Its on all the time so just connect any light to 12 volts 
I guess what you really want to know is which wheel is slipping and when right?
I guess what you really want to know is which wheel is slipping and when right?
Four wheel drive indicator light?
Anyone know if there is a way that I can add a "four wheel drive indicator light"? It drive me nuts not knowing when or if four wheel drive is kicked in.
I hade a Chevy Blazer before and always knew if I had it in auto-four wheel,
Manual-four wheel or two wheel.
I hade a Chevy Blazer before and always knew if I had it in auto-four wheel,
Manual-four wheel or two wheel.
1 - 20 of 43 Posts
Yeah. I guess I'm not sure how it works. Are you saying it's on all the time but turns off on any wheel that slips?
"Real Time 4WD sends power to the rear wheels when the primary front-wheel-drive system experiences slippage. The system consists of a power take off (PTO) from the transmission that distributes torque to a propeller shaft that runs to the rear differential. The rear differential contains two internal hydraulic pumps -one driven by the propeller shaft and one driven by the rear wheels - that circulate fluid through an internal multi-plate clutch system. When wheel slippage occurs, the flow rate is greater from the propeller shaft pump and forces the clutches to progressively engage, sending up to 70 percent of the torque to the rear wheels in slick conditions and 30 percent in dry conditions. The system operates automatically and only when needed, requiring no intervention on behalf of the driver to activate. "
4WD: Engagement indicator?
My understanding is that the Honda RT4WD system transmits torque to the rear wheels by tighting up on a clutch pack. This would produce heat build up in the Honda Dual Pump fluid. If the heat build up is too much (such as with a lot of wheel spinning) a thermal cutoff is activated, and the system reverts to 2wd until it cools off.
It might, then, be possible to detect a heat buildup in the torque-control differential case, and infer from that, that torque is being sent to the rear wheels. I think this would require attaching some sort of heat sensor to the case, and recording the temperature in variety of conditions, and then programing a computer to distingish among different causes of temperature change. It would not give an immediate indication, and may not detect short periods of torque transfer. It could also be programmed to identify thermal cutoff.
Anyone got a PDA with remote temperature sensor?
paulj
My understanding is that the Honda RT4WD system transmits torque to the rear wheels by tighting up on a clutch pack. This would produce heat build up in the Honda Dual Pump fluid. If the heat build up is too much (such as with a lot of wheel spinning) a thermal cutoff is activated, and the system reverts to 2wd until it cools off.
It might, then, be possible to detect a heat buildup in the torque-control differential case, and infer from that, that torque is being sent to the rear wheels. I think this would require attaching some sort of heat sensor to the case, and recording the temperature in variety of conditions, and then programing a computer to distingish among different causes of temperature change. It would not give an immediate indication, and may not detect short periods of torque transfer. It could also be programmed to identify thermal cutoff.
Anyone got a PDA with remote temperature sensor?
paulj
I think that'd be too unreliable. I wonder if there are test ports on the unit that can be tapped for *pressure* or clutch location sensing.
-brendan
-brendan
I agree that interpreting the temperature data would be iffy, however I can think of no other way of getting data from the unit without voiding the warnanty. The thermal mass of the casing might be quite large. Quite likely Honda engineers have installed sensors in one or more of these units, but the production model shows no sign of a test port or wiring. I just crawled under my Element and took some pictures.
The case consists of 3 parts.
- The forward bell shaped housing with the propeller shaft entering at the front end,
- a central, roughly cylindrical piece,
- the differential backend, with main mounting bracket.
The drive axles exit through the joint of the back 2 pieces. On the driver's side of the center piece there are two plugs (brass? large inset square socket), probably for draining oil (the bottom one) and refilling. Next to the top plug are the letters DPSF (dual pump .. fluid?).
A closer look at the pictures shows there is a smaller circular structure above the DPSF plug, but I can't tell whether it is removable. It looks more like it is a blind treaded bolt hole.
