G27 Gas & Brake problem

  • Thread starter Thread starter Joe Ferreira
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Joe Ferreira

Joe Ferreira

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76
South Africa
Cape Town
Gas & brake problem
On gt5 Academy edition on PS3 with G27 setup. When I brake to a standstill with X1010 or any car for that matter, the revs drop down to idling as it should but if I keep my foot on the brake pedal the revs shoots up into the red without touching the gas pedal. The brake also comes on at random while driving, only slightly but more than enough to stuff a race completly. A good flick of the brake pedal will fix it for a few seconds before it starts again. I have flushed out the pots time and again, so it can't be dirty pots. There must be a current leakage between these two pedals somehow and somewhere. The pedals are no longer in their original plastic casing as I have removed them and inverted them and fixed them to a metal plate bolted to the rig. Is it possible that the pedals being screwed on to a common plate will cause this type of interaction between the pedals. I did not insulate the pedal frames from the plate. The wires are also well clear of the plate. I've also tried a earlier GT5 edition with the same result, so it's not a software bug. Does anybody have some possible answers. I'll try anything.
 
When did you start having the issue? Did it just pop up or did it start after you inverted? I'm not sure about the plate being the issue, as the pedals all use a common grounding wire anyway. But to test, you could remove the pedals from the plate and then run a practice race and see if your issue continues. If so, then you can rule out the plate, if so, get some rubber mat to place in between the plate and pedal bracket.

Right, what to do if not. Can't forget the step after the if not. If you don't have a multimeter, ohmmeter, volt meter, whatever wish to call it. You will need one, or a couple of wires and a flashlight bulb and battery. What you want to check for is continuity. Both the one you want, and dont want. Search for a G27 pin out diagram, easy to find using google, then make sure first that every wire is getting continuity with very little resistance. On a multimeter there will be a little speaker that you turn the selector to. On the flashlight, the light will light up. So what you want to do is place the ground(black) probe in one pin, then touch it to the metal connect at each wire by the pots. only one should get the speaker to make noise, except ground and the red (+) power feed wires, which should get all three of the either wires to beep. if you get any noise from either of the other three wires (orange, white, green) from more then one pin, then your wires are done for. if not, then you should be able to check the resistance of the pots and see if anything weird is happening with a multimeter, if those are good than it would only leave the PCB in the wheel.

Sorry if that is long winded or hard to read, its still to early and I haven't had my first cup of coffee yet.
 
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Hi there Rallywagon,
Thanks for the input, I will ask a friend of mine to check out what you suggested as he has all the gear one needs. I will post all tests done and any positive outcome in case someone else might have the same problem. Thanks again!
Regards
Joe
 
Good evening Joe! New pots are very hard to find. I've had the same problem with the G25 and G27. Try and locate some electrical contact cleaner. Here in the states I use a product called CRC QD Electronic Cleaner. It comes in a 312g spray can. There is a small opening on the side of the pot, spray the cleaner inside this opening while pumping the pedal. This will eliminate any issues with brake drag! :cheers:
 
Rallywagon
@Joe Ferreira, so whats the verdict lad, did you get it figured out?
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Not yet, my pedals are located in a footwell, very dufficult to reach, wires only about 100mm long. Could not test properly. Have purchased two new 10K pots that looks like they may fit. I am just going to disconnect the brake pot & connect the new pot. If the brake spiking persists then at least I know the fault was not caused by the brake pot. If on the other hand the spiking no longer appears then the fault lies with the pot in which case I will fit the new pot to the brake pedal. I'm not even sure of the values of the pots vary with the pedals or if they are all the same.
 
Joe Ferreira
Not yet, my pedals are located in a footwell, very dufficult to reach, wires only about 100mm long. Could not test properly. Have purchased two new 10K pots that looks like they may fit. I am just going to disconnect the brake pot & connect the new pot. If the brake spiking persists then at least I know the fault was not caused by the brake pot. If on the other hand the spiking no longer appears then the fault lies with the pot in which case I will fit the new pot to the brake pedal. I'm not even sure of the values of the pots vary with the pedals or if they are all the same.
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It won't matter I don't think, the game reads the low and high values when you first press and depress your pedal. So long as the values can fully be read, then it shouldn't be an issue.
 
