2010 Aveo5 getting much better mpg after spark plug "recall" and k&n filter

Earlier this year I got a notice from GM about a spark plug recall, which I'll copy/paste in the bottom of this post. After I got it done, I noticed better MPG and a little more pep. I wanted more so I grabbed a K&N air filter and installed that. Again, there was a very slight difference in the cars throttle response time. Along with the pep my MPG improved from about 24 or 25 city, 31 highway (before the spark plug recall) to 27-29 city 37-38 highway (after the recall). :p

If you have a 2009 or 2010 Aveo, I recommend getting the recall service to improve the MPG. Has anyone else seen better MPGs after the new plugs were put in?



" This notice is to inform you that General Motors is conducting a voluntary emission recall that includes your vehicle.

Reason for This Recall: General Motors has decided to conduct a voluntary Emissions Recall involving all 2009 model year Chevrolet Aveo vehicles equipped with a 1.6L gas engine. A degraded connection between the spark plug boots on the ignition coil assembly and the spark plugs may cause the illumination of the Check Engine Soon light, rough engine operation, and lack of engine power.


What Will Be Done: Your Chevrolet dealer will install new spark plug boots and spark plugs. This service will be performed for you at no charge.

What Should You Do: Please contact your Chevrolet dealer as soon as possible to arrange a service date and to assure part availability. Instructions for making this correction have been sent to your dealer. Please ask your dealer if you wish to know much time will be needed to schedule, process, and repair your vehicle.


The new GM spark plug number and new spark plug gap are listed below. Please update your owners manual or place this letter in your owners manual for future reference.

New spark plug number: 25186682
New spark Plug gap: 0.031-0.035 inch (0.8-0.9 mm)"

I'm glad you had such an improvement after having the recalls performed. Thanks for updating. I will pass this on for GM. Do contact us if you have any concerns. Have a great week!

Matt,

GM Customer Assistance

I didn't see any change at all to the boots or springs myself, but there was big changes to the plug itself. That coil is still being used in the 2012 Sonic....it appears you have a 2010. I think there is a production break in the 2010 model year the head and the exhaust camshaft or camshaft pulley were changed up. It would be really interesting to see if you had the before or after production change 2010 engine.

The gap adjustment can be crucial to proper engine operation. A narrow gap may give too small and weak a spark to effectively ignite the fuel-air mixture, but the plug will almost always fire on each cycle. A gap that is too wide might prevent a spark from firing at all or may missfire at high speeds, but will usually have a spark that is strong for a clean burn. A spark which intermittently fails to ignite the fuel-air mixture may not be noticeable directly, but will show up as a reduction in the engine's power and fuel efficiency.

If the boots were the problem...why change the gap? And firing tip? Looks like they aren't sure so made several changes to correct the misfiring.

i think i heard the gap change is due to them changing the plug type. But i have not had someone with the recall pull their plugs to verify that.

Quote:

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Originally Posted by petrified.rabbit

i think i heard the gap change is due to them changing the plug type. But i have not had someone with the recall pull their plugs to verify that.

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A motor built in 2009 that didn't come from the factory with platinum or iridium plugs is odd. A smaller gap, and it's a small gap by today's standards is also odd, changing it now is REALLY odd...and yes the firing tip is changed as well.

I think if a person stood back and looked at all these oddities they would arrive at a conclusion: that being something like combustion chamber temp is too high not saying that's it, just saying all the oddities if you look at them one by one......all those changes produce the same result independently.

If the boots and springs were the problem, why the dramatic plug changes and as I said the new and old boots and springs look identical, same markings on the new boots as the old boots, maybe diff material but I say not.

I am going to have to examine my numbers a little better. Post recall I had a significant improvement in my average fuel economy but have noticed a recent decline now as the weather gets colder. My last 4 fills have been worse than my overall average and I think 2 of them are close to if not the worst economy I've gotten.

well changes to the "post" recall spark plugs sure don't do anything that would improve mpg, a smaller gap would create a smaller spark and in theory a smaller explosion and that equals.....less power, more emissions. There can also be a fluctuation in the ethanol percentage of the gasoline, depends were you fuel and the old supply and demand plays apart as well but there can be 0% up to 30% ethanol depending on the situation...more ethanol means less mpg for your car.

And my Aveo in the winter with all synthetic fluids, trans,engine and power steering gets between 21-27mpg.

There has been rumours that different spark plugs (construction, composition) have been having an effect of fuel mileage dependant on geographic area (different fuel composition). I didn't really buy into it though I did end up observing a jump in fuel economy after the recall. The new plugs were a very different design than the old ones. I may have to start looking in other directions though, different fuel supplier or something. My driving style does not change, I make the same 390km drive every fill (2 trips to work) and weather conditions have been favourable lately. It's a real piss off that the price of fuel goes down and so does my fuel economy.

most recent MPG with cool down in outside temp. 37.759/L for 455 KM, 356 highway cruise set last 99 city. 28.27 MP us gallon by my calculator and that's with premium gas/all synthetic fluids/K&N air filter.....so still not far off the 27 it got when it was new, another couple weeks and I will be back to the 21 mpg when it really gets cold.

I'm running a 2010 Aveo sedan (1.4L) on E20 and I'm getting 33mpg city, no highway. I'm in Thailand, so no recall, out of interest what spark plugs are now recommended? I guess if I knew the part number or type I could just buy them myself and test. I'm always interested in getting better economy; I have a scan guage e and K&N filter so if anyone could let me know, thanks.