Anyone pulled their power steering fuse?

[detroiter]

Has anyone pulled their powering steering fuse? And if so, what's
your opinion on it?

I decided to try going without mine for a while today and honestly,
aside from the much heavier steering feel, the car feels multiple
times better in my opinion. It seems much more planted and it doesn't
have the left or right wandering that's so typical. I might just end up
leaving the fuse out and call it a day, the driving feedback seems
much better without it than with it.

[DMZ]

Has anyone pulled their powering steering fuse? And if so, what's
your opinion on it?

I decided to try going without mine for a while today and honestly,
aside from the much heavier steering feel, the car feels multiple
times better in my opinion. It seems much more planted and it doesn't
have the left or right wandering that's so typical. I might just end up
leaving the fuse out and call it a day, the driving feedback seems
much better without it than with it.

I have. Heavy steering at lower speeds, but it is quite nice on the highway. I let go of the wheel on a long straight stretch and must have went about a mile before the car began to drift a bit. I put the fuse back in because I really like the EPS around town. If I was to take a long trip I might pull it back out. It is nice that such a mod is so easy, and there is no cost.

[cali yaris]

I've had that disabled for a long time now -- I like it. Most people don't like it.

Even better is to also remove the servo motor from the steering column; I plan to get to that pretty soon.

[detroiter]

Is their any possibility of hurting anything by driving without the p/s fuse plugged in?

[CTScott]

Is their any possibility of hurting anything by driving without the p/s fuse plugged in?

You won't hurt anything having it pulled.

I have done some experimentation with fooling the P/S ECU and will eventually have a product to offer which allow configurable disabling of the EPS. Where, you'll be able to select options like having it on-proportional or on-full at low speed (<5, <10, or <25 MPH) and off completely at speeds above the configured threshold.

[Shinare]

You won't hurt anything having it pulled.

I have done some experimentation with fooling the P/S ECU and will eventually have a product to offer which allow configurable disabling of the EPS. Where, you'll be able to select options like having it on-proportional or on-full at low speed (<5, <10, or <25 MPH) and off completely at speeds above the configured threshold.

That sounds WAY COOL.

[marcus]

subscribed..this is interesting..but wouldnt this just gets rid of loose steering on low speed under 20km/hr higher should still be the same wouldnt it.

now where would this fuse be.. maybe i can rewire it to make a switch for it..

[DMZ]

You won't hurt anything having it pulled.

I have done some experimentation with fooling the P/S ECU and will eventually have a product to offer which allow configurable disabling of the EPS. Where, you'll be able to select options like having it on-proportional or on-full at low speed (<5, <10, or <25 MPH) and off completely at speeds above the configured threshold.

If it is plug and go. I'm in.

[CTScott]

subscribed..this is interesting..but wouldnt this just gets rid of loose steering on low speed under 20km/hr higher should still be the same wouldnt it.

now where would this fuse be.. maybe i can rewire it to make a switch for it..

At higher speeds the EPS is still proportional, which is what causes the wander and inconsistent feel. At low speed with no assist it can be pretty hard to steer. My idea is to flatten the response on both ends so that it feels the same through the whole range.


The fuse is under the hood, but you could do the switching on the large power wire to the EPS ECU.

[marcus]

cool.. got to try this..thanks

[detroiter]

I've driven around a bit more today without the fuse and the wander is definitely gone from what you'd normally expect with the electric powersteering running in place.

Now does the electric powersteering compensate to each of the front wheels? Like for example, god knows this car has no torque but sometimes if you nail the gas at a lower speed and the car really takes off, sometimes it has the reponse that your car is "pulling" to the left or the right until the torque lets up a bit.

Since pulling out the fuse, when nailing the gas hard, the car pulls straight as an arrow with now feeling whatsoever that it's trying to put power seperately to the left or right wheel.

[CTScott]

I've driven around a bit more today without the fuse and the wander is definitely gone from what you'd normally expect with the electric powersteering running in place.

Now does the electric powersteering compensate to each of the front wheels? Like for example, god knows this car has no torque but sometimes if you nail the gas at a lower speed and the car really takes off, sometimes it has the reponse that your car is "pulling" to the left or the right until the torque lets up a bit.

Since pulling out the fuse, when nailing the gas hard, the car pulls straight as an arrow with now feeling whatsoever that it's trying to put power seperately to the left or right wheel.

There's a torque sensor on the steering column. The problem is that it can't tell the difference between torque applied by the driver or by the road.

[enviri]

is there any other difference? its not like on older cars where pulling the belt will give it more power, i know. Maybe just more stability in voltage or something lol

[CTScott]

is there any other difference? its not like on older cars where pulling the belt will give it more power, i know. Maybe just more stability in voltage or something lol

The main idea behind EPS is not wasting power/fuel, driving a pump when it is not needed, so it is actually pretty efficient. When you are steering like crazy at low speed, is when the EPS motor draws the most current, so that is where you'd notice the biggest power gain from eliminating that load.