Has anyone checked if the pot values are the same on all three pedals? I have a spare G27 pedal I'm not
Bluntified
Here's some useful specs of the G27/25 pots.

http://insidesimracing.tv/forums/topic/3150-looking-for-a-pot-dealer-in-the-us/
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I have now checked all 3 pots and all are 10k. I have also stripped the G27 pot and the new 10k pot that I bought for R20.00 ($2.00 ea). Same or very similar construction but the new pot seem a better quality and rotating it by hand it feels a lot smoother. I have not fitted it yet as I will have to modify the shaft. I connected it and drove with it connected without experiencling spikes. When I operated the brake pot by hand I can create a spike on the brake by the very smallest of rotation maybe only one or two degrees. I've noticed that there is hardly any movement required of the sweeper within the pot between no brake & slight brake, slight brake being the spike. By the way my pot was absolutly spotless inside so it was not carbon dust or anything of that nature that is causing the spiking. The travel of the sweeper component of the pot to absolute zero is detirmed by the limiter built into the sweeper coming up against the stop that is notched inward on pot's casing. If one cuts away a very small bit of the plastic on the sweeper's lower limiter (zero limit) the sweeper will then be able to rotate fractionally below the absolute zero position ie: in a negative position so to speak, it should and will have the effect of requiring a slightly more rotational travel of the sweeper on braking before actual braking comes into effect. By braking hard we are only using about 20% of the the pot and you can imagine how small a part is being used for feathering the brake, it is hardly noticeable. Your car's brake does not operate by merely resting your foot on the brake pedal. So too should there be some movement on the brake pedal of a sim car. In the case of the G27 there is no play to speak of and I thing that this may well be giving us all this spiking problem. In additioin to above opinion lets look at the brake pedal itself. The brake pedal also has a release travel limit which is located and is the part of pedal the holds the foot pad. The pedal movement limit on brake release is when these two projections bottoms on to the U shaped bracket. The rotational travel of the pot's sweeper to zero on release of the brake is also detirmined by this pedal limit. Imagine if one put a spacer between the pedal stop and the bracket, the effect would be that you would not be able to completely release the brake. So, by the same token if one ground away a wee bit of the metal stop the brake pedal will be able to travel slightly higher on release' you would not even notice it, but the net effect would be to produce via spring & through the meshed gears a greater rotational force on the pot's shaft towards zero and even slightly past and away from braking. One or both of these options must surly eliminate spiking. It's not dirt and that you can take to the bank. I'm sorry for being so long winded but could not express myself any shorter. I would like to hear from interested parties if they agree or disagree or have another opinion. Unless you have opened a pot and stripped down a pedal assembly at some stage it may be a bit difficult to cast an opinion. Positive & negative responses welcome.
 
I'm sorry, I can't check. When I got mine replaced, the guy who did it stripped a screw on the gas pedal and can't get it out.

Have you tried spraying some contact cleaner on your pots?

I'm sorry I can't give anymore help on this, it's a little out of my league. I have a buddy of mine that I work with that does this type of thing for me, I can ask him what he thinks when I see him at work tomorrow night.

PS: Stripping down pots is very difficult and risky, that's why I recommend buying one online and just put it in.
 
Ok, I'll bite, and go for a sorta-quasi-disagreement, I think. when you where testing the pots for limits, did you recalibrate the wheel (unplug the usb cable and plug it back it) while testing? When you very first plug in the wheel, the wheel itself will spin lock to lock to "learn" center. Since there are no motors in the pedals to do this, it is done manually when you press a pedal. To understand what I mean, get on track during a in your lobby/free run/what have you, unplug/plug back in your wheel, then press your pedal, you will see that almost instantly on the first press, it will spike, and hold the spike all the way until the pedal is fully pressed. This is how the wheel "learns" the distance fully released to fully pressed pedals.
With that in mind, I'll address this: "Your car's brake does not operate by merely resting your foot on the brake pedal. So too should there be some movement on the brake pedal of a sim car. In the case of the G27 there is no play to speak of and I thing that this may well be giving us all this spiking problem. In additioin to above opinion lets look at the brake pedal itself."
This is set in game, not by the wheel itself. Typically in a sim racer, this is actually an adjustable variable, in both the wheel, and all of the pedals. Its called deadzone, however, it is a static setting in GT5.

Edit:
Something else to add. I have also found while changing around springs one day (have my pedals inverted) I did it while in a lobby. Swapped springs, and went to drive again, and found that my pedal was holding a slight accel while the pedal was fully released. I figure that was cased by the pedal actually taking the pot back, past the initially set zero when swapping the spring. Once the new spring was in and bolted up, the new set zero was set a bit behind the proper zero, and so it caused the accel to act as if it where depressed slightly.
 
