CoolGuy094

Something is amuck with the way I have my Dakota Digital speedo calibration unit setup and I can't figure out what it is. I've set it up exactly how Idiot Muscle's instructions say to, but from what I've seen so far these instructions aren't much to rely on.

I've got the dip switches set as follows:
#1 UP
#2 UP
#3 DOWN
#4 UP

I have the stock Honda rear end with the stock 4:10 gears, And I just re-confirmed my calibration is set as:
Coarse: 13
Fine: 7

I've got the input coming from the VSS sensor, OUT2 goes to the Honda ECU, and OUT3 goes to the GM ECU.

This is exactly according to the IM instructions.

However my speedo reads 30 MPH when im actually traveling at 80 MPH. This is so far off that changing the coarse/fine calibration won't get me to a correct reading.

Anyone know what's going on or can share their settings on their unit?

CoolGuy094

SGI Setup Manual Linked Here

According to the manual, dip swtich #3 controls the type of input/output signals being read and sent.

From what I've gathered reading through posts here and on LS1tech, the stock Honda trans and sensor should have about a 145k-160k PPM reading coming straight from the sensor. That then splits and goes off to the ECU as well as to the cluster. Inside the cluster, it gets leveled down by a factor of 40 to produce a 4k PPM signal to the EPS, cruise, and soft top modules. So the key here is that the ECU and cluster want to see this 145k-160k signal coming into them in order for everything to work right.

The T56 produces 17 pulses versus the Honda's 46 pulses; a ratio of 0.37:1. So that should produce around 54k-59k PPM reading coming straight from the sensor. According to LStech, the GM ECU wants to see 4k PPM at the VSS input for the ECU.

The SGI manual shows two options for input signal coming from the sensor... 64k-256k, or 4k-16k. You select either range by setting dip switch #3 either up (for 64k-256k) or down (for 4k-16k). If I'm sending it 54k-59k straight off the sensor with the T56 trans, then I'm assuming I should choose the 64k-256k setting. Import Muscle tells you to set dip switch #3 down, which would select the 4k-16k input range, which I believe is wrong.

The output that goes to the Honda ECU and cluster, according to Import Muscle's instructions, is OUT2. Again referring to the SGI manual, that output with dip switch #3 up would be 128k PPM (open collector). With the dip swtich down, that output would be 8k PPM (open collector). We know the Honda ECU and cluster are looking for 145k-160k, so the UP option would be correct... again another mark against IM's suggestion of DOWN. So sending 128k to the cluster and then modifying the calibration should hopefully get me where I need to be.

Now for a bit more confusion... the signal going to the GM ECU is wired into OUT3 according to IM. OUT3 is 8k (alternating current) if dip #3 is UP, and 4k (alternating current) if dip #3 is DOWN. LS1tech says the GM ECU is looking for 4k PPM. So here, down would be the desirable setting. But if UP on dip #3 is what we need, then maybe OUT3 isn't the best option once dip #3 is set to up. OUT4's output when dip #3 is UP is 4k (open collector). So I may need to switch the GM ECU's signal to OUT4 instead of OUT3. All this being said, you can change the GM ECU's VSS signal in HPTuners, so all of this may be unnecessary. Just send it the 8k signal and modify in HPTuners. But if we can get closer on the actual signal by switching to OUT4 and sending it 4k, then why not.

So in summation, I am going to turn dip switch #3 UP, switch the wire from OUT3 over to OUT4, and see if this thing catches on fire.

Tehk

I'd help but I am using the gm vss unfortunately and a gutted rack

CoolGuy094

Turns out my problem was a wiring mistake. I was grabbing the VSS signal as it exited the cluster, which is after it was already converted inside the cluster. Those damn wire colors are the same and all those bunches of wires get confusing down there.

Corrected the wiring and grabbed the VSS signal directly off the C101 connector as it comes through the firewall. This fixed everything. My calibration ended up being Coarse: 13, Fine: 2 in order to get my speedo to match my GPS reported speed. I did experience one issue when trying to change the calibration while driving, I lost all VSS signal which caused me to lose power steering on the highway (whoops!). Had to pull over, turn the car off/on, and all was well again. So I guess lesson learned, best to set the calibration while stopped.

CoolGuy094

Also it seems like the GM ECU is interpreting the correct speed with no calibration in HPTuners needed. IM had mentioned in their instructions that you would need to calibrate the GM ECU speed in HPTuners, but that wasn't the case for me.

Top readout is recorded GPS speed from phone, bottom readout is the GM ECU speed.



And the speedo speed. Cruise control works without issue.

Luder94

You have cruise control setup? Pics please, would like to see how it's routed in the engine bay.

Thanks.

BTW, you didn't happen to keep AC too, did you?

CoolGuy094

Its just the OEM cruise control. I didn't change anything about it, same mounting location, wires, cable, etc.

I am keeping AC but I don't have all of the lines in yet. I planned on getting that done this winter but now I'm not sure I'll get it done in time for the southern summer. Gonna be a hot one.

Jonathan_ed3

Am I reading correctly? You have WORKING Cruise Control? Literally *everyone* I've ever asked that did this swap using the SGI-5 said they lost cruise function after completing the swap. I never even hooked mine up afterwards because I assumed the signal got lost/mixed/degraded somehow as part of the VSS correction, which made the CC lose functionality.

I can't understand why the CC would work for you but not for anybody else? What am I missing?

Did the instructions from IM end up being correct, with just you grabbing the signal from C101? Or did you make any other alterations?

I ask because the IM instructions, although like 50 pages or whatever it is, leaves a lot to be desired.

CoolGuy094

Yes, the OEM cruise control is definitely working as it normally did. From what I understand, the VSS signal comes out of the VSS sensor, goes to the Dakota SGI-5 module, gets converted, then goes out to the OEM cluster. From there, it gets converted by the OEM cluster and goes out to the OEM ECU, the CC module, and the EPS module. Everything from the cluster onward is still like factory, meaning the signal coming into the cluster has already been converted by the SGI-5 to emulate the OEM Honda signal, so everything from that point on should function just fine as it did from the factory. The SGI-5 intercepts the signal as soon as it leaves the VSS sensor and before it even reaches its first destination (the OEM cluster), so everything else should be unaffected.

I'm not sure why anyone was expecting to lose CC functionality; I had always assumed it would work and kinda kept my fingers crossed that I was right.

The wiring instructions from IM were surprisingly correct as far as the SGI-5 wiring was concerned. There were a few ambiguities here and there but I was the one at fault in this case. However, you're right on their instructions being crap. They gave halfway decent info on the mechanical aspects of the swap but completely went full retard when it came to the wiring.

Jonathan_ed3

Well I too (assumed) it would work before my swap. Never had a reason to believe it didn't. But then I asked around and everyone said it stopped functioning after their swaps, so I gave up on the idea as I started to work on mine. I use CC daily, even on my "fun" cars. I'm gonna put mine back in and hope it works!! Thanks for the info.