According to a diagram of the rear-differential assmbly (http://www.quebeccrv.com/other/rtawd.pdf) the clutch pack and oil pumps are all in the smooth forward bell housing. The oil plugs open into the bearing space between the clutch/pump assembly and the differential.
Anyways, I have not read of any port or sensor inside the dual pump unit. Assuming it is as trouble free as the typical differential, Honda has little incentive to provide testing access other than for changing the fluid.
One might also be able to deduce from ABS wheel sensor data when the rear wheels are receiving torque - that is, average the same axle data in the same way the differential would, and compare the two axle averages. Since I don't have ABS I'd have to use some sort of rotation sensor on the properller shaft and the 2 drive shafts
e.g.
average the 2 drive shafts. If this is more than 2.5% different from the propeller shaft and (not brakes and forward rotation), then 4wd is likely.
The clutch pack is activated (at least partially) if the pumping rate of the forward pump is larger than the pumping rate of the rear. The rear is sized 2.5% larger, so the front has to be rotating a bit faster than the rear to pump faster - i.e. the front wheels (as averaged by the differential) have to be spinning some compared to the rear.
paulj
The case consists of 3 parts.
- The forward bell shaped housing with the propeller shaft entering at the front end,
- a central, roughly cylindrical piece,
- the differential backend, with main mounting bracket.
The drive axles exit through the joint of the back 2 pieces. On the driver's side of the center piece there are two plugs (brass? large inset square socket), probably for draining oil (the bottom one) and refilling. Next to the top plug are the letters DPSF (dual pump .. fluid?).
A closer look at the pictures shows there is a smaller circular structure above the DPSF plug, but I can't tell whether it is removable. It looks more like it is a blind treaded bolt hole.
According to a diagram of the rear-differential assmbly (http://www.quebeccrv.com/other/rtawd.pdf) the clutch pack and oil pumps are all in the smooth forward bell housing. The oil plugs open into the bearing space between the clutch/pump assembly and the differential.
Anyways, I have not read of any port or sensor inside the dual pump unit. Assuming it is as trouble free as the typical differential, Honda has little incentive to provide testing access other than for changing the fluid.
One might also be able to deduce from ABS wheel sensor data when the rear wheels are receiving torque - that is, average the same axle data in the same way the differential would, and compare the two axle averages. Since I don't have ABS I'd have to use some sort of rotation sensor on the properller shaft and the 2 drive shafts
e.g.
average the 2 drive shafts. If this is more than 2.5% different from the propeller shaft and (not brakes and forward rotation), then 4wd is likely.
The clutch pack is activated (at least partially) if the pumping rate of the forward pump is larger than the pumping rate of the rear. The rear is sized 2.5% larger, so the front has to be rotating a bit faster than the rear to pump faster - i.e. the front wheels (as averaged by the differential) have to be spinning some compared to the rear.
paulj
As a matter of curiosity I estimated what the speed difference would be if one tire was the temporary spare.
The Wrangler HP has a diameter of 27.7" (tirerack data)
145/90/16 spare is 26.3"
94.86% of regular tire
If the differential does a simple average, the axle with the spare spins 1/.974 = 1.027 times faster than the axle with 2 regular tires. This is right on the border line of triggering the 4wd - at least until the thermal cutoff is triggered. I wonder if it is better to put the temporary spare on the rear axle if possible? The manual doesn't mention anything like that. This of course, does not take into account wear of the front tires, different tire pressures, and spring pressure in the clutch pack. Also with a slight speed difference, the clutch pack may engage only lightly, sending a small amount of torque to the rear.
paulj
The Wrangler HP has a diameter of 27.7" (tirerack data)
145/90/16 spare is 26.3"
94.86% of regular tire
If the differential does a simple average, the axle with the spare spins 1/.974 = 1.027 times faster than the axle with 2 regular tires. This is right on the border line of triggering the 4wd - at least until the thermal cutoff is triggered. I wonder if it is better to put the temporary spare on the rear axle if possible? The manual doesn't mention anything like that. This of course, does not take into account wear of the front tires, different tire pressures, and spring pressure in the clutch pack. Also with a slight speed difference, the clutch pack may engage only lightly, sending a small amount of torque to the rear.
paulj
DPSF = "Dual Pump System" or DPS Fluid.
