R32 Gtr G Sensor Fix

[Gt-r_James2]

Thanks for the link GTRPSI,

I'll find someone to replace caps in my G-sensor soon, hopefully this will return it to its proper function, I'm getting tired on hooning around in an overpowered Gts-t.

Anyone have recommendations for somewhere in Sydney that can replace two caps on a circuit board? I'm all ears.

Thanks

[GTRPSI]

The electronic techs over at Austech should know someone or you could go to any electronics repair shop or someone who does Tv;s, however have a look at my reply over there, you may want to check if the Atessa ECU is getting the 2.5 V at its end also in case you have a break in your wiring harness or a bad connection under the rear parcel shelf.

As i mentioned, do any of the caps look burnt?

Edited January 29, 2012 by GTRPSI

[Gt-r_James2]

Yeah I plan on testing the voltage at the computer end when the weather clears up. Can you post the wiring diagram you mentioned? I couldn't find where you put it on Austech, The 32 Gtr manual would be awsome as well!

One of the caps looked burnt out and took it into jaycar for a second opinion and guy I spoke to said it looked fine (??)

For others out there with this problem I stumbled accrossthis part http://www.nengun.com/do-luck/digital-g-sensor I think I'll persist in tyring to fix the factory unit but if your at the end of your tether than its a better option than forking out 2K to nissan.

[xiaorpowr]

okay this is my last ditch attemp at fixing this... if it doesnt work, im gonna go with the do-luck unit

So can you guys post up the specs or part number or any info about the replacement caps?

I've taken the damn thing to Jaycar and another electronic parts store and both had no idea what i can replace it with.

Thanks, appreciate your help!

[datsun_1600]

okay this is my last ditch attemp at fixing this... if it doesnt work, im gonna go with the do-luck unit

So can you guys post up the specs or part number or any info about the replacement caps?

I've taken the damn thing to Jaycar and another electronic parts store and both had no idea what i can replace it with.

Thanks, appreciate your help!

Hey Mate, (replying to your PM here)

So I replaced the caps with three of these (prolly only need two) http://au.element14.com/rubycon/35ml10mefc4x7/capacitor-10uf-35v/dp/8126542?Ntt=812-6542

I replaced the trimmers with these http://au.element14.com/bourns/3303w-3-203e/trimmer-20k-3mm/dp/1689841?Ntt=168-9841

I also replaced one of the 200K ohm resistors (not mentioned in this topic) with a trimmer http://au.element14.com/bourns/3314g-1-204e/trimmer-200k-4mm/dp/1689909?Ntt=168-9909 as I couldn't achieve the correct 2.5v

I have some parts here .... Where are you located - maybe I can take a look ? (I'm in Adelaide, but travel to Vic now and again to see my family) Or if you want just send it my way and I can replace the parts, test it, and send it back.... Maybe it's not the G sensor ??? maybe it's actually in the wiring back to the computer ? (or maybe the computer ??)

Anyway - good luck,

Jeff

P.S. make sure you have the car running (idle on level ground) when you set the pots, I found they changed after the car was started...

TTYL,

Jeff

[GTRPSI]

That cap Jeff linked back to is exactly the same one i used.

Leave a little leg on the cap so after you solder it in you can bend it over so the cover fits on.

Take note that the silver stripe running down the side is the caps negative terminal side, dont put the new one in the wrong way.

Edited February 11, 2012 by GTRPSI

[xiaorpowr]

Thanks for all the info guys, really helpful. I left my sensor with a TV electronics tech. I'll just send him the part specs and hopefully he can do the soldering and for me.

Cheers for the offer to help Jeff. I'm in Syd, but I'll see how I go wtih the Tech 1st.

Also, I'm sure its the G Sensor thats causing the issue. I had followed your pot adjustment process you wrote about earlier in this thread, one pot wouldnt goto 2.5v but that process did make the sensor work more reliably, so hopefully if I referb the whole thing with those parts, it will work!

[datsun_1600]

That cap Jeff linked back to is exactly the same one i used.

Leave a little leg on the cap so after you solder it in you can bend it over so the cover fits on.

Take note that the silver stripe running down the side is the caps negative terminal side, dont put the new one in the wrong way.

I was thinking about this just now and it might be also worth checking for cracked / dry solder joints.... maybe when you have the sensor sitting in the car and it's all nice and stable it works. But when you drive around the vibrations might open up a hairline crack and cause the output to drop out for a fraction of a second - enough time for the error to be thrown.... In my experience the cracks can only be (sometimes) seen under a microscope, so it might be worth re soldering the whole board (easy, but might take half an hour or so).... Just a thought anyway...

