missfire with new NGK TR6's

I was talked into putting some NGK v-power copper TR6's in my car,to replace the worn and fouled 104's..and i also wanted a heat range hotter for winter,because my mileage seems to suck with the 104's unless its summer time... gapped them at .55 and instant horrible missfiring as soon as i hit boost. Thought maybe i messed up a wire during the process,got a new set of delco wires..and nothing... A well respected car builder i know told me to gap them down to .35 ok a lot better but still not perfect...

I dont understand what the deal is....should i try a smaller gap? the car ran fine b4,just sucked the gas..

I just recently replaced my AL platinum 104's for NGK TR6, gapped at about .055 and they seem to work fine.

I would say closely check your wires. Test them with an meter if you can.
Also, I had misfiring when I hit high rpm, WOT and it was the coils that were the problem. Those were the accel coils...

One more thing, One stage colder for NGK is not the same one stage colder for Autolite. I can't remember the temperature differences I saw but I would not necessarily say that a TR6 is same as a 105

Sounds like a bad coil. I would by one coil and play musical coils hopefully you will be a able to find the problem.

turtleman wrote:

I just recently replaced my AL platinum 104's for NGK TR6, gapped at about .055 and they seem to work fine.

I would say closely check your wires. Test them with an meter if you can.
Also, I had misfiring when I hit high rpm, WOT and it was the coils that were the problem. Those were the accel coils...

One more thing, One stage colder for NGK is not the same one stage colder for Autolite. I can't remember the temperature differences I saw but I would not necessarily say that a TR6 is same as a 105

Im gonna invest in he coils...it almost sounds right.... according to the NGK book,or website the riv takes the TR55 stock....the xtra 5 means there pre gapped....so i opted for the TR6 ungapped.....seems about right to me....but thanks for helping me diagnose this problem..ill keep informed of what happens when i replace the coils....

I've run Autolite 104s all year round for over 4 years. Mileage is always worse in the winter, but changing plugs won't improve this, imo.

AA wrote:

I've run Autolite 104s all year round for over 4 years. Mileage is always worse in the winter, but changing plugs won't improve this, imo.

you dont think a hotter plug would improve?? it seems that it would since mileage is great in the summer with 104s.....hmmmm i guess its worth a shot..but either way i need to figure out whats up with my coils..

I don't think it will matter. The spark is the same regardless of heat range, but the tip stays cooler with the cooler plug. A 104 in summer burns fuel the same as 104 in winter.

I think the fuel economy difference comes from a combination of things, including longer warm-up times causing the PCM to stay in open loop longer, richer air/fuel, lubricants at higher viscosity in cold temps, etc. Plus, we just idle more in winter to stay warm, and we use more accessories for the same reason. Colder air is more dense, so more fuel is commanded, and colder air exerts more drag on a car at speed. Slush and snow cause us to drive slower and they adds rolling resistance; cold rubber tires are also not as efficient at energy transfer compared to warm. Finally, winter gas is crap!

hmmm..its just weird,i had never experienced this amount of loss untill i did my mods,i mean i usually get almost 400miles to a tank,now i get a little over 300...seems like a lot to me..

Check for small vac leaks. Did you recently change your fuel filter ? My GF's GS suffered a decrease in mileage with her new fuel filter (yes decrease). It was the WIX brand. Other people have had this issue with the wix (some people reported getting .3mpg back on the 1st drive when changing back to another brand). They are good filters..maybe too good.

Jason wrote:

Check for small vac leaks. Did you recently change your fuel filter ? My GF's GS suffered a decrease in mileage with her new fuel filter (yes decrease). It was the WIX brand. Other people have had this issue with the wix (some people reported getting .3mpg back on the 1st drive when changing back to another brand). They are good filters..maybe too good.

I did just recently change it but i used an ac delco....i had this same problem last winter.. an couldnt understand why i was getting such horrid mileage....i never had it this bad untill i put the 104's in..

UPDATE.... seems my car just didnt like the NGK's... i decided to stick with what i know...and i know a coil didn go bad,or anything else for that matter just by swapping plugs.... so i orderded in a set of AL 605's alll fixed..runs great...an im saving some gas!