Googled DPSF, saw a reference to DPS4WD on a japanese page:
http://www.hondanet.co.jp/verno-yamato/html/060_m_oil.html
...then googled DPS Honda. It appears that DPS is the name of the AWD system in Japan.
An aside: speaking of Japan, what's this???
http://www.purehonda.com/cool/japanonly/jwjinfo.html
Ok, I'll take a look at the service manual, but I suppose I'll find the same info as you did: no way to peek inside the unit...
-brendan
Googled DPSF, saw a reference to DPS4WD on a japanese page:
http://www.hondanet.co.jp/verno-yamato/html/060_m_oil.html
...then googled DPS Honda.
It appears that DPS is the name of the AWD system in Japan.An aside: speaking of Japan, what's this???
http://www.purehonda.com/cool/japanonly/jwjinfo.html
Ok, I'll take a look at the service manual, but I suppose I'll find the same info as you did: no way to peek inside the unit...
-brendan
There was a recent thread on one of the crv boards about this problem: they put the wrong tire on (same brand/line/size, but the manufacturer made them differently for 3 vehicles) and their AWD was always engaging. Ick.
With wear it's likely that the standard tires will be slightly smaller, bringing the ratios to within the 2.5% tolerance, right?
-brendan
With wear it's likely that the standard tires will be slightly smaller, bringing the ratios to within the 2.5% tolerance, right?
-brendan
Re: 4wd Light idea...
i'm sure that someone (paulj?) knows for sure, but i'm pretty sure that there is no electrical circuit for the awd, its purely mechanical.
so there is nothing to 'tap into'
i'm sure that someone (paulj?) knows for sure, but i'm pretty sure that there is no electrical circuit for the awd, its purely mechanical.
so there is nothing to 'tap into'
Re: 4wd Light idea...
yeah u would probally need to make ur own
yeah u would probally need to make ur own
Re: 4wd Light idea...
Why does everyone have such a hard-on for a light that shows when the AWD is engaged? Give it a rest, that crap is for ancient 4WD trucks. I'm certain if Honda felt that you needed to know when AWD was engaged, they would have put a light there.
Thats the problem with society, everyone wants light up crap...windshield washer nozzles, cell phone batteries/antennas and so forth. Idiot lights are called so for a reason.
Why does everyone have such a hard-on for a light that shows when the AWD is engaged? Give it a rest, that crap is for ancient 4WD trucks. I'm certain if Honda felt that you needed to know when AWD was engaged, they would have put a light there.
Thats the problem with society, everyone wants light up crap...windshield washer nozzles, cell phone batteries/antennas and so forth. Idiot lights are called so for a reason.
Re: 4wd Light idea...
I little light would be neat but I'd rather have a siren, a really LOUD one and an oxygen mask to fall from the overhead bin, oh, and auto-inflate pontoons, oh yeah, and something that goes, "PING!"
I little light would be neat but I'd rather have a siren, a really LOUD one and an oxygen mask to fall from the overhead bin, oh, and auto-inflate pontoons, oh yeah, and something that goes, "PING!"
Re: 4wd Light idea...
also you would know if your awd id malfunctioning. Or if its on too long.... stuff like that :evil:
It would be a neat mod! i meen comeon... whats cooler than a light that comes on when you spin the wheelsGenom said:Why does everyone have such a hard-on for a light that shows when the AWD is engaged? Give it a rest, that crap is for ancient 4WD trucks. I'm certain if Honda felt that you needed to know when AWD was engaged, they would have put a light there.
Thats the problem with society, everyone wants light up crap...windshield washer nozzles, cell phone batteries/antennas and so forth. Idiot lights are called so for a reason.
also you would know if your awd id malfunctioning. Or if its on too long.... stuff like that :evil:
Re: 4wd Light idea...
Yeah, its a neat idea until someone is on a snowy or icy road and the AWD engages and disengages frantically, flashing a light and causing someone to have an epileptic siezure and crash.
