My car started running very jerky/hesitant about 1/4 tank after being tuned. I took the plugs out and this is what they look like. They are the NGK R6725-105 race plugs running 110 octane leaded race gas. IMO they look like they've been severely overheated but I don't know what this residue is. I made sure the wires were all tight (new OEM NGK), cleaned the plugs and drove it again. The first few times it was just as jerky as before, then it started running fine again.

Has anyone seen this before? Is there something wrong with the fuel I'm using? These plugs are $34/each and should last more than 1/2 tank of fuel (including tuning) shouldn't they? Any help is appreciated, thanks.

 

[QUOTE=Mills;8711431]My car started running very jerky/hesitant about 1/4 tank after being tuned. I took the plugs out and this is what they look like. They are the NGK R6725-105 race plugs running 110 octane leaded race gas. IMO they look like they've been severely overheated but I don't know what this residue is. I made sure the wires were all tight (new OEM NGK), cleaned the plugs and drove it again. The first few times it was just as jerky as before, then it started running fine again.

Has anyone seen this before? Is there something wrong with the fuel I'm using? These plugs are $34/each and should last more than 1/2 tank of fuel (including tuning) shouldn't they? Any help is appreciated, thanks.

Give us some more details.
Premix ? What oil, what amount ?
How long did the car sit prior to running last ?
Were you using these plugs on the track or street ?
What brand of 110 ?

 

Were you driving on these plugs before the dyno session? What rpm was the bucking at? Was it only under boost? If these plugs weren't fresh before the dyno I would try cleaning them back up and putting them back in. It could just be a coincidence...

 

I'm running 1 oz/gallon premix of Injex TC-W3 with Torco purple 110 race gas. The car had been running/driving prior to putting these plugs in just before tuning/dynoing by Steve Kan but I wasn't boosting it, just driving it around with the factory 9s in it. These plugs were new and have 1/4 tank of tuning on them and ~1/4 tank of street driving on them.

I only noticed the bucking under boost at first, then noticed it was doing it under vacuum as well, just not nearly as bad.

The gunk smeared like water when I wiped it, then I took the plugs to a wire wheel and put them back in, they cleaned up pretty good. The first few times I accelerated it still hesitated, then the next few times it pulled fine all the way to redline.

Then it started snowing here and I've just let it sit inside since last Friday. I wanted to drive it hard some more and pull them out again but haven't had the chance yet...

 

Do you have any knock sensor readings to list when there "bucking" happens? In my mind it's looking toward an ignition problem or it could be injector related...

 

No, is that something I could read on a laptop off my Haltech e6k?

 

Looks like someone threw some carmel candy down the intake for ya.

 

Oil and water on the plugs. Are you running A/I Greg?

 

If it's carmel, and sticky, it's bad fuel. Check your intake for the same signs.
BTW, Torco is out of business. How old is this fuel.

We had some problems a few years back, with fuel made by Nutec. Some of that problem was water in the fuel. It coated everything in the motor. The water, mixed with the chemicals in the fuel, made it gum up.