Jeff

[Ronin 09]

Has anyone considered one of these:

http://www.nengun.com/midori-seibi/midori-spec-digital-g-sensor

[R32 TT]

Has anyone considered one of these:

http://www.nengun.com/midori-seibi/midori-spec-digital-g-sensor

Wow. Did not even know about this. How long have they been around ?? Anyone using one?

[Ronin 09]

Yeah I'm keen on it; buy one and reverse engineer?

[SiR_RB]

Can I have some more specific info on how to check the voltages on the g sensors? What colour cables do we check? Do we test the cables going to the g sensor or going to the attessa ecu?

Realy need to check my voltages are at 2.5v each

And also how do you turn them up or down to adjust? Are the adjustment screws in the g sensor?

Sorry for all the questions but realy need to get this sorted

[datsun_1600]

Wow. Did not even know about this. How long have they been around ?? Anyone using one?

I think that looks like a neat product - but I wouldn't believe this part "When cornering and you have broken traction, the stock G sensor would delay in sending this information" In reality, even though the stock G-Sensor is old, it works via old school analogue electronics (meaning it has no way to "delay" anything!!! - there is almost zero "delay".) The only thing that I can think of is the filtering technique:

In the original Nissan G-Sensor it uses silicon fluid (thick goo) to slow down the movement of the sensor arms to filter out car vibration, slight jerks etc. I'm guessing this product uses a digital filter to do the same thing, thus allowing the ability to really fine tune what the ATTESA computer in the boot "sees". I tried removing the dampening fluid from the G-Sensor, sure the 4WD system comes on really quick, but that's not what you always want.... And having it engage every time you go over a little bump is no good.....

I think the real "delay" comes from the ATTESA computer in the boot - not the G-Sensor...

For ppl interested I still haven't given up on my replacement PCB - just so busy with work I never get a chance to work on it. :-(

just my 2c

Jeff

[endless]

Some info here.. Sounds like it would be a worthwhile buy.

http://www.r33gt-r.com/p/select-gt-r-magazine-articles.html

http://gtr.co.uk/forum/158861-digital-g-sensor-improve-attesa.html

[xiaorpowr]

Just reporting back guys, 4 weeks since I've replaced the caps and did the voltage adjustments.

One pot I could only get to 2.4V but its all good, no longer sends a error code to the ATTESSA ECU. So ABS and 4WD lights have been off the whole time and have been enjoying the safety of 4wd in this horrid sydney weather.

Big thanks to Jeff and Peter good shit. One question, do you know what are the implications of a 2.4V signal instead of 2.5V? would it result in less front torque split or anything like that?

I will work on replacing that adjustment pot in the future I think. Thanks again.

Can I have some more specific info on how to check the voltages on the g sensors? What colour cables do we check? Do we test the cables going to the g sensor or going to the attessa ecu?

Realy need to check my voltages are at 2.5v each

And also how do you turn them up or down to adjust? Are the adjustment screws in the g sensor?

Sorry for all the questions but realy need to get this sorted

SiR RB - take a look at the 1st post where Jeff (Datsun_1600) posted a facebook link to a picture, that is how u measure the voltage and you adjust by spining the round things. Start with that man, if you can get a hold of a GTR service manual it will tell u which plug u measure going into the ECU... but looks like the G sensor is the weak point, so do that 1st.

[datsun_1600]

Just reporting back guys, 4 weeks since I've replaced the caps and did the voltage adjustments.

One pot I could only get to 2.4V but its all good, no longer sends a error code to the ATTESSA ECU. So ABS and 4WD lights have been off the whole time and have been enjoying the safety of 4wd in this horrid sydney weather.

Big thanks to Jeff and Peter good shit. One question, do you know what are the implications of a 2.4V signal instead of 2.5V? would it result in less front torque split or anything like that?

I will work on replacing that adjustment pot in the future I think. Thanks again.

SiR RB - take a look at the 1st post where Jeff (Datsun_1600) posted a facebook link to a picture, that is how u measure the voltage and you adjust by spining the round things. Start with that man, if you can get a hold of a GTR service manual it will tell u which plug u measure going into the ECU... but looks like the G sensor is the weak point, so do that 1st.

