Speedometer (revisited)

[Davidljones88]

I gave in and dropped the Goblin at a local mechanic that I trust. No one can seem to figure out the speedometer issue (doesn't work at all).

The car was an 08 turbo ss. It has a 2009 SS turbo BCM. The motor is a LDK with z54 turbo and f23 trans. There's not much original on it. It has a zzp pcm.

The obd2 is picking up the mph, but there's a data transfer issue to the bcm I presume. The tachometer works. The speedometer didn't work with the original cluster either. I replaced the cluster with a white cluster fitted for an 08-10 (140mph top speed)

The previous owner had a cheap $30 digital gauge plugged into the obd2. The speedometer wouldn't work on it either.

Any advice? I don't really want to get a stand alone gauge. I'd rather have things working as they should or remove the cluster entirely. I don't really want to rely on gps either.

 

[Gtstorey]

Mine is receiving speedometer data onto the network. It will show up in HP Tuners and my tech2 clone.

if you really want it to work see if you can get a GM tech to use a real Tech2 device to run the speedometer stepper motor test. That’s the only thing that I have found that my tech2 clone doesn’t do. The service manual test is basically to check the stepper motor and replace cluster if the stepper motor test fails.
If yours passes the stepper motor test, I don’t know what else there is to do. If it’s getting the other data through the network, I’m don’t know what can be keeping it from getting to the cluster. If it can be read on the scanner data the data is there and all of the data gets to the instrument cluster through the one green wire. Unless it’s sees implausible data because someone has changed your settings in the ECM tune maybe.

 

[Davidljones88]

Mine is receiving speedometer data onto the network. It will show up in HP Tuners and my tech2 clone.

if you really want it to work see if you can get a GM tech to use a real Tech2 device to run the speedometer stepper motor test. That’s the only thing that I have found that my tech2 clone doesn’t do. The service manual test is basically to check the stepper motor and replace cluster if the stepper motor test fails.
If yours passes the stepper motor test, I don’t know what else there is to do. If it’s getting the other data through the network, I’m don’t know what can be keeping it from getting to the cluster. If it can be read on the scanner data the data is there and all of the data gets to the instrument cluster through the one green wire. Unless it’s sees implausible data because someone has changed your settings in the ECM tune maybe.

If the test fails do you think it's just a wire disconnected somewhere? I've tried three clusters. The current cluster had only 1700 original miles (like new). Would a ground wire cause the issue but still allow the tach to work?

 

[Sluggonaut]

My cluster works just fine but I really don't look at it and use Torque Pro on my phone. I now understand why people ditch the cluster and use a tablet in front of the wheel.

 

[Gtstorey]

There are two grounds from the cluster. I haven’t ever confirmed that mine has both connected, so it’s possible.
Did you confirm GM part numbers on your clusters to see that they match? Typically there will be sticker with the number on it. The NA SS has a different part number than the Turbo

 

[Davidljones88]

I just put on a 160mph cluster. The speedometer will not move while driving, but it will pass a sweep test. Any suggestions?

 

[Dale E]

Have you checked your transmission sensor connection? is it plugged in? Has the sensor failed?

You could always go old school and do an old VW cable driven speedometer through the front wheel??

 

[Davidljones88]

I was sent an automatic speed sensor instead of a manual one.

 

[Gtstorey]

I was sent an automatic speed sensor instead of a manual one.

????
Not sure that would matter if speed is being transferred on the data network, but I guess there could be a logic test that the cluster doesn't pass.

Was the speedometer that passed the sweep test the original that was in the donor? I still feel like the original failed and the other clusters are not the correct part number to work. But I don't have anything to back that up.

 

[OptimizePrime]

My guess: It's your speed sensor vs reluctor teeth and what you have set as your vss pulses.

When I went from an F35 to F23 and didn't set the right VSS Pulses my speedo was all out of wack. My guess is if you were to put in the right speed sensor you'd be fine if you haven't swapped transmissions or messed with vss pulses in hptuners.

Speedometer vs VSS Pulses / Mile

My smooth brain has never heard of VSS Pulses / Mile until just recently. If you're familiar with it's purpose and calc, this won't be that interesting. If you have modified your wheel & tire size and / or changed the transmission final drive you're going to want to update this value in HPTuners...

dfkitcar.com

 

[Rauq]

My guess: It's your speed sensor vs reluctor teeth and what you have set as your vss pulses.

When I went from an F35 to F23 and didn't set the right VSS Pulses my speedo was all out of wack. My guess is if you were to put in the right speed sensor you'd be fine if you haven't swapped transmissions or messed with vss pulses in hptuners.

Speedometer vs VSS Pulses / Mile

My smooth brain has never heard of VSS Pulses / Mile until just recently. If you're familiar with it's purpose and calc, this won't be that interesting. If you have modified your wheel & tire size and / or changed the transmission final drive you're going to want to update this value in HPTuners...

dfkitcar.com

Don't know how I missed this, that's 100% your issue. It's not the sensor, it's the tone ring on the differential that's got a different tooth count in the F23 vs F35 that requires this setting to be updated in the tune.

Maybe I was so flabbergasted at the suggestion of a cable driven speedo that I totally glossed over the F23 comment in the original post.

 

[Scott #321]

I was sent an automatic speed sensor instead of a manual one.

Based on Autozone it looks like different sensors for the automatic and manual transmission.

 

[Gtstorey]

Don't know how I missed this, that's 100% your issue. It's not the sensor, it's the tone ring on the differential that's got a different tooth count in the F23 vs F35 that requires this setting to be updated in the tune.

Maybe I was so flabbergasted at the suggestion of a cable driven speedo that I totally glossed over the F23 comment in the original post.

How is he getting speed reported over the data network? Or maybe it isn't.

 

[Rauq]

Based on what I recall in the short time between completing my swap and flashing the revised tune, it was like the computer got wigged out with a significant disagreement between RPMs and what it would expect to see from the trans output speed. The F23 tone ring would signal about 1/3 the speed of an F35 tone ring, so it was stuck between "you're somehow doing 0.4 mph at 1500 rpms" and trying to run the park/idle area of the tune while driving.

 

[Gtstorey]

I have the same symptoms as DV88 although I'm not running the F23. I get an accurate speed reading on the OBD2, both HPT and Tech2 clone. I've tried a couple of different ICs although I've never had one that matches part #.