2009 Prius Techstream Data Log Request | Running at its best?

11 mpg and nothing obviously wrong. Like a hole in gas tank isn't this a unit that's five feet in air w tractor tires?? 11 mpg would sound about correct ..no? Or is this a bone stock unlifted daily driver ? You're the guy w metal lift spacers and underpinnings for four wheeling. Like monster trucks look?

 

Look at the long-term fuel trim. What are you seeing for your car?

 

I lost 5 mi to the gallon lifting the car 40 mm and going to 205 65 15 tires that plummeted my gas mileage to below 37 for the most part Just those two changes nothing else has changed in the life of the car the amount of driving is the same the mileage and all of that everything The only thing that changed was the lift and the tire size and it showed up immediately on the MFD like the minute I put the tires on the road and push the power button it never came above 37.9 miles an hour and this has been months now and I know that the minute I put the 195 65 15's back on the car the mileage will go up two or three miles to the gallon just from that alone and then if I put the front end back down where it's supposed to be it'll probably go back up to the 44 45 that an '07 generation 2 with 340,000 mi on it should be doing I thought Jimmy's car was you know running tractor size tires in other words tires as tall as I am and lifted feet or something similar his car looks like all the other seriously lifted Prius on the given pages I've seen them on nothing like mine in other words so I would expect that might plummet you into the 15s at least he's claiming 11 not that far off I mean when you're inviting another vehicle and that much air to drive right under your vehicle I would think that the MPGs are going to take a serious hit but that's just me apparently.

 

Well I can't easily blow that up but that looks basically like my business and yes you should be getting more than 20 mi to the gallon absolutely that looks like about a 40 mm lift and somewhere around 205 65 15 tires or close to that same outer diameter around 26 in total OD That's what my car has I don't even need to post a picture It looks just like yours basically and like I say I'm getting 37 and it doesn't budge from that when I fill it up it starts off at 41 and plummets to 37 within 35 mi on the MFD and stays there permanently unlike with the regular tire size and the front end where it's supposed to be down on the ground the same card gets 43 to 45 being driven sometimes unreasonably so there should be something jumping out at you at 11 miles to the gallon even 20 I would think just looking at her another Prius right up the street from you freeze frame data something should pop I don't know what but something I don't know if your brakes are dragging or what you've got going on but 11 mi to the gallon on a 1NZ engine I mean even if it was blown and running racing fuel that shouldn't be.

 

So then apparently your car is not serious lifted You're not with the Prius off-road crew so on and so forth apparently at least this car isn't The pictures of the Prius I have in the off-road club have tires on them almost as tall as I am and I'm not a midget they are really lifted like ridiculously so

 

So if you put the car in maintenance mode or put the heat on when the car is cold so the car won't stop running you should be able to stand behind this car and your eyes water or your sneaker soles start to melt off your shoes something I mean you ought to be burning up some fuel 5 mi to the gallon consumption rate I mean that ought to be like lighten up the tailpipe almost I would think or something that ought to stink like crazy I'd be looking at my MAF sensor and all that stuff something I'm sure you've cleaned it and done whatever but all that stuff needs another going over having to look at something maybe something shorted I can't imagine

 

Well I got 4 cars all getting 40 ish being driven .by adults the only low mileage Prius I have is one looking like yours 205 65 15 40 mm lift . None stock proper hybrid engine atkinson . . Aren't you running a Yaris motor in yours non Atkinson and so on or did that not make it to fruition I can probably send you when I figure out how to print them the freeze frame data sets I don't think there's any difference from the two that do about correct mileage in my lifted has stated above I'm going to look today but I'm don't really think so but I'm sure there must be because the numbers are different so some things different the width of the contact patch in the amount of air getting up under the front end lifting the car up or something that's why cars don't do that generally I would have to think something along those lines people have spent 70 years getting those cars down on the ground and their contact patches with the road dialed in to vehicles weight and all these other factors and here I come along and just slap some crap on the car and wonder why I'm 8 9 mi to the gallon off I don't think I'm really wondering.

 

Since it's important to learn something new every day, and my level of "confidence" is in question I thought maybe I could help narrow things just a smidgen for now.

On a Gen 2, which your photo appears to be (please correct me if I'm wrong): The downstream O2 sensor (B1S2) doesn't do ANYTHING for air fuel ratios. It's merely used to check the condition and efficiency of the catalytic converter. It provides zero information used for adjusting ratios.
The upstream air/fuel ratio sensor (B1S1), mounted in the exhaust manifold, is a wide band sensor that provides the input for the ecm tuning the AF ratio.

My tidbit for today.

 

That would be at the top of my list. If the catalyst bed is broken up then the chunks can restrict exhaust flow. The engine has to work much harder to push (pump) exhaust out.

Quick test with a scantool hooked up. Drive at around 50mph. Now accelerate full throttle to 75. What's the highest MAF and RPM readings?

On my 2006 I had about 56 grams per second at 5000RPM at 75mph.

Posted via the PriusChat mobile app.

 

That's correct for a Gen2 Prius, and for MANY other cars as well.

BUT, there is something known as "downstream fuel trim" which does use the after- cat S2 oxygen sensor to adjust fuel mixture under certain conditions. Toyota began using it on some California emissions cars in the late 80's. Now it is fairly common.


Posted via the PriusChat mobile app.