My NSX is having intermittent mis-firing

BATMANs said:
I've pressure washed my NSX and had no problems. The last time was about 10k miles ago. Now, I'm wondering if i did install the cover upside down.
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Have you pulled the coils on the rear most bank towards the trunk? That is were I found my misfire problem. Took the coils out and dried they were fine, but I'm guess if you had them in there for a while they may have rusted & gone bad? I had my engine cover in place as well when I developed the problem.
 
I believe the coil packs are specific only to front or back bank because of the direction the plug is on. You'll clearly see this when you remove the two screws holding the cover over the coil banks. The coil most likely to go bad are the ones on the rear bank where the rear window garnish is over. Removing the RWG will greatly improve access to the rear coil banks. You can individually unplug one, one at a time to troubleshoot the coils while it is showing it's symptoms. Check to make sure the plugs are tight too (Somehow, I had a plug lose before) .

If it is a bad coil, it's probably because you're missing the gasket on coil cover, or possibly upside down.
 
Yeah next time I mess with plugs i'm definitely removing the RWG first. I've got bruises all over my arms.

I drive my car in the rain and wash it often and all of mine were bone dry.
 
The coil packs are NOT specific to a cylinder or banks of cylinder (ie- wire length, etc). I would swap the coil pac before investing in spark plugs as spark plugs seldom fail electrically.
 
You can definitely swap the front and rear banks for the coils but they do have different part #'s. If he was to buy the coils, I would rather buy the coil that has the correct part#.
 
Fill some injector cleaner into the tank to see if the problem clears up. My intermittent misfire was actually caused by clogged injectors.
 
Remember to always torque the spark plugs :wink:! The manual says no antiseize compound, but I use it sparingly whenever 2 dissimiliar metals contact each other. My $.02.
 
s14_tat said:
You can definitely swap the front and rear banks for the coils but they do have different part #'s. If he was to buy the coils, I would rather buy the coil that has the correct part#.
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I run Redline SI-1 injector cleaner every time I change my oil, so I think I should be OK on the injectors.
 
I had the same intermittent mis-firing problem under load. Using my OBD2 code reader I was able to identify the misfiring cylinder #. I swapped the coil pak with the trouble code with a nearby coil pak and guess what...the problem jumped to the coil pak that was previously without an error code. I purchased a new coil pak, installed it, and no more intermittent mis-firing.
 
As you only feel an intermittent misfire, I believe that it is only one coil pak that is misfiring. If you do not have an OBD code reader they are priced at about $60 dollars these days and are simple to use (Actron is a good brand). They can assist with diagnoses of your misfire and save $$.
 
dalybo said:
As you only feel an intermittent misfire, I believe that it is only one coil pak that is misfiring. If you do not have an OBD code reader they are priced at about $60 dollars these days and are simple to use (Actron is a good brand). They can assist with diagnoses of your misfire and save $$.
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Actually costco now sells ODB2 readers for $30 that you can pretty much return anytime.

My NSX is a '93, so it's an OBD1. Is there anything that will read that for the general public or is it a dealership item only?

I don't have any CEL that went off.
 
BATMANs said:
Actually costco now sells ODB2 readers for $30 that you can pretty much return anytime.

My NSX is a '93, so it's an OBD1. Is there anything that will read that for the general public or is it a dealership item only?

I don't have any CEL that went off.
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OBD1 on my other vehicle, you could read the codes by jumping a terminal w/ a paper clip and counting the blinking of the CEL. Generally if it's OBD1, if you're not getting a CEL, then there's nothing to read.

Before you buy anything, just unplug one coil pack at a time. If it gets worse, the current pack is fine. If it's the same, it's probably the bad one. Or buy one and swap it out one at a time until it runs smooth again.
 
FogCityNSX said:
.....Before you buy anything, just unplug one coil pack at a time. If it gets worse, the current pack is fine. If it's the same, it's probably the bad one. Or buy one and swap it out one at a time until it runs smooth again.
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The thing is that my mis fire is intermittent and almost not apparent during idle.

it's when I get under load - WOT that it starts to misfire. But that's not even consistent too.
 
BATMANs said:
The thing is that my mis fire is intermittent and almost not apparent during idle.

it's when I get under load - WOT that it starts to misfire. But that's not even consistent too.
Click to expand...

I've had a lose spark plug that did that. It had carbon build up all around the spark plug and around the part of the coil that reaches into the head. At idle it wasn't noticeable, but at underload and higher RPMS, the revs were rough and everything would just blow through the loose threads. Ironically, it was also the one single coil that had rust around the mounting bolts because of water.

Friday night is here, spend an hour or two just pulling plugs and coils. Maybe hit up some double D coffee afterwards to relax afterwards lol.
 
Dear Batman: I just read your last post on Feb 26 as follows: "The thing is that my mis fire is intermittent and almost not apparent during idle. it's when I get under load."

This is exactly the symptom that my 1996 NSX had before I replaced the one bad coil pak.
 
MY NSX hit 70K, I bought with 58K (not DD but still managed on a year an a half to put all this miles), have washed WAY to many times, and I driven on the rain -since in FL RAINS everyday almost from April to November- sometimes, so my guess is that somehow after 70K miles the coil gaskets/cover w/e doesn't isolate anymore the water, so after a wash or rain, next day my nsx POPS POPS POPS .. really irritating -started at 70K-, leave alone power cuts, after driving some hours water evaporates and is fine.

So what I do is put a towel on the top the engine right on the rear were the water goes down, and is AMAZING how the towel gets wet, kinda scary actually, so now I wash NO PROBLEM, the problem is the rain while driving :( ...

I'll make a custom cover so the water gets there and drops to the floor, such stupid design flaw this is, is kinda the taillights that have water REGARDLESS gaskets or how new the Taillights are .. honda LOL

Oscar
 
This looks like it's ready for another purpose..... when you see a major NSX repair/mod bill.

attachment.php
 
Talk about pucker phactor...YIKES :)

BATMANs said:
This looks like it's ready for another purpose..... when you see a major NSX repair/mod bill.

attachment.php
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