[marcus]

getting more interesting..

[marcus]

OK i tried taking the fuse on etcs 10 amps but the car wont stay on itll crank but it drops the rev to zero.. does battery have to be unplug too.

[DMZ]

OK i tried taking the fuse on etcs 10 amps but the car wont stay on itll crank but it drops the rev to zero.. does battery have to be unplug too.

It is a red 50 amp fuse labeled EPS. You do not have to disconnect the battery to pull it out.

[marcus]

It is a red 50 amp fuse labeled EPS. You do not have to disconnect the battery to pull it out.

oh maybe i took out the wrong one thought its the etcs.. now i need to find eps..thanks

what does s-lock stands for its missing a fuse in it..

[DMZ]

oh maybe i took out the wrong one thought its the etcs.. now i need to find eps..thanks

what does s-lock stands for its missing a fuse in it..

Look in the fuse box on the drivers side. The EPS fuse is between the ABS and HTR fuses. It is a big, square fuse.

I am not sure what the s-lock is for.

[CTScott]

oh maybe i took out the wrong one thought its the etcs.. now i need to find eps..thanks

what does s-lock stands for its missing a fuse in it..

ETCS is one of the ECM's fuses. S-LOCK is for the AT shift lock. If you have a MT it will be empty.

[marcus]

thanks ctscott.. that s-lock it bothering me..

anyways i did try taking the fuse off eps..and wow steering is super stiff last time i drove a car like that was an old chevy 85 with no power steering feels good on straight away but annoying on turns..

[enviri]

yeah no kidding on the super stiff wheel. i have an 85 jetta w/o p/s and the jetta was a little easier to drive. lol.

I test drove w/o p/s and man i have to relearn the car again. doesnt help that now i notice on the highway bumps, (CT has TERRIBLE random bumps) i find myself in fighting the wheel alot on turns, and sometimes it feels im temporarily airborne, hah. good stuff!

[DMZ]

yeah no kidding on the super stiff wheel. i have an 85 jetta w/o p/s and the jetta was a little easier to drive. lol.

I test drove w/o p/s and man i have to relearn the car again. doesnt help that now i notice on the highway bumps, (CT has TERRIBLE random bumps) i find myself in fighting the wheel alot on turns, and sometimes it feels im temporarily airborne, hah. good stuff!

Ha. Now you know why pre-PS auto had those huge steering wheels and after market suicide knobs.

[marcus]

i just put my summer tires on and that alone made the steering a little stiffer than stock rims..now with eps off i dont think i even wanna try it..lol

[detroiter]

Honestly I've noticed that driving over bumps feels much less harsh than when driving with the p/s fuse in place. Maybe it's the p/s giving feedback through the wheel but when driving today over a few bumps that always make me grimace in pain usually, I went right over them with out even barely feeling them. Does the p/s exaggerate road feedback?

[SKurj]

Hey this is cool, glad someone tried this. My 04 echo hb has no power or electrical assist steering and I prefer it on the highway. Guess I will be pulling the fuse and seeing how the 09 works.

[Bluevitz-rs]

I wish I had ESP :frown:

My belt blew off my PS pump in the middle of winter, so I had no choice but to drive it that way for a few weeks. I then decided that the car feels SO much better without hydraulic assist. At the limits you can feel the front tires breaking loose as the steering feel starts to get lighter. Not to mention you can feel every crack in the road mid corner now too.

The only bitch is when you're trying to get in and out of parking spots.

[marcus]

curious if we i make a switch for this can i actually turn this on and off while driving??? anyone? any negative effects like damaging the EPS??

[SKurj]

curious if we i make a switch for this can i actually turn this on and off while driving??? anyone? any negative effects like damaging the EPS??

Now that would be cool..

[BLH]

You would have to use a heavy wire and switch or power relay.
The fuse is a fifty amp one.

[bB2NER]

A relay would work fine with a switch to activate it maybe?
I tried pulling the fuse and found the steering to be quite heavy because of the small wheel.

[marcus]

im dont get why i would need a relay if im just bypassing a wire and adding a switch in between...

[marcus]

Ok got It I got extra relay from hid kits still worried about damaging the eps for adding a switch .....

[bB2NER]

im dont get why i would need a relay if im just bypassing a wire and adding a switch in between...

You could always try and find a switch that is rated for 50 amps of higher then. That might be expensive tho.

[auxmike]

I've no plans to mess with mine. I'm pleased with the power steering.

[bB2NER]

Just got back from a 1400 mile road trip. Compared to my xB/bB with regular PS, the Yaris steering is way too touchy. It feels like you are disconnected IMHO.

