I have a 1993 NX2000 w/ mods listed in the sig.

Ok. This all started yesterday as a general maintenance/idle fix/gas mileage project. Most everything went pretty smooth. I got up to regrounding my maf and testing my TPS voltage. MAF reground went smooth. TPS voltage was normal.

Now the fun begins. I get in my car and start it. It runs fine. I turned my key to the OFF position and then turned it back to the ON position (w/o starting the car) to reset my radio (I had disconnected the battery before), and I turned the key back to the OFF position. ALL my dash lights except for the "CHECK ENGINE" light stayed on and were dim, and my ECU started making loud BUZZING noises. I'm like WTF. The only ways to stop the buzzing and turn the lights off (that I found) are to either disconnect the battery or crank the car over/start and then immediately turn the key to the OFF position. The car still started and ran fine so I figured I'd mess with it later.

I then proceeded to check my fuel filter for clogging. No clogs found. I re-installed the filter, re-installed my CAI, connected my MAF, and now I can't start the car. No clicks or anything indicating a dead battery. Battery voltage is stable (or was, now after MUCH troubleshooting and searching, involving many start attempts, it's reading like 11.??? V). I couldn't figure out what the hell was wrong, so I just put it all up and searched on here for "Car Won't Start" threads.

I go out there today to troubleshoot. There are no blown fuses. I'm getting plenty of fuel. I still need to re-check some grounds and such. I checked the ECU and got code 21 - Ignition Signal. I did the "take the spark plug out, connect it to the plug wire, and connect it to ground and crank engine to see if there's spark" test, and low-and-behold NO SPARK.

Now my question is how do I approach this situation. Where would be a good starting place? Coil? ECU? Power Transistor? Alternator even? The buzzing ECU is worrying me. I seriously hope that's not the problem. I'm still somewhat of a newbie at troubleshooting. I'm the type where you tell me what to fix and I'll fix it. I've done some troubleshooting but not much. Now I do have an ignition rotor problem. It floats. Somehow the mounting screw became stripped and now it won't tighten all the way or loosen all the way. The car ran "fine" with it like that. I took the cap off to check it and it's still in the same condition as it's always been. Could this be a/the culprit? From what I've read, I'm thinking either coil or power transistor. Of course, I still need to troubleshoot my ECU buzzing.

Please help! I'm stuck at home, hitch-hiking, or bumming rides from friends until I can get my car back up and running.

Don't you hate it when this $*&# happens only mere moments after filling your gas tank up?!

Thanks in advance for ANY help or advice.

I've blown an ignition coil in my CRX and my GA16DE Sentra, but never an NX - I had a similar weird sh*t occurence and then pop went the coil - no more spark. that's where I'd start. Also, it seems that you may have a short somewhere - triple check all your connections. Are you sure you didn't do anything else? Stupid question, but the wire you grounded for your MAF, it was the correct wire right? 11V sounds a bit low but I don't know if that would stop it from starting.

REPRESENT HACK SAWED SHIFTER ;-)

Don't you hate it when this $*&# happens only mere moments after filling your gas tank up?!

Man, you don't even know how much I understand.

I would first replace the plugs, cap, and rotor. I know its unlikely, but cars are weird like that sometimes. Next try to get your hands on an extra ECU, or borrow a friends. If that doesn't work then you need to change the distributor in my opinion.

Report back and let us know what's going on.

Are you sure you didn't do anything else? Stupid question, but the wire you grounded for your MAF, it was the correct wire right?
Well, I did do a lot of other maintenance crap, but I just listed the last few things I did before I started having problems. I checked vacuum lines, re-gapped plugs, cleaned EGR/BPT valves and such, cleaned throttle body, checked for leaks, adjusted timing, adjusted base idle, etc etc. I regrounded my MAF using the white middle wire/pin/connector/whatever you wanna call it, and I routed it back to the stock ground lug on the intake manifold. Actually, there are two ground lugs there with one ground being made at each lug by two connectors that branch from one harness (yes, even my brain farted as I was trying to type/read this sentence!). Does it make a difference which one I grounded to?

I would first replace the plugs, cap, and rotor. I know its unlikely, but cars are weird like that sometimes. Next try to get your hands on an extra ECU, or borrow a friends.
I definitely need to replace the rotor (because of the stripped screw and crap), but all three probably have less than 4,000 miles on 'em, as I replaced them less than a year ago. I had to re-gap my plugs, because I found out you're only supposed to gap 'em at .044" if you have PLATINUMS and I have COPPERS. So I had to re-gap to .035". I'm also thinking that I should try a different ECU. Maybe I fried it somehow, and that's why it's buzzing like it is. I mean it's a LOUD buzzing noise, clearly audible. I've never heard of an ECU doing that, but as the saying goes, "you learn something new every day."


Now when I was looking to make sure that the coil harness connector didn't come undone there was a black plug with nothing connected to it right under the coil connection on the harness (it doesn't even have an extension of wires, it's just the connector sitting there bulging out of the harness). Is this supposed to go to something? I'm thinking I may have knocked this plug loose while trying to get at the fuel filter or something.

I did a more extensive search on the "Code 21" error, and it turns out that most threads label the power transistor as the culprit. I'll check that out, too.

Thanks for the help guys!

REPRESENT HACK SAWED SHIFTER ;-)
LOL! Yeah, I just went crazy with the hack saw one day. I love my shifter. With the RedLine tranny fluid, there was really no noticeable difference in shift leverage. With my new knob, it reminds me of a Z32 shifter. My hack-sawed exhaust sounded really good, and it gave a very noticeable SOTP increase in power. I closed it up recently, due to my audio/subwoofer install. The droning was just too loud, and it would mix with my bass. Don't *&^% with my bass, man! LOL!

You know, I just thought of something. When I read up on testing the TPS Voltage, I remember the procedure stating that the two test probes shouldn't touch. I also just read in my Chilton's manual that should your test probes touch when testing the ECU, it will short circuit and cause damage to the ECU's power transistor. My ECU buzzing/dash lights problem came about right after I got done re-grounding my MAF and testing the TPS. I don't recall ever letting the voltmeter probes touch, but had they, could this be my problem with the ECU, and ultimately, my problem starting the car? Thanks!

NO START PROBLEM SOLVED! Turns out the little clip that holds the harness connector to the coil in place and plugged in broke off sometime in the past, and when I went to remove the fuel filter I must have knocked the connector down a little bit, causing the coil to not get power.

Also, I am no longer getting any codes, including code 21, however my ECU still makes that loud buzzing noise and the lights on the dash still come on whenever I keep the ignition in the ON position (without starting the engine) and then turn the car off.

What the hell is going on with my ECU? I don't understand it ... Please help! Like I said before, it only began happening after I regrounded my MAF and checked my TPS voltage. I'm thinking I may have accidentally let the voltmeter probes touch while trying to look at the voltmeter readings.

Thanks for all of your previous help, guys, and thank you in advance for any future help!

Well, there is a relay on the ECU bracket, its green IIRC. I'll look in my FSM when I get home tonight and post up tommorow what its for.
~Ryan