far, only like 1/4 inch, it didnt do that five minutes ago, but I am not sure if it is related.

I started looking for bad connections or a blown fuse. The battery terminal was tight and clean. I could not find any loose grounds. So I figured it was my ignition switch. I took it out, and accidently broke the plastic in the process. So I will have to wait for a new one to come in before testing that. In the meantime I checked the starter by applying 12V to the solenoid terminal. The engine would turn over, so I dont think the starter is going bad.

I know I need a new ignition switch, but something tells me that was not the original problem, because my lights were not flickering. I am going to check my main relay, but those symptoms dont really sound like mine. I am not sure what else could be the problem, and I am not sure what my brake pedal has to do with it.

Any suggestions?

 

[EdinKali]

Check the clutch pedal switch. Car won't turn over if that switch isn't engaged.

 

[pgilliam1]

You're going in the right direction. Battery connections, ignition switch, main relay (resolder the joints if you haven't - you can't see the cracks without a good magnifier) and starter. Is there a switch on the clutch pedal that if not depressed won't allow starting ?

 

[Owali]

I checked all the connections I could think of and I tried to check the clutch switch. I can't see the black peg on the back of it to see if it is moving or not. Is there any other way to check its function besides doing a continuity check? I may just order a new one while I am getting the new ignition switch.

Is my brake pedal pressure that I mentioned earlier related to any of this?

Thanks

 

[EdinKali]

Best way is a continuity check. If you don't have an ohm meter you can get one cheap at a local electronics store($10-$20) or a continuity tester from an auto part store for less than $10 iirc.

When the engine is off(no vacuum for the power brake assist) your brake pedal will feel stiffer than usual.

 

[ftuhy]

These observations are all from the 1995-1996 Electrical Troubleshooting Manual. You should check the ETM for your year.

The ignition switch turns on the power, and a "Starter Cut Relay" sends that power to the starter if the cluth pedal is depressed and the Security Control Unit is happy. See page 21 and 21-1 of the '95 ETM.

I believe you connected the black/white lead of the starter to 12V and the starter cranked. Correct? If so, that means the problem is in one or more of the following: the clutch pedal switch, the starter cut relay, the security control unit, or ground to the security control unit. It also means your battery, the battery cables, the cable to the starter, and the starter ground are OK.

The clutch pedal switch contacts close if the pedal is fully depressed. To test that switch, short between the two pins of that connector & see if the car will start. Do NOT short either pin to ground. (Or, disconnect the cable to the clutch pedal switch, put an Ohmmeter across the switch contacts and it should read open circuit with the clutch released, and near zero Ohms with the clutch pedal pressed to the floor.)

To check if the problem is the power cut relay or the security system, short between pins 1 & 3 of the power cut relay, then turn the ignition switch to start. If that works, either the relay is bad or the security systems is malfunctioning or an input to the security system is making it think you are trying to steal the car.

In any case, you most likely will need to look at the ETM to follow the circuit and locate the components. I'm an electrical engineer, so schematics are easy for me to follow. However, I can appreciate that many people are not similarly afflicted.

If you are not comfortable around electrical circuits, and the starter switch is not the problem, it may be time to seek help.

 

[Doc308]

I had this exact, intermittent problem with my '92. In my case it was the clutch no-start swtich. Since disconnecting and short-circuiting the switch, as described above, it never happened again. Another thing to check though is the wire which attaches to the starter solenoid. That connector was also loose my car, but it turned out to not be the problem.

 

[joe]

My 92 had a bad ign sw. The contacts get hot,Take it apart look at it. Use an ohm meter,its all in the service manual.. I was 150 miles from home and after cleaning it up it worked until I replaced it. good luck.

 

[Owali]

Great suggestions, thanks. I will give it a try. Does anyone know the part number for the starter cut relay, I could not find it on the dealer website?

 

[Larry Bastanza]

It is either #15 or #16 on this slide:

http://www.acuraautomotiveparts.org...omp=List All&vinnoT=&trim=&trans=&view=normal

HTH,
LarryB

 

[MiamiMermaid]

Check the clutch pedal switch. Car won't turn over if that switch isn't engaged.

Yup! this JUST happened to me on Wednesday.... Tried checking everything: battery, main relay, connections to solenoid starter.... scratching head, then saw some small plastic pieces in the footwell. Apparently, when it gets hot out, it can melt and cause the pin (or namely, switch') to crack. An easy fix... Hoping this is your case*

Edit: If this is the case, the part # is 46505-SA5-000
Here's a good thread on this w/ pics if you are having difficulty locating the clutch switch : http://www.nsxprime.com/forums/showthread.php?t=124118&highlight=part+clutch+pin

 

[OLDMNSX]

Check to see if a piece of the broken switch from the clutch pedal has gotten into the brake master cylinder plunger mechanism. That is about the only way the two could be related.

 

[Kelly's NSX]

any updates omar? if i can help let me know. im free this weekend

 

[d.n]

Just bumping this up in case anybody else needs the part # in the future for the starter cut relay. When I pulled mine out the part # on the relay matched #16 in Larry's link:

39797-SE3-003 RELAY ASSY., POWER (4P) (056700-85700) (DENSO)

According to the manual the test procedure for this relay is to apply power to two pins and the other two should connect (diagram in the service manual). The other two are open otherwise. My relay would click so I assumed it was good. After pulling it and testing it the two pins would stay open even after the click.

It is either #15 or #16 on this slide:

http://www.acuraautomotiveparts.org/acura/jsp/mws/prddisplay.jsp?inputstate=5&catcgry1=NSX&catcgry2=1992&catcgry3=2DR+NSX&catcgry4=KA5MT&catcgry5=CONTROL+UNIT+(2)&ListAll=All&vinsrch=no&systemcomp=List%20All&vinnoT=&trim=&trans=&view=normal

HTH,
LarryB