[Zebra]

Curiosity got the best of me today so I pried the 50 amp fuse out of the fuse panel and gave manual steering (aka: armstrong steering) a try. I have to admit that I was impressed with the improved handling on the highway. Keeping the Yaris going straight is full-time job with the EPS, it's much better without.

BUT...... Under 30mph it was just way too much work and in my opinion, somewhat unsafe. Manual steering in just about any other car needs less effort and yes the steering wheel is too small for manual steering. Still, it would take more than a big steering wheel to make it tolerable on a daily basis.

Having a system to attenuate the EPS at higher speeds might be the answer. I really like the effect on the highway but that's where it ends..

[marcus]

zebra: now you know why im planning a switch option..but worried about turning this on and off while driving...

[Zebra]

zebra: now you know why im planning a switch option..but worried about turning this on and off while driving...

Why are you worried? Worried that a power spike would damage the EPS? Worried someone else will trip the switch and have an accident? Worried that your wiring job won't work at a critical time? Worried that an accident could result in a lawsuit for negligence?

I wouldn't worry about the power spike....

[toy_toronto]

You won't hurt anything having it pulled.

I have done some experimentation with fooling the P/S ECU and will eventually have a product to offer which allow configurable disabling of the EPS. Where, you'll be able to select options like having it on-proportional or on-full at low speed (<5, <10, or <25 MPH) and off completely at speeds above the configured threshold.

CTScott, i would pay someone to have this option :wink:

-toy

[rningonfumes]

I like this thread!

Marcus and CTScott.

What is the unit that adjust to speed levels...ie more power when you're not moving vs less when you're at speed? Is there any way to just affect that unit? Like telling it to give no power at all after a certain speed?

As for the switch, where in the line would you put it, between the unit and the fuse or do it in the fuse box?

Lastly...CT...I know you have ideas! Where are you at on this subject?

[Bluevitz-rs]

There's a torque sensor built into the steering column that senses how much force is being applied to turn the wheels and adds more or less power to the motor to assist.

I dont know if CT has experimented with adding resistance to the output ifthe sensor to tell the system not to add as much power.

[CTScott]

From what I have found in my experimentation, fooling the PS ECU in regards to vehicle speed is not enough. I actually have to also override the torque sensor data. The "highway wander" is a good example of why this is necessary. Even at high speeds, there is enough power assist that small changes in the torque sensor feedback result in steering adjustment.

One of the simplest implementations may be to add a DPDT relay in line with the power steering motor leads, and control the relay based on vehicle speed.

[CrankyOldMan]

If you want to just add an on/off switch that won't mess with the existing wire harness you could get an external fuse holder, 50A relay and a toggle switch. The toggle switch would be connected to the battery or accessory line and the coil of the relay, and the switch of the relay would enable/disable the power steering fuse. I'm assuming that the power steering is still 12V, so pretty much any automotive relay with 50A contact rating would work. The toggle switch can be anything that can handle 12-14V and whatever the coil current of the relay is. You would have to pull a pair of wires through the firewall, but that shouldn't be too hard either.

http://img585.imageshack.us/img585/6191/disableswitch.png

[CrankyOldMan]

One of the simplest implementations may be to add a DPDT relay in line with the power steering motor leads, and control the relay based on vehicle speed.

Is this something that could be based on the "vehicle speed" wire on the radio harness? I've only got a basic electronics knowledge at the moment, but I'm sure there's an IC that can read the pulses from this line.

[CTScott]

Is this something that could be based on the "vehicle speed" wire on the radio harness? I've only got a basic electronics knowledge at the moment, but I'm sure there's an IC that can read the pulses from this line.

If you wanted to do it without a microcontroller, you could use a frequency to voltage converter IC and then feed that through a comparator.

[CrankyOldMan]

If you wanted to do it without a microcontroller, you could use a frequency to voltage converter IC and then feed that through a comparator.

I've located some potential parts for these, but I'm not sure how I'd go about measuring the pulse per mph. Do you by chance already know what it is?

I'm also guessing that the signal is 12V, so you'd have to use a regulator or voltage divider to get down to the 5V input that the F/V chip is expecting. I'm still looking through the datasheet to see exactly how the F/V converter works. Any suggestions on what kind of comparator would be the right type to use?

[CTScott]

I've located some potential parts for these, but I'm not sure how I'd go about measuring the pulse per mph. Do you by chance already know what it is?

I'm also guessing that the signal is 12V, so you'd have to use a regulator or voltage divider to get down to the 5V input that the F/V chip is expecting. I'm still looking through the datasheet to see exactly how the F/V converter works. Any suggestions on what kind of comparator would be the right type to use?

The VSS signal is actually a 5V signal. If memory serves me correct the frequency is 100 Hz at 40 MPH and about 20 Hz at 10 MPH.