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Rallywagon
Ok, I'll bite, and go for a sorta-quasi-disagreement, I think. when you where testing the pots for limits, did you recalibrate the wheel (unplug the usb cable and plug it back it) while testing? When you very first plug in the wheel, the wheel itself will spin lock to lock to "learn" center. Since there are no motors in the pedals to do this, it is done manually when you press a pedal. To understand what I mean, get on track during a in your lobby/free run/what have you, unplug/plug back in your wheel, then press your pedal, you will see that almost instantly on the first press, it will spike, and hold the spike all the way until the pedal is fully pressed. This is how the wheel "learns" the distance fully released to fully pressed pedals.
With that in mind, I'll address this: "Your car's brake does not operate by merely resting your foot on the brake pedal. So too should there be some movement on the brake pedal of a sim car. In the case of the G27 there is no play to speak of and I thing that this may well be giving us all this spiking problem. In additioin to above opinion lets look at the brake pedal itself."
This is set in game, not by the wheel itself. Typically in a sim racer, this is actually an adjustable variable, in both the wheel, and all of the pedals. Its called deadzone, however, it is a static setting in GT5.

Edit:
Something else to add. I have also found while changing around springs one day (have my pedals inverted) I did it while in a lobby. Swapped springs, and went to drive again, and found that my pedal was holding a slight accel while the pedal was fully released. I figure that was cased by the pedal actually taking the pot back, past the initially set zero when swapping the spring. Once the new spring was in and bolted up, the new set zero was set a bit behind the proper zero, and so it caused the accel to act as if it where depressed slightly.
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Thanks for your response. my opinions is based on looking at the physical mechanics of the pot & pedal and not the electronics or the setting up of the G27. Of the setting up regarding as you say the PS3 will calibrate its own max & min brake setting. I've tried doing what you advised but I'm still getting spiking. I have a spare pedal that I stripped to do my investigating. I did not remove my rig's pedal. What I did do was to disconnect the brake's pot and connected the new pot, so,that I could operate the brake by hand. With the new pot connected and turned right down to zero I drove around the track a number of times during which I did not get a solitary spike. I re-connected the original pot and immediatly started getting spikes. While operating the new pot by hand I could see that an extremley minimal rotation of the pot is required to start braking. This led me to believe that a slight bit of leeway between zero and and the start of actual braking would solve the problem. At present my setup is as the day I bought it. I will however modify the shaft of the new pot and replace it, it may well just be that the pot is just faulty and actually needs to be replaced. I also have other problem which does not actually have a negative effect while racing but if I brake to a standstill regardless of what gear I'm in the revs drops down to idling only for a very brief moment, then starts to increase rapidly right into the red while I still have my foot on the brake as if the gears was in neutral. I can't imagine why the brake pedal would trigger the increase in revs bearing in mind that the gas pot is at zero. It seems there's a current flow from the brake to the gas circuit, as to how and why, I don'd have a clue. I'm sure an electronics expert can fathom it out. If Sony could only get their act together and have an expert available on this forum to assist with our problems. Again thanks for your input, that's how we learn. Cheers!
 
" I also have other problem which does not actually have a negative effect while racing but if I brake to a standstill regardless of what gear I'm in the revs drops down to idling only for a very brief moment, then starts to increase rapidly right into the red while I still have my foot on the brake as if the gears was in neutral."
Now this sounds like the original issue I described. Check your wires. That sounds like the wires are pinched together somewhere and causing a short.
 
Yo
Rallywagon
" I also have other problem which does not actually have a negative effect while racing but if I brake to a standstill regardless of what gear I'm in the revs drops down to idling only for a very brief moment, then starts to increase rapidly right into the red while I still have my foot on the brake as if the gears was in neutral."
Now this sounds like the original issue I described. Check your wires. That sounds like the wires are pinched together somewhere and causing a short.
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You could very well be right, its gotta be something of that nature, it might even be the same fault that is causing the spiking in the first place. If the brake can affect the gas then it is logical that the reverse can also happen. Never thought of connecting the two problems to a common fault.
 
all three pedals share a common positive feed (red) and a common ground (black). then each has a separate "signal" wire. Brake is white, gas is orange.
2013-11-17151502.jpg


From where my hand is in the lower left, up to that junction in the wire loom in the center of the picture, that short span is where the likely short is at. however, check the length of your pedal cable and the length of the USB cable to be sure there are not kinks or crimps anywhere in the wire as well.
 

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