Update on hesitation problem.

[pattejam]

Hello,

My 91 has been hesitating/misfiring pretty bad when the car gets up to operating temperature. I ran the codes on it last night and nothing came up. I recently changed the plugs, so they are new. It runs fine when it is cold, but bad when heated up. It is a hesitation in all gears,

Does anyone have any thoughts?

thanks in advance

Cory Patterson

 

[19inchNSX]

Have you checked the direct ignition packs? If you have any of the igniton packs reversed from the front bank to the rear bank, it could result in mis-firing.

 

[Poloman]

Have you checked the Cats and O2 Sensors?

 

[johndoh]

Spark Plug wires?

 

[ewarman]

Tell me when you find the spark plug wires.

There are no spark plug wires. There are six coil packs that are directly on top of each spark plug.

 

[Kinan]

Did you install OEM plugs or aftermarkets?

I had a problem when I tried to install DENSO Iridiums. It seems they (and other) aftermarket plugs have the top end caps of the plugs that screw on rather than fixed solidly in place like the original plugs. Because of this, the little end caps are hollow in the middle all the way through.
The electrode from the ignition coils is small enough in diameter to fit INSIDE of these threaded holes which makes for a less than optimal connection. I first heard a lot of popping in the FM radio. AM worked fine.
I found screws that matched the threads of the end caps, tightened them in real good then cut the ends off flush with a Dremel cutoff wheel and sanded smooth with 400 grit. Worked fine after that and still does 10k miles later.

 

[pattejam]

Hello,

Thanks for the replys. This weekend i am going to check the resistance on all of the coil packs to see if one of them is going bad. I think that i remember from science class that increased temperature = increased resistance.

Maybe one of them is on it's way out. I will also check to make sure one of the packs isn't reversed.

Wouldn't a faulty O2 sensor show up by running the ecu codes?

My car has 60,000 miles on it. Should I have the cats looked at?

Oh yeah, I used NGK's for plugs. The ones that the car came standard with.

Thanks

[This message has been edited by pattejam (edited 31 January 2002).]

 

[DanO]

I think the coil resistance should be tested when the coils are at 77F. See www.danoland.com/nsxgarage/spark_plugs/spark_plug.htm for more info.

DanO

 

[pattejam]

PROBLEM SOLVED!!

Well, I took everything apart last night and when i went to pull the plugs out, one seemed loose.

I went ahead and tested the coils anyway (thanks DanO) and they all checked out. I gave everything a nice squirt of dielectric grease and tightened the plugs in good and fired it up.

Everything runs great now. I didn't realize how much I missed her!!

I guess when the heads heated up, it allowed the cylinder to leak a little bit past the loose plug.

The thing that really got me was that it felt like it was the same problem as before (needed new plugs) so I assumed that they were ok. Live and learn i guess.

Thanks for everyone's help.

Cory Patterson