Stuttering at WOT

[Spoolin98]

So after doing a ton of reading on plugs/gaps/wires Im still lost.
There are some threads saying use BPR and some saying BR plugs. Some say gap to .028 and some say go tighter to .020.

I was having a stuttering issue at WOT around 6k, it sounded like a 2 step rev limiter.

MSD wires with stock coils.
FP Green at 20-22psi
Im using BR7ES plugs, they were gapped to .020.
I pulled the plugs and tried a smaller gap just to see what would happen. I gapped them to .018, now the stuttering went away but now my CEL is flashing showing knock in 3rd gear at WOT when it wasnt showing knock before.

My question is, is this too small of a gap?
Could my wires be going bad hence why I need such a small gap?

I have MY1GDSM from here remote tuning my car. So if your going to ask any tuning questions, I probably wont know the answer because I know nothing about tuning. Hence why I paid him to tune it.

Any input is much appreciated. Thx!

 

[Roberti 2G]

Could just be your knock sensor going bad and just happen to give you the issue now.

 

[Spoolin98]

I doubt that, it has less than 7k miles on it.

 

[snowborder714]

Are you able to post up a log while this is happening, Mike?


I doubt you need to go with that small of a gap on pump gas. I'd try between .020" and .024".

 

[Spoolin98]

Post a log of the stuttering or the CEL?

Im sure My1gDSM will fix the cel light problem as soon as I send him some logs.

Im just confused as to why after changing the gap am I getting knock? And Im trying to figure out why my gap has to be so low to prevent stuttering at WOT.

Here is a log from last night when the gap was still at .020 and the car was stuttering in 3rd.

Well I had it at .020 and it was stuttering, I didnt think going any larger would help...

Another pull from last night

 

[snowborder714]

Ya, log doesn't really show anything.

I'm sure the tuner will take care of the CEL - I was more curious if anything around the stuttering was showing up.

I'd also say to test your plug wires. You can get a multimeter and check resistance on each wire (Ohms). Just keep in mind the longer wires will see a bit more resistance than the shorter ones. This way you can at least see if one of them has a ridiculously high reading.

But I still don't think you should need that small of a gap. But if it's working to keep you from stuttering, then run it! Just make sure you don't feel anything else funky because of it possibly not sparking with that small of a gap.

 

[Spoolin98]

Its actually running fine with that gap, its pulling hard except for the CEL im getting.
I think I get more phantom knock then real knock.

 

[Spoolin98]

Im planning on testing the wires and coil packs, i ran the motor in the dark and sprayed a mist of water over the wires and coil packs and didnt see anything.

Im still wondering why I have to gap the plugs to .018 for the car not to stutter under boost. I tried a brand new set of BP7ES plugs gapped to .025 today and it stuttered everytime i went into boost.

Here is my question, if anyone can answer it.
If you have bad wires or bad coil packs, would that cause you to gap your plugs really small, say .018, to get the car to run at WOT without stuttering?

I was also thinking about trying a set of BPR7ES plugs and see how it runs on those.

 

[Tiki2777]

I would maybe try to run the bpr7es because they are designed for turbocharged applications. If that doesn't work i would try a colder plug like bpr8es.

 

[Spoolin98]

I just wanted to post these results.

Coil Packs tested, According to my manual, primary resistance should be .70 to .86 ohms and mine were 1.0 ohm even, could this be a problem?
secondary resistance should be between 11,300-15,300 ohms.
Mine were 14,200 and 14,300 ohms.

Tested the wires, all of them were less than 100 ohms with the longest wire being closest to 100.

I bought new NGK wires anyway just to be safe.

 

[Calan]

Here is my question, if anyone can answer it.
If you have bad wires or bad coil packs, would that cause you to gap your plugs really small, say .018, to get the car to run at WOT without stuttering?

It could definitely cause an issue like that. If your ignition isn't producing enough current to jump the gap under high cylinder pressures, then you have to either shorten the gap, reduce the cylinder pressure (less boost or a different air/fuel mixture), or get more current to the plug (better ignition system).

Coil Packs tested, According to my manual, primary resistance should be .70 to .86 ohms and mine were 1.0 ohm even, could this be a problem?
secondary resistance should be between 11,300-15,300 ohms.
Mine were 14,200 and 14,300 ohms.

Keep in mind that a DC resistance check can tell you if the coils are bad, but it won't necessarily tell you if they are good. Ignition coils are inductive devices working at very high voltages; it's possible for them to pass a coil resistance check with a VM but not work properly under normal operating conditions.

 

[Spoolin98]

I put new BR7ES plugs in gapped them to .022 with new NGK wires and it drove great, no stuttering and no cel.
Must have been bad wires the whole time...

 

[GSXDNA]

Im planning on testing the wires and coil packs.

I had a similar issue. Did you check the power transistor along with the coil packs? I bought a new power transistor and gapped my BPR7ES' to .022, and so far today (first day since the re-gap) it's run much better.

 

[Spoolin98]

I dont even know what or where the power transistor is

 

[talontd92tsi]

I dont even know what or where the power transistor is

Should be right next (underneath) your coilpack. (At least it is on the 1g cars)?

 

[snowborder714]

Glad to hear the problem went away!

Power transistor

 

[ricktb]

The ideal gap is .028" and those plugs sound ok. I had a similar problem, stuttering while under WOT. However I found my plug gaps were between .045 and .085, and once I regapped to .028 it ran smooth, and more power. I am also running iridium plugs, they are good. I read on here copper ngks are best.

 

[snowborder714]

.028" is not necessarily the ideal gap. It's the largest gap you should run on a turbo car (and it's the factory spec: 0.28-.030"). However, if you're running higher boost and blowing out the spark, you may need to gap it down, as Mike has done.