Hesitation/Misfire?

[DocL]

Last year after I washed my car the engine started to misfire and run like cr@p. I noticed water all over the rear of the engine and contributed it to the coilpacks getting wet. After a week or so of drying out, the car ran fine. Fast foward to a few months ago and the same thing happened. This time the CEL went on. Ended up being a bad rear O2 sensor which was replaced and the car ran fine. Yesterday I go to drive the car and it is misfiring again, but not as bad as previously. I've only replaced the plugs once and the coilpacks or original.

Does this sound like it's time to replace the coilpacks and or plugs at the same time? Where is the best place to by coilpacks for my '94?

-TIA

 

[goldNSX]

Maybe igniter unit.

 

[DocL]

Is there an easy way to check?

 

[goldNSX]

From what I've read: try with good one. Those are difficult to check as they fail under vibration.

 

[DocL]

I replaced the igniter and the problem still exists. I'm thinking the coils and plugs need to be changed. There is no CEL.

 

[ATERPAK]

I had the same thing. Over a lot of testing, I found that it was the plugs first which seemed to help out the most. I also had the injectors cleaned and tested. They rarely go bad but sometimes get dirty or uneven in how much flow each puts out. That really helped along with the plugs. So far all seems to be well.

The plugs are easy to change so do that first. If you can borrow a set of good coil packs then do that. Try changing one at a time because it might just be one bad coil pack. If that doesn't fix the problem then look at the injectors. It only cost me $50 to get them cleaned and tested so that wasn't expensive and not real difficult to do. Make sure your fuel filter is up to snuff. Rarely the problem. From there if it isn't fixed talk to Larry. He's the Guru on the site. However I wouldn't change out the fuel pump as he might suggest unless it's stumbling under a heavy load. Good luck,

Al

 

[DocL]

Thank you my fearless leader. I'm going to spend some quality time with my girl in the garage this weekend.

I guess this is payback for not driving the car more than 1k miles the past two years. I won't make that mistake again.

 

[Larry Bastanza]

As Al suggested I would not "shotgun" the fuel pump. If there is a suspicion about it, you MUST test fuel pressure. Best way is to connect a fuel pressure gauge in a way you can drive the car and observe it, before you decide to just swap it out. It is a bunch of work, and $$.

Regards,
LarryB

 

[m3456y]

I've had the same problem and finally replaced all of the coil packs.

I have 5 known good ones for an early ('92) NSX if you are looking for some. They have 28,000 miles on them.

Both times on my car the culprit was the rear driver side coil. The rears get most of the water abuse. This time after changing plugs and coils as well as new coil cover gaskets - I ran a bead of clear silicone along the top edge of the rear coil cover before I installed it. I don't think it will leak again, and it should still be easy to remove.

 

[Larry Bastanza]

I've had the same problem and finally replaced all of the coil packs.

I have 5 known good ones for an early ('92) NSX if you are looking for some. They have 28,000 miles on them.

Both times on my car the culprit was the rear driver side coil. The rears get most of the water abuse. This time after changing plugs and coils as well as new coil cover gaskets - I ran a bead of clear silicone along the top edge of the rear coil cover before I installed it. I don't think it will leak again, and it should still be easy to remove.

Did the cover have the top gasket?

 

[Honcho]

Thank you my fearless leader. I'm going to spend some quality time with my girl in the garage this weekend.

I guess this is payback for not driving the car more than 1k miles the past two years. I won't make that mistake again.

I am glad you kept the car, Rob. Now drive it!!

 

[m3456y]

Did the cover have the top gasket?

Yes, I replaced top gaskets on both. I was using polished billet covers though, so that may have had something to do with it.

 

[ATERPAK]

DocL,
I love your byline about education. Truer words were never said. There seems to be two ways to educate oneself. The easy way, or the hard way. The hard way is always painful in one way or another. Usually in the pocketbook. :wink:

Good luck with your trouble shooting.

Al

 

[DocL]

Well folks, my problem is solved.

As I suspected two of my plugs were extremely fouled and two of the coilpacks were burned and c@ppy looking on the rear bank. There was water in two of the spark plug holes and when I removed the plugs the smell of fuel was overwhelming.

I'm going to replace the plugs and coilpacks on the front bank tomorrow and enjoy a nice drive. I'm pretty sure I was down at least 50hp the past few times I drove the car, and that was one reason why I didn't enjoy driving it as much.

Oh yeah, a big THANK YOU to m3456y. He shipped me five coilpacks which were in great condition. It's good to know that we still have a few honest and helpful people on Prime.

One last thing. I'll be keeping the NSX hopefully for a verrrrry loooong time. The 996 TT was sold last month.