Automatic temp spoofer available

Hello. Among first things I noticed owning Prius gen 2 was that if you really want to save fuel you need engine temp spoofer. I was doing fairly fine with switch and resistor but any other member of the family refuse to play around with and I have thought to give the car to my daughter. Therefore I needed better system so I had some made by my friend who knows this stuff. This is full automatic spoofer which goes on at 31 celcius and spoofs to 67-68 c, above that it stops spoofing. Those numbers have been found out by trial and error. Low limit has been 27c without ill effects but I wanted to bit on safer side. Upper limit under 66 keeps engine running for heat and above 70 it goes into S4 instantly wanting idle check which drives me mad. My driving is 99% done (to work, store etc) before engine warms enough for it to want idle check. If engine is above 31c at start it will go straight into S4 without idle check. My fuel consumption is between 4.3 - 4.6 l/100km in summer and if someone lends the car and doesn't use spoofer, consumption can be near 6 l/100km.

While we were at it, we made a bunch of these. Price for unit including postage in old continent is 67€, bit more to US especially if you want in priority post. It comes with 140cm wire and small box with switch if you want to turn it off for running heat. Assembly requires taking off glove box and connecting 3 wires to car's ECU wires. Send me a private message if you like to order one. This is a hobby project and comes without any warranty whatsoever and you have to handle the installation yourself / take your car somewhere where it can be installed.

If you don't know what this thing is, please use search function. Even Google will probably lead you here. All honor to pioneers who first figured this out. I'd say this is the most important single fairly inexpensive gizmo your Prius can have.

 

Oh crap I was hoping for conversation to at least start without some know-it-all starting to shoot his own truths which are easily proven wrong. Do you (Sam) try to boost your ego or what's the thing? Are you the same guy giving me hard time on Facebook? Try to think, just minute or two, how your argument could be possible. I would be keen to know how people can come up with this stuff, really. I really can't figure out what can lead into such conclusion. Hint: fooling sensors doesn't fool laws of thermodynamic.

 

This how this device acts. You should know Prius warm up stages work to understand this. If engine is cold, it starts like it would normally do and go trough warmup stages. Once it reaches +31c the spoofer takes over and raises the engine temp that ECU sees +into 67-68c and that makes car go into S2 which gives you the most benefits of your hybrid system without the need of idle check right away. Now as you drive on and engine temp increases and eventually goes over 68c, the spoofer stops doing anything and ECU sees the correct engine temp. Now as temp goes over 70c, car will go into S3 and wants to do the idle check ceremony, which annoys me above anything other feature on Prius. Once you get it done or shut down & restart, you will go on and eventually end up in S4 which is where you want to be to save fuel.

This is the even better part: When you have driven your car or sun is shining enough for engine temp to be above +31c (or 88F) your car will instantly go into S4 at start and doesn't even need idle check except random check which doesn't happen often at least on my car (2005 French model). Spoofing temp of 68c is high enough that car wont run the engine for heat to cabin heater so you can use only what you have which can be anything between 31-68. This is main reason why spoofer has a switch, you can turn it on and your car will work like it normally does.

I am no expert on pollution stuff and can't argue much about it. If you are hardcore about it, I suggest not to modify anything on your car. Personally, i really cant see how this could make thing much worse as fuel consumption in overall decreases quite a lot. Mine went roughly from 5.5 l/100km to 4.5 l/100km (or 43 mpg to 52 mpg). There is a period once the spoofing starts that engine will run leaner (as coolant temp is spoofed) but engine in good condinition seems to handle it just nice correcting situation with other sensors. My car has about 280000 km's on the odometer and has had long service intervals in the past, like even 18000 km between oil change.

On my everyday driving, it's the short trips that annoy me the most. As Prius warms up catalysator first (S0), then runs the engine mainly to make more heat and uses HV battery for primary energy source if you get moving. This leads into that you either stand still and wait for warm up sequence to stop or go where you are going with electricity = you just warmed the engine and exhaust just to turn the car off again. This ofcourse doesn't matter that much if you have longer trips to drive. Also without spoofer ECU will want to do idle check quite soon as you get moving and where I live there is just about never situation in trafic that it would happen while driving. This leads into that you can drive for a long time with engine running on idle waiting for idle check which is never gets done. It doesn't consume big amount doing so but these little things add up.

Hopefully this clarifies. The thing in this is not spoofing engine to run lean, it's spoofing ECU into more desirable warmup stage. That's what makes the change.

 

Here is a link containing conversation about pollution. Read it for yourself, I didn't want to quote anything as I don't know for sure who is right and who's wrong.

Automatic Coolant Temp Hack for Better MPGs | PriusChat

 

I just went trough this same shit in Facebook and I don't know, people might got scared because of these doomsday oracles. Spoofing has been done for 15 years but it's still not proven method according to them..

As other members of the family are now using the car, I hate to see consumption go up as I know it could be way better. Automatic system is great as now spoofing works without driver noticing anything. I thought to cut the cost and maybe even make few bucks by selling these but now I feel like throwing excess units into trash, nothing is worth of fighting windmills like this. What the **** is wrong with people, if you are a total moron, do you have to be loud too???

 

I'll wait for them to chime in. So far nobody has.

 

As you live in warm country, your engine must usually be over +31c at start so car goes into S4 right away. Then it makes big difference, something around liter / 100km.

Hybrid assistant or such application is very adviceable so you can see warmup stage and get better use of hybrid system. If my engine is cold, I let it run for a while to get over 31c, shut it off and start again so I get S4 without that super annoying idle check.

 

Great news! Remember if you are planning to drive +20 km starting from cold engine to let it run and warm up & re-start and start driving in S4 mode. On shorter trips there is not much difference but it's always adviceable to take it easy when car does first warm up stages. It wastes both gasoline and hv battery..

 

I bet it doesn't. Gen 3 has much better transition to S4 so there is not that much need for this either as in
gen 2.