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Author Topic: Calculating Gear Ratios  (Read 8076 times)
adam-
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« on: November 11, 2015, 07:01:11 AM »

Hello.

Bit of a stupid one, but I've swapped out my box with a generic 6 speed 02J and obviously the ECU now has no idea about what gear (gangi) it is in.

How does it know the ratio?  Obviously speed/RPM gives a ratio, which is in NVQUOT.

But, how can I calculate values for it so it knows again?  Can I just log RPM and speed and calculate ratio by dividing RPM and speed to get a ratio?

So, do 1500 rpm in first, second, third, forth and fifth.  Log speed and RPM and then?
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adam-
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« Reply #1 on: November 11, 2015, 02:34:25 PM »

Okay, so defined all of the NVQUOT1O NVQUOT1U, 1 through 6 gear.  Does anyone want to explain why there's 3 sets of each variable?

So, I copied over the values from a 1.8t Polo GTi as a base, because the other files I had defined had stupid values that made no sense for upper and lower limits.

Went out and logged, have no gear.  I'm not seeing a vehicle speed and I'm not too sure why.  Checked the Wiki and found AIMVM, but that made no difference either.

Not really sure why I'm not seeing vehicle speed, how is it calculated?  It's reporting 0km/h until what feels about 15mph, then it reports 1.  Until about 30mph, it reports 2, then what feels like 40mph, it'll report 3.

Almost like it's a factor of 10 out.  Thoughts?
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ddillenger
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« Reply #2 on: November 11, 2015, 02:37:05 PM »

Variant coding (re: multiple sets).

As for your VSS, not sure what you are saying....
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adam-
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« Reply #3 on: November 11, 2015, 02:40:41 PM »

I thought that, but how do you know what variant it's using?  I''ll set them all to the same until I get this working, then adjust until I know what variant.  Assuming the variant number is consistent throughout (for other functions).

Sorry, I'm tired.  I've logged VSS and I have no response in VCDS (I was seeing 0 vehicle speed with me7logger but thought it might be because the cluster fuse was pulled, so tried VCDS).

It's hard to explain, but if I'm doing about 15mph, VCDS will report that I'm doing 1.0km/h.  Go to 30mph, and VCDS will report 2.0km/h.  40mph and it'll report 3.0.

No decimal coverage, just integers.  Reading up just now where it gets it's speed from, I think it's CAN.  The cluster reports VSS in km/h absolutely fine.
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adam-
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« Reply #4 on: November 11, 2015, 02:44:09 PM »

Attached is the gangi log.  You get the idea though.  Literally no gear selected because VSS is 0.
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ddillenger
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« Reply #5 on: November 11, 2015, 03:15:20 PM »

check the variant table. That will usually shed light to the order. _0_A is usually VARDEF however. Just change them all.
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adam-
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« Reply #6 on: November 11, 2015, 03:22:32 PM »

I have.  Just had a look at the numbers, what bollocks.

Does anyone have reasonable numbers for an 02J 5 speed from a MK4 1.8t.  I'll look tomorrow, but just in the off chance. 
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adam-
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« Reply #7 on: November 11, 2015, 03:24:59 PM »

Still think that is irrelevant at this stage - I'm still not seeing VSS, even though the cluster is.  Hmm.
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adam-
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« Reply #8 on: November 12, 2015, 03:08:27 AM »

Thought I'd try and be clever and flash the original DR file onto it, even though I'm running an HN version.  Started and killed.  No start from immo.  Great.

Going to try the spare key when I get home, but I can't communicate with it, so it's bootmode time.  However, when I could connect, block 66 saw vehicle speed, whereas before it didn't.

What is different between the HN file and the DR file so that the DR one sees speed, but the HN one doesn't?!
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adam-
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« Reply #9 on: November 12, 2015, 05:41:42 AM »

For the record though, launch control works fine, the vehicle speed variable adjusts file and it notes speed fine.  Why can launch see speed fine, but block 66 doesn't?

Do I need to go back to the original file and make all my changes again?! :/

What gives?

EDIT: By the way, when I swapped the DR file onto it and could still connect, the ECU saw block 66 fine, no issues.  What is the difference in software between the DR and the HN?
« Last Edit: November 12, 2015, 05:53:59 AM by adam- » Logged
adam-
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« Reply #10 on: November 12, 2015, 05:04:58 PM »

I recovered the ECU in bootmode which I'm going to write up, as the information is a bit scarce. I'll try and get something together over the weekend.

What I discovered is that the DR file sees vehicle speed absolutely fine (in block 66).  I never got to see if it recognised gear, but I'll assume it does.  However, the HN file that I'm running on the ECU DOES NOT RECOGNISE SPEED.

Why?
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adam-
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« Reply #11 on: November 21, 2015, 02:45:11 PM »

Shameless bump.  Still not getting anywhere.  Tried an HJ file which sees speed in block 004 and 066 but when logging gangi I've got nothing.

It doesn't see vehicle speed (I'm logging vfzg).  Does anything have any thoughts?
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SB_GLI
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« Reply #12 on: November 22, 2015, 10:23:10 AM »

coding in vcds correct?  do you have to log with the cluster fuse pulled by chance?
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adam-
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« Reply #13 on: November 22, 2015, 12:40:47 PM »

I wasn't aware the ECU coding could really change.  I'm going to check the speed sensor on the box to see if it's that, because I'm not sure if the cluster is seeing speed from the ABS or the box.

I've got a wiring diagram to chase too.  Going to get a maps file and EEPROM to flash over because his works, not sure if it's file related.
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adam-
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« Reply #14 on: November 23, 2015, 03:10:38 PM »

Unplugged the speed sensor on the box and the cluster STILL sees speed.  I think that the cluster must pick up speed from the ABS and the ECU from the gearbox.  Well, that's what I hope.

I'm going to swap out the sensor with a good one and hopefully that solves my issue.
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