I generally like my vehicles to have nothing more than it needs to go and stop, all the rest is BS.
Thats also why I believe most people drive like retards...the car does all the work nowadays, there's almost no real driving skill involved. I used to do alot of racing at the local oval track years ago, so I consider myself to be a highly skilled driver. ( whoops, got a little off topic there )
Yeah, its a neat idea until someone is on a snowy or icy road and the AWD engages and disengages frantically, flashing a light and causing someone to have an epileptic siezure and crash.
I generally like my vehicles to have nothing more than it needs to go and stop, all the rest is BS.
Thats also why I believe most people drive like retards...the car does all the work nowadays, there's almost no real driving skill involved. I used to do alot of racing at the local oval track years ago, so I consider myself to be a highly skilled driver. ( whoops, got a little off topic there )
Re: 4wd Light idea...
and the do not cross blinkking hands are the same too. so to summ it all up, if u have seasures from videogames, lights or etc,,, dont drive
well when red lights are out they blink tooGenom said:Yeah, its a neat idea until someone is on a snowy or icy road and the AWD engages and disengages frantically, flashing a light and causing someone to have an epileptic siezure and crash.
I generally like my vehicles to have nothing more than it needs to go and stop, all the rest is BS.
Thats also why I believe most people drive like retards...the car does all the work nowadays, there's almost no real driving skill involved. I used to do alot of racing at the local oval track years ago, so I consider myself to be a highly skilled driver. ( whoops, got a little off topic there )
and the do not cross blinkking hands are the same too. so to summ it all up, if u have seasures from videogames, lights or etc,,, dont drive
Re: 4wd Light idea...
Could you define 'engaged'? What would be the criteria?
Take a look at the graph on page 6 of the QuebecCRV document (should be a link in the off-road section). There is a nice pair of graphs, showing relative torque being sent to front and rear axles during a slippery start. In a second and half, the amount of torque sent to the rear wheels rises rapidly to 70% then tapers off to 30%. I suspect these graphs are based on a heavily instrument test unit, not a production one.
What I'd suggest doing is study up on the ABS system, and figure out a way of tapping into its data about the spin rate of the 4 wheels. With some clever programming you should be to simulate the action of the rt4wd unit, a from that generate a display indicating 'engagement'.
paulj
Could you define 'engaged'? What would be the criteria?
Take a look at the graph on page 6 of the QuebecCRV document (should be a link in the off-road section). There is a nice pair of graphs, showing relative torque being sent to front and rear axles during a slippery start. In a second and half, the amount of torque sent to the rear wheels rises rapidly to 70% then tapers off to 30%. I suspect these graphs are based on a heavily instrument test unit, not a production one.
What I'd suggest doing is study up on the ABS system, and figure out a way of tapping into its data about the spin rate of the 4 wheels. With some clever programming you should be to simulate the action of the rt4wd unit, a from that generate a display indicating 'engagement'.
paulj
Re: 4wd Light idea...
thanks paulJ i have been directed away from this.... im not too good a wiring at all! oh well, it was a thought
thanks paulJ i have been directed away from this
.... im not too good a wiring at all! oh well, it was a thought
Re: 4wd Light idea...
I think we need a gage or maybe a really detailed backlit LCD graph since its not just off or on AWD. Something that could really take ALL your attention away from watching THE ROAD, which of course there is really no reason to be using your FULL attention on the road if the AWD is coming on.....
Gotta save your focus for PRIORITIES...like drinking your starbucks WHILE dialing your cell phone and watching the incoming pics on your cell phone, and punching in the sat station, while driving down that icey road....
I think we need a gage or maybe a really detailed backlit LCD graph since its not just off or on AWD. Something that could really take ALL your attention away from watching THE ROAD, which of course there is really no reason to be using your FULL attention on the road if the AWD is coming on.....
Gotta save your focus for PRIORITIES...like drinking your starbucks WHILE dialing your cell phone and watching the incoming pics on your cell phone, and punching in the sat station, while driving down that icey road....
1 - 20 of 43 Posts
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