[beskhu3epnm]

you do realize I'm talking about getting 5-6MPG less than I got in the same/similiar conditions last year vs this year? I think a lot of people are missing that point...
My normal winter drop for this car was 2 MPG.
How many times has that been said now?!

If your main suspect is the intake, rip it apart (or have the stealer do it) and tell us what you find. Head to an alignment shop, check your parking brake, check for sticking calipers, check your plastic underbody tray. Hell, it could be some play in the front bushings that allow the alignment to change under load, and thus at highway speeds causing more drag. If you've done all this, then there must be no reason.

If this was a car that had been around for more than 1 year, there would probably be an answer to your concern. Perhaps you can be on the leading edge.

Obviously nobody has anything left to say to you as we'd all be at a loss to offer any further advice. You will be the architect in solving this problem...

 

[RacingTiger03]

Quite correct, beskhu. I've checked everything external to the engine except alignment, and that'll be done in a couple of weeks when I get new tires. After that I'll worry about tearing into the intake, lol.

 

[jon2002]

Try two sequential bottles of Chevron fuel system cleaner. Only will cost you a couple bucks, won't hurt anything, and you might get some of your mpg's back.

 

[JITB]

you do realize I'm talking about getting 5-6MPG less than I got in the same/similiar conditions last year vs this year? I think a lot of people are missing that point...
My normal winter drop for this car was 2 MPG.
How many times has that been said now?!

Wear and tear, tire wear, alignment, winter time, brake wear. All effect that mpg. My post was more of a statement that I don't think anything I physically wrong, but the car has alot more wear on it now then it did last year. It's not outrageous to see that drop in mpg at 30k+, a good de carb service would help at that mileage. If you know a friend that works at a dealership see if they can hook you up and do one for you. Or else you are looking to spend 160-200. On a real good de-carb service. The additives work overtime, but by the time they do work you spend as much as the de-carb service.

 

[S100Y]

Only 1 mpg drop in November compared to summer, it has 19k miles and I drive it more aggressively now compared to last year. The only thing different is I added Tecron fuel cleaner recently which resulted in a noticeably smoother and responsive engine performance. RT03 you may want to try it.

 

[RacingTiger03]

Thanks S100Y. I'll grab up a bottle of the Chevron cleaner and see if it helps mixed with a tank of premium. I had thought with the DI it would make no difference, but apparently something with the valve timing allows some fuel to get over the valve for cleaning on certain cycles occasionally, lol.
Hopefully it will help. Just took another 200 mile trip and chimed in at 33 for the trip... one that use to ring in at 38+ easily. (I.E. not trying and not putting around at 60-65) Now even trying - 33. -.-

 

[RacingTiger03]

Wear and tear, tire wear, alignment, winter time, brake wear. All effect that mpg. My post was more of a statement that I don't think anything I physically wrong, but the car has alot more wear on it now then it did last year. It's not outrageous to see that drop in mpg at 30k+, a good de carb service would help at that mileage. If you know a friend that works at a dealership see if they can hook you up and do one for you. Or else you are looking to spend 160-200. On a real good de-carb service. The additives work overtime, but by the time they do work you spend as much as the de-carb service.

Gotchya, that makes more sense, lol. That's what I was thinking along the lines with the intake cleaning and such. I know on some brands it's regular maint. at around 30K.

 

[S100Y]

Thanks S100Y. I'll grab up a bottle of the Chevron cleaner and see if it helps mixed with a tank of premium.

RT03, I only use regular 87 octane gas, not premium. Filled gas today, previous tank gave exactly 30mpg with 65% city driving , lot of lights and stop signs. I also thought Tecron would do nothing for DI engine , added it as I figured it would'nt harm either but was pleasantly surprised by the engine smoothness and responsiveness. I would be more curious to see how Techron does in severe winter months of Jan/Feb because last year my mpg dropped to 27 those months and I did not use Techron.

 

[solar365]

RT03, I only use regular 87 octane gas, not premium. Filled gas today, previous tank gave exactly 30mpg with 65% city driving , lot of lights and stop signs. I also thought Tecron would do nothing for DI engine , added it as I figured it would'nt harm either but was pleasantly surprised by the engine smoothness and responsiveness. I would be more curious to see how Techron does in severe winter months of Jan/Feb because last year my mpg dropped to 27 those months and I did not use Techron.

Does the smoothness and responsiveness stay with the next tank of gas without the Techron?

The Techron is an additive that may be having the effect of raising the octane level of the tank of gas, which would cause the engine to run smoother and more responsive than 87 as noted on the octane thread.

 

[S100Y]

Does the smoothness and responsiveness stay with the next tank of gas without the Techron?

This is my third tank after Techron , the smoothness and responsiveness is still there. I intend to put Techron once more in January to cover the winter.

 

[solar365]

This is my third tank after Techron , the smoothness and responsiveness is still there. I intend to put Techron once more in January to cover the winter.

Thanks for responding. I wanted to rule that out. I'll be using some techron as well once I hit 5k.

 

[RacingTiger03]

Well, we shall soon find out. I just went in DEAD EMPTY, dumped in the BIG bottle of techron.. filled with 5.2 gallons of gas. Smells like race fuel.. NICE. Let's see if it does anything to help aside from make my nose hairs tingle....

