Auto stop & fall temps
My morning temps are in the 30s and 40s too. I keep the temp to 68-69 and still get autostop engaged after a couple of miles. I even shut the car down at stop lights when autostop hasn't engaged yet. Then again, my car is in a finished garage so the car itself may not be that cold to begin with.
Which then got me to thinking isn't one of the factors battery temp? If the battery is too cold (or overheats) AS does not engage. Isn't that the part of the trick behind the HCH battery hack switch to make the onboard computer think the battery's temp is out of range so assist will not occur and drain the SoC? So I was thinking has anyone tried a battery heater? Maybe something in the trunk up against the battery compartment to warm that up before they start in the morning? I don't know... this is just a thought, but it seems pretty plausable. Mythbusters where are you
Help us test the right conditions for an HCH to AS!
Help us test the right conditions for an HCH to AS!This is what Harold was referring to when it comes to blocking one's grill:

This is my wife's car. Mine is done in the same way as I do every winter.
Now, we always use a block heater. Heck, I even use a block heater in the summer months too, albeit with shorter warm up times via the same programmable timer. (Sorry, the temp conversions to F will be left as an exercise)

Now, let me state some observations as to when the AS begins to work:
- If the IAT (air intake temp) is higher that 12C then AS will engage when the cWT (coolant temp) is at 50C.
- If the IAT is lower than 12C then AS will engage when cWT is at 67C.
- The oAT (outside air temp) measured in the dash is not factored directly into the operation of the AS threshold.
- The optimal operating range for the cWT is from 70C to 90C. If hotter than 90C then system is under stress.
- Battery temps are important and they are factored into not just AS but all other IMA related functions (Assist, Regen, etc).
If you have a scangauge or a bluetooth ODB-II logger you can verify much of what I have said though your own observations. By the way, it is pretty hard to spot this info in the Service Manual (paper or DVD) as these thresholds can change with software updates. Since I purchased my 2006 mine have indeed changed twice.
What does this all mean?
- Block heater use helps.
- Plugging your front grille helps even more, especially as the car starts moving.
- Unplug the front grille gradually or completely if the cWT temps start getting too high. The radiator fan will run often and hard. Better yet, get a scangauge to keep an eye on it.
MSantos
msantos: I was hoping you would reply here. At what ambient temperature have you noticed that the engine gets too hot with the blocks in place?
Thanks!
Thanks!
Colby;
I typically install the blocks as soon as the average temps start hovering around 15C (59F) or less. First, I start with the lower intake and avoid plugging the upper ones (to either side of the H).
If the average temps dip below 5C (41F) then I plug all the intake openings. Generally, I also keep an eye on the actual engine temperature via my Scangauge. If the temperature hovers around 90C (194F) (or more) then I remove the upper grille blocks (or even the lower ones if necessary). The last thing we want it to exacerbate the FE by having the radiator fan working like crazy.
I would say that ALL the Grille blocks should come off for ambient temps of 60F or higher.
Cheers;
MSantos
I typically install the blocks as soon as the average temps start hovering around 15C (59F) or less. First, I start with the lower intake and avoid plugging the upper ones (to either side of the H).
If the average temps dip below 5C (41F) then I plug all the intake openings. Generally, I also keep an eye on the actual engine temperature via my Scangauge. If the temperature hovers around 90C (194F) (or more) then I remove the upper grille blocks (or even the lower ones if necessary). The last thing we want it to exacerbate the FE by having the radiator fan working like crazy.
I would say that ALL the Grille blocks should come off for ambient temps of 60F or higher.
Cheers;
MSantos
Okay thanks. I don't think I will put them on, because in the afternoon it's been in the low 60s and I don't want to take them off and put them on everyday.
Thanks a lot! That info really helped.
Thanks a lot! That info really helped.
Yah. Traffic is really bad right now, because they are widening the freeway (or at least trying to, they were supposed to be done in July). So far, they have only made the freeways worse and further congested the side streets. I have gotten pretty good at avoiding peak traffic times and figuring out which way has the least traffic. I don't mind the waiting as much as the significant decrease in FE.
Harold, to post pics from your computer:
At the top of this page in an orange block is a link that says "Share". Click that and it will take you to the photo gallery.
Then click on the HCH section. Once in there look for a link above that says "Upload". You should then be able to browse to your jpegs on your computer and upload them.
Once you are looking at the full-sized picture on this website, right-click on the picture and select properties. On that panel that pops up will be a URL or address. Select and copy that URL (make sure to get all of it as it may be multiple lines).
Then go and post (reply to the thread). Just above the text area to type in are a bunch of icons. The one that looks like a yellow square with mountains is for images. Click on that, a window will pop-up and there you will paste the URL of the picture. Click ok. After you click "Submit Reply" the pic will be in your post.
Thanks to noflash for enlightening me on this how-to and I'm glad to pass it on.
At the top of this page in an orange block is a link that says "Share". Click that and it will take you to the photo gallery.
Then click on the HCH section. Once in there look for a link above that says "Upload". You should then be able to browse to your jpegs on your computer and upload them.
Once you are looking at the full-sized picture on this website, right-click on the picture and select properties. On that panel that pops up will be a URL or address. Select and copy that URL (make sure to get all of it as it may be multiple lines).
Then go and post (reply to the thread). Just above the text area to type in are a bunch of icons. The one that looks like a yellow square with mountains is for images. Click on that, a window will pop-up and there you will paste the URL of the picture. Click ok. After you click "Submit Reply" the pic will be in your post.
Thanks to noflash for enlightening me on this how-to and I'm glad to pass it on.
Chuck:
I too have trouble uploading. It either fails, the page stops responding, or it says that my photos were uploaded but I can't find them. For now I'm just using a separate photo server (google's picasa).
Anyways...
Regarding grill blocking. I had my bumper off today (for unrelated repairs) and I noticed that the left side (facing the front of the car) of the lower grill was blocked by a piece of plastic. It is actually a Honda grill block. I guess they put one in at the factory. On the right side there are screw holes so you can install one (the holes are on the inside of the bumper). If anyone is interested in this, it is called COVER FR BUMPER and the part number is 71105-SNC-A001.
Personally, I would just go for the 50 cent styrofoam tubing, but I thought this would be an interesting addition to the thread.
Below is an image of the inside of the bumper. The right side is blocked.

Sorry. I tried flipping it but it didn't work. Tilt your head.
I too have trouble uploading. It either fails, the page stops responding, or it says that my photos were uploaded but I can't find them. For now I'm just using a separate photo server (google's picasa).
Anyways...
Regarding grill blocking. I had my bumper off today (for unrelated repairs) and I noticed that the left side (facing the front of the car) of the lower grill was blocked by a piece of plastic. It is actually a Honda grill block. I guess they put one in at the factory. On the right side there are screw holes so you can install one (the holes are on the inside of the bumper). If anyone is interested in this, it is called COVER FR BUMPER and the part number is 71105-SNC-A001.
Personally, I would just go for the 50 cent styrofoam tubing, but I thought this would be an interesting addition to the thread.
Below is an image of the inside of the bumper. The right side is blocked.

Sorry. I tried flipping it but it didn't work. Tilt your head.