Hey Mate, that's great news. Depends on which pot. I had one of my pots sitting at 2.4 volts for ages and didn't notice much difference. One thing that will happen if it's running right on the edge is that you might see the fwd bias indicator flicker (ie just to say 1~2%) when you wouldn't expect it. In the end if I was driving up a hill it was enough to trigger the 4wd system... I made another mod not listed on this forum to fix this. If you want to change out a resistor to fix your 2.4v issue (ie can't get the right voltage with the factory pots) just post here and i'll do another write up and post pics.

Jeff

[SiR_RB]

yeh sorry mate didnt see the pic as i dont have facebook, but i got it through a mate

i did the test yesterday and all the voltages were around 2.65v so i turned them all down to 2.5v

4wd light still on, cleaned my front wheel speed sensors aswell,,,,i think it has an earth problem as the ATTESA ecu is throwing a shit load of codes all of a sudden, or the ATTESA ecu itself is stuffed

not gonna touch or change anything until i get the system flushed with fresh oil and bled properly in the coming weeks

[datsun_1600]

Thanks for the link GTRPSI,

I'll find someone to replace caps in my G-sensor soon, hopefully this will return it to its proper function, I'm getting tired on hooning around in an overpowered Gts-t.

Anyone have recommendations for somewhere in Sydney that can replace two caps on a circuit board? I'm all ears.

Thanks

So long story short James sent me his G- Sensor to have a look at. Thought I'd document the attempted fix attempt here...

First inspection showed that the electrolytic caps had died and leaked acid all over the bottom of the PCB.

(Hopefully I get the pics in order here) You can see the black pads and discolouration around the caps and IC's where the acid has leaked in this pic.... (Pic 1)

So time for some cleaning.... This is what I normally use.... (Pic 2)

It will get most of the crap off – but there will still be a bit left in the joints (Pic 3)

After a good clean I resoldered all the joints that were corroded. As the joint is re-soldered the black acid crap from the caps will come out of the joint. So the process goes – solder – clean – solder again – clean...

After all this I ran a test and found the two of the three outputs were now working great and could be adjusted via the factory pots to 2.5v– the other one was...well...way low (0.233v). I took the G-sensor off the mount and moved it around and observed the voltage – I could see that is was moving – meaning that the pendulum and thus the g-sensor was somewhat working. The next step is to remove two resistors and replace them with pots to give us a bit more room for voltage adjustments. This can be seen in the last pic (Pic 4)

After some tweaking of these two added pots and the factory pots we now have 2.5volts on all three outputs....

Next comes the testing. I fired the car up and all the dash lights went off, then drove it backwards and forwards a few times in the driveway – all good.

The next step is to take if for a road test... but unfortunately I've run out of time and have to get some work done. I'll hopefully have a crack at it later tonight.... If it all works then the PCB just needs a good clean and some hot glue to hold down the components added...

The reason one of the outputs was low seems to be because the pendulum arm is slightly bent (crash maybe) or perhaps the hall effect sensors are on the way out.... Another interesting point is that it ALWAYS seems to be output "2" that is bad....

Sorry for the bad English – wrote this really really quick!

Jeff

Edited March 8, 2012 by datsun_1600

[datsun_1600]

OK - So I took the car and G-Sensor out for a road test last night. It ran almost fine for the for 30mins then when I was out of city limits and was able to give it a bit of stick I noticed the 4WD split gauge ramped up very quickly to 50%. Then when I did a launch from 1st gear it triggered an error code.

I played a little with the two new pots to help eliminate this but as it was dark and I was in a rush I didn't the adjustments fine tuned.

Is summary, it seems to be very close to working, but needs some fine tuning - which I most likely will not get done till after March 24th due to wedding stuff...

Anyway - looks like it should be fixable!

Jeff

[RacerXGTR]

Jeff,

I followed your tutorial and my voltages are way off even after adjustment. I got 2.45, 2.6, and a pot that cant go past 1.9. The electronics store I have on island (Okinawa, JP) doesn't have the pots so I'm kinda stuck. Here's where my real question comes in....I didn't get the 4WD light on until I was removing tint from my back window (also turning my car off and on occasionally for some background music). Is it possible that I just smashed on a wire somewhere around the back seats and broke it that way? I am getting error code 13 which to me sounds like it has a connection to the sensor but still it hangs in the back of my mind about looking in the wrong place. I'm interested in buying a completely electronic system like the one you're making and there is another one built and currently being tested over Here