 

[RacingTiger03]

might I just add... I wish the car acted like this all the time. It LOVES octane ... less effort to accelerate, better throttle response, little more torque a LOT sooner. ECU is aggressive little monster on this thing. That really makes me curious about what's actually acceptable to expect from a tune without eliminating the efficiency in the early cycles.
Ah well, I digress. So far according to the instant MPG, I'm getting better MPG in the same places I usually glance at it. Avg is up a bit as well, and that's not even being fair because the new throttle response has been teazing me.

(on a ramp I normally barely get to 75 on with all of us in the car.. 85 without hitting full throttle as early as I normally do!)..
*disclaimer* I do NOT recommend doing this. If you do so and blow up your engine I'm not responsible, LOL.

even after the drive to work the exhaust still had a noticeable "smell" to it. At this point I'm not 100% sure if it's an octane smell or a smell from cleaning soot and carbon off of the top of the valves. DEFINITELY seeing more white smoke than normal on AWUS starts

 

[S100Y]

I just went in DEAD EMPTY, dumped in the BIG bottle of techron.. filled with 5.2 gallons of gas. ....

That's like taking 3 days prescription meds on a single day!! I don't know if the ECU is programmed to handle so much octane, hope it does'nt do anything bad. I went exactly by the instructions, 1 bottle followed by 14 gallons of 87 gas.

 

[solar365]

Yeah RT! Go big or go home! LoL

I'll be waiting for your assessment after the next full fillup to get a second opinion after S100Y's.

 

[RacingTiger03]

That's like taking 3 days prescription meds on a single day!! I don't know if the ECU is programmed to handle so much octane, hope it does'nt do anything bad. I went exactly by the instructions, 1 bottle followed by 14 gallons of 87 gas.

Basically.. LOL.

It's not the first time I've done that, usually on motorcycles that I can't get the time to tear down and clean the throttle bodies on properly. Works magic. I was a little worried about the car with it's timing advance and compression to be honest, but it's handled it AMAZINGLY. (but if a 1L 160HP motorcycle can with 13:1 compression.. well.. surely.)

As I said, I don't recommend it to others


Solar, I agree. LOL. This was the truck dose for 22 gallons of treatment even, hah. Even my wife made a comment about the smell of the exhaust.

So far Hwy MPG is SINGIFICANTLY improved... but, hard to judge anything on this tank. I would be afraid to see the AFR at highway lean cruise right now!!!

 

[RacingTiger03]

bump,

I'm not far into the first fill after the additive, but so far performance hasn't dropped from the tank WITH the additive, and MPG is up back around 34MPG average so far this tank. That's a near 5MPG (re)gain indicated so far.. but I'm only 100 miles in, so we shall see
If this holds up, it's safe to say the valve timing definitely allows for valve cleaning, and a little boost every now and then with something like the techron/seafoam/etc wouldn't be a bad idea. For this to be effective, fuel must get to the top side of the valve, thus the concern of it not working at all on a DI engine.

Also added to OP for ease of reading.

FWIW, I opted to go with 92 octane for this tank just to ensure things are cleaned out, and hopefully KEEP it that way. As noted before, I've normally LOST MPG with premium, so these gains so far are very impressive IMO.
Loosened up (or tightened up as the case may be) with less buildup on the valves FTW!
I'll be opting for a full top-end cleaning and media blasting of the valves at 50K (BMW regular maint.) if I still have this car at that point.

 

[tickerguy]

bump,

I'm not far into the first fill after the additive, but so far performance hasn't dropped from the tank WITH the additive, and MPG is up back around 34MPG average so far this tank. That's a near 5MPG (re)gain indicated so far.. but I'm only 100 miles in, so we shall see
If this holds up, it's safe to say the valve timing definitely allows for valve cleaning, and a little boost every now and then with something like the techron/seafoam/etc wouldn't be a bad idea. For this to be effective, fuel must get to the top side of the valve, thus the concern of it not working at all on a DI engine.

No it's not.

It's equally (in fact more) likely you had one or more partially-fouled injectors and the extreme detergent level of what you ran through them restored a reasonable spray pattern.

I'll be opting for a full top-end cleaning and media blasting of the valves at 50K (BMW regular maint.) if I still have this car at that point.

I would certainly inspect before undertaking such an operation.

 

[solar365]

Glad to see you are seeing the benefit racing tiger, but I'm with tickerguy that I think this huge change is pretty much just attributed to the injectors.

Not to say there couldn't ultimately be some carbon buildup on the intake valves as well, since 2014mazda6 member said running the seafoam treatment improved his engine smoothness and had a small impact on fuel economy.

I would be curious if somebody with high miles on their mazda 6 that hasn't run any cleaners could do a borescope inspection of the tops of the intake valves to see if they are shiny clean or something else...

I'll definitely be running some techron through my engine before too long here as a routine maintenance.

 

[tickerguy]

I have ~22k on my car, have run no additives in the fuel (or anywhere else) and have no noted degradation (or any other change for that matter) in the mpg pattern or engine operation.

I do tend to run top-tier fuel when home, favoring Exxon and Shell stations (both of which are convenient to my usual stomping grounds and competitive in price.) The exception is on trips where I usually favor the high-volume stations (e.g. truck stops such as Love's, etc.)