For the comparator, a general purpose one, like the LT1011 would be fine. It is amazing how much more complicated this gets trying to do it with analog, rather than digital. I should just build you up one to experiment with using a microcontroller. I could make a simple little black box that connects to ignition switched power and then has an output to drive the relay coil. I could have a pot on the box to adjust the switch over speed.

[CrankyOldMan]

It is amazing how much more complicated this gets trying to do it with analog, rather than digital.

Why would this be the case? There are a few additional passive components that need to be added around the F/V and comparator, but it seems to be fairly straightforward. Is it a matter of getting a comparator that has enough hysteresis to prevent noise around the switching point from making the output fluctuate? Sorry if those aren't the right terms, I just looked some of this up.

I looked at the EWD and the power steering is already throttled by the ECU based on speed and the torque sensor. According to p 176 of the EWD:
* In order to reduce driver’s steering force, the assist current is calculated from the torque sensor signal and vehicle speed
signal of the meter or CAN communication to output to the motor.

∗ When abnormality occurs in the system, the assist is prohibited by shutting off the power source relay and motor relay in
ECU, and the warning light (P/S) in the meter is lit up.

So if we were to ever crack the ECU, we could in theory change the control algorithm. It seems strange that removing the fuse doesn't turn on the (P/S) light.

[Jason@SportsCar]

I like elec power steering. It rocked in my RX-8, made it one of the most pleasurable cars to autox - past cars I raced with traditional systems always struggled to keep up, our Corvette use to puke power steering parts regularly. :mad:

I think the system in the Yaris works great. In the GT/B-Spec cars it works seamlessly, I had no problem on the track with it.

I hated the H Prod car when we first started racing it... Due to some hacked wiring the system never worked, and with a 10" wide slick the car was a beast, always fighting you in the turns. However, with time we were able to work out some of the steering bind, making it easier to drive. Ditching the elec motor and the stock column made it much easier to turn (still not as good as the EPS system), and it actually dropped a good bit of weight.

No brainier for me, in a street car I would keep it.

[CTScott]

I like elec power steering. It rocked in my RX-8, made it one of the most pleasurable cars to autox - past cars I raced with traditional systems always struggled to keep up, our Corvette use to puke power steering parts regularly. :mad:

I think the system in the Yaris works great. In the GT/B-Spec cars it works seamlessly, I had no problem on the track with it.

I hated the H Prod car when we first started racing it... Due to some hacked wiring the system never worked, and with a 10" wide slick the car was a beast, always fighting you in the turns. However, with time we were able to work out some of the steering bind, making it easier to drive. Ditching the elec motor and the stock column made it much easier to turn (still not as good as the EPS system), and it actually dropped a good bit of weight.

No brainier for me, in a street car I would keep it.



It actually sounds like it is better for track than street. The primary complaint about the EPS is how it induces wander at highway speed.

[CTScott]

Why would this be the case? There are a few additional passive components that need to be added around the F/V and comparator, but it seems to be fairly straightforward. Is it a matter of getting a comparator that has enough hysteresis to prevent noise around the switching point from making the output fluctuate? Sorry if those aren't the right terms, I just looked some of this up.

I looked at the EWD and the power steering is already throttled by the ECU based on speed and the torque sensor. According to p 176 of the EWD:


So if we were to ever crack the ECU, we could in theory change the control algorithm. It seems strange that removing the fuse doesn't turn on the (P/S) light.


I just mean based on the overall number of components and the little bit of math required for configuring the comparator, etc.

The P/S light id turned on by the combination meter when the EPS reports an issue. If the EPS isn't alive it can't complain.

[CrankyOldMan]

I just mean based on the overall number of components and the little bit of math required for configuring the comparator, etc.

Understood. For an entry level EE student like me, the more cost effective solution would be using components and a breadboard instead of a PLD. Most of us DIY-ers don't have access to a programmer. The only microcontroller I've been exposed to so far comes on a $150 dev board, and that's a bit too expensive to cloister in a box under the dash. =)

[rningonfumes]

...it's like watching soft core.

Keep going!

[CrankyOldMan]

The VSS signal is actually a 5V signal. If memory serves me correct the frequency is 100 Hz at 40 MPH and about 20 Hz at 10 MPH.

Is the pulse width fixed, or is it always 50% duty cycle? I'm trying to do a PSPICE sim of the F/V converter and need some idea of the settings for the VPULSE component.

[CTScott]

Is the pulse width fixed, or is it always 50% duty cycle? I'm trying to do a PSPICE sim of the F/V converter and need some idea of the settings for the VPULSE component.

It's a 50% duty cycle signal, where the width of the pulse decreases as speed increases. If you need a definite frequency value at a particular speed, let me know, as I have a portable scope.

[CrankyOldMan]

It's a 50% duty cycle signal, where the width of the pulse decreases as speed increases.

That should be good enough for the sim, just have to figure out how to do a frequency sweep on a VPULSE. Thanks!