Glad you got it fixed. Odd your car didn't like the TR6s?

Darn...wish I had seen this sooner.

I have seen this happen a few times before. Your car would probably like the NGK's just fine. Let me explain.

Look at an NGK and an AL where the wire clips on to them. AL's are a solid one piece design. NGK's end piece screws on. If those end pieces are loose, they will cause a bad contact and a poor spark at best.

Think I have one of each plug at home and can get pics up later.

The fix.. many will use pliers or cutters to ensure the ends are on securely before installing.

If you still have your NGK's around, check the ends of them to see if any are loose.

Glad your car is running better, Rob. But I'd like to see some hard proof that one range warmer saves even a tiny amount of fuel. If anything, colder plugs are more needed in winter to combat the knock caused by denser air and higher boost.

well put it this way i didnt have the poor fuel consumption untill i changed to the 104's.... and it makes sense being its fine in the summer an gets worse in the winter...seems to me the temps affect it.. in my experience... colder temps your going to have colder IAT's, which in turn is going to run the mixture a bit richer.....by using a hotter plug if more efficiently burns the extra fuel by creating a larger arc, which creates a more efficient flame, so it makes more efficient power and takes less fuel consumption to move the car..

Well, if it works for you, that's good news. I was reading NGK's FAQ page and came across some interesting info related to our discussion:

http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp4.asp?nav=31000&country=US

"Below is a list of external influences on a spark plug's operating temperature. The following symptoms or conditions may have an effect on the actual temperature of the spark plug. The spark plug cannot create these conditions, but it must be able to cope with the levels of heat...if not, the performance will suffer and engine damage can occur.

Air/Fuel Mixtures seriously affect engine performance and spark plug operating temperatures.

* Rich air/fuel mixtures cause tip temperature to drop, causing fouling and poor driveability
* Lean air/fuel mixtures cause plug tip and cylinder temperature to increase, resulting in pre-ignition, detonation, and possibly serious spark plug and engine damage
* It is important to read spark plugs many times during the tuning process to achieve the optimum air/ fuel mixture

Higher Compression Ratios/Forced Induction will elevate spark plug tip and in-cylinder temperatures

* Compression can be increased by performing any one of the following modifications:

a) reducing combustion chamber volume (i.e.: domed pistons, smaller chamber heads, mill ing heads, etc.)

b) adding forced induction (Nitrous, Turbocharging or Supercharging)

c) camshaft change
* As compression increases, a colder heat range plug, higher fuel octane, and careful attention to ignition timing and air/fuel ratios are necessary. Failure to select a colder spark plug can lead to spark plug/engine damage

Advancing Ignition Timing

* Advancing ignition timing by 10° causes tip temperature to increase by approx. 70°-100° C

Engine Speed and Load

* Increases in firing-end temperature are proportional to engine speed and load. When traveling at a consistent high rate of speed, or carrying/pushing very heavy loads, a colder heat range spark plug should be installed

Ambient Air Temperature

* As air temperature falls, air density/air volume becomes greater, resulting in leaner air/fuel mixtures.
* This creates higher cylinder pressures/temperatures and causes an increase in the spark plug's tip temperature. So, fuel delivery should be increased.
* As temperature increases, air density decreases, as does intake volume, fuel delivery should be decreased

Humidity

* As humidity increases, air intake volume decreases
* Result is lower combustion pressures and temperatures, causing a decrease in the spark plug's temperature and a reduction in available power.
* Air/fuel mixture should be leaner, depending upon ambient temperature.

Barometric Pressure/Altitude

* Also affects the spark plug's tip temperature
* The higher the altitude, the lower cylinder pressure becomes. As the cylinder temperature decreases, so does the plugs tip temperature
* Many mechanics attempt to "chase" tuning by changing spark plug heat ranges
* The real answer is to adjust air/fuel mixtures by rejetting in an effort to put more air back into the engine"

thats an interesting article AA...i just dont understand why it works for me then..