[JrZook]

Hey all!

Quite a few questions on here about the VSS which is required on the seirra speedo head for G16 EFI conversions I decided to investigate and make one up considering some prices they were selling for . Armed with a spare sierra speedo cluster (thanks to Jas and the Sunny coast wreckers) and a bottle of bundy red I pulled it apart to figure out its mistery.

Speedo unit removed from the dash cluster, pretty easy only a few screws here and there:


Take the speedo unit apart carefully has a very small calibrated wound spring and other small bits. Only 2 screws are holding it together, you can see these in the above pics and this is what your left with. It a magnetic drive disk! Pretty neat and simple. Has 4 magentic poles built into the material North,south,north,south.


Tried measuring the pulses with a hall effect sensor that had a built in schmitt trigger. That worked but gave me 2 pluses per rev. Jas with his vit cluster clarified that it should have 4 pluses per rev. No problemo. Went out to jaycar, bought a reed switch and mounted it to a piece of vero board.


Placed it under the magnetic disk and presto 4 pulses per rev!!


This is as far as I've got only thing to do now is mount it to the head and put the speedo back together. Install in cluster with a wire to the VSS input to the computer, the other to ground.

Dan

[want33s]

Good work Dan.

[joeblow]

nice!

[morpheus]

you know what i like about this. its one of those things most people would not bother doing, but u sat down and thought about it, and also knew enough to make it all work. and how simple is it, and i bet it saved u a heap of $$ and stress..

good work..

[want33s]

I can't wait till the royalty cheques start rolling in!

[Joe]

wow your a smart little bugger good stuff matey

[atari4x4]

that is simply awesome


auszookers brings the tech!!!

[Rusho]

I know 3/5's of SFA when it comes to these things...I assume this will replace the need to find a Vit cluster and adapt to the sierra cluster? Will you be producing these for fellow zookers??

Sorry for the silly question

[dank]

Have a look in the speedo unit of an EFI Toyota starlet dash cluster...you might be pleasently surpirsed what you find in there....

oh nice work on the tech as well...I don't know if its just me but both here and outers has been seriously lacking some decent tech in the last few months....

[JrZook]

Thanks for the replies guys. Yea just thought it would be handy to try and explain how it works and what it looks like to fellow zookers. I hate 'black box' things ie don't know what they are doing.

Rusho81 wrote:

I know 3/5's of SFA when it comes to these things...I assume this will replace the need to find a Vit cluster and adapt to the sierra cluster? Will you be producing these for fellow zookers??

Sorry for the silly question

Correct!! This way you wont need to hunt around for a vit cluster and tear that dash apart also. Can adapt it straight to the sierra speedo unit. Did up the thread so some could sort of follow it to make up there own. Guess I could make some up and install it if given the dash cluster.

At the mo its still a proto so I will test it out first, then neaten it up a bit.

Dan (Bring back the TECH!!)

[JrZook]

Ok didn't like the board I started with (wasnt up to my standards of neatness) so made another one. Fits alot better now and looks the part!


New board custom ground to fit the speedo head snuggly.


Board fitted to the magnet disk assembly and into cluster


Connections to the cluster wiring. Top screw is ground and has been grounded through the tracks underneth it. Bottom screw has the VSS conenction which will go to the comp via an earth lug style terminal.

Now to install it into my speedo and test

Dan

[31zook]

your build and all the nifty stuff you come up with just keeps me amazed. Nice

[want33s]

The tide mark in the cluster above reminds me to drill some holes in mine to let the water out when I Gerni the interior....

[JrZook]

Well it works perfect!!! No more crappy engine check light!!! The comp definatly seemed to be in some sort of limp mode before the VSS. Idle has dropped and smoothened out, pickup at speed is much better!! Be interesting to see if it changed the ecomomy much.

Dan

[Stuey]

That is very nicely done. I'm sure your efforts will go on to help many.

This is the sort of stuff I enjoy tinkering with too. What kind of background do you have to have an understanding? Is it a hobby or have you had some professional training of sort? I studied electrical engineering at uni (which just seems to mean I'm the chosen one in the family to tune in the oldies prehistoric TV and VCR). As i'm sure you can appreciate, Jaycar is a bit of a nerds toy shop heaven!

And I totally understand your black box reference.

[bakerboy]

Thanks a million JrZook!!

[jimbo_jones]

good work

[Fatzook]

Where are you located and what would you be asking to do this conversion? I have a vit speedo in mine, but would prefer your method.

Cheers
Pete

[Damo]

Fatzook wrote:

Where are you located and what would you be asking to do this conversion? I have a vit speedo in mine, but would prefer your method.

Cheers
Pete

Pete, check your email.

[bagnkat]

JrZook wrote:

Well it works perfect!!! No more crappy engine check light!!! The comp definatly seemed to be in some sort of limp mode before the VSS. Idle has dropped and smoothened out, pickup at speed is much better!! Be interesting to see if it changed the ecomomy much.

So Dan, it's been a while. If the car's been on the road a bit to test it, how much do you reckon the fuel economy and power has improved?

[JrZook]

bagnkat wrote:

JrZook wrote:

Well it works perfect!!! No more crappy engine check light!!! The comp definatly seemed to be in some sort of limp mode before the VSS. Idle has dropped and smoothened out, pickup at speed is much better!! Be interesting to see if it changed the ecomomy much.

So Dan, it's been a while. If the car's been on the road a bit to test it, how much do you reckon the fuel economy and power has improved?

Hahah settle down!! Haven't done much k's on it yet to comment on fuel ecomony. Seems to go alright and seems to have more poke around the 100KPH mark! That said the idle has also dropped a few hundred and is smoother most likely due to teh comp not running in some sort of limp mode. I will get back to ya on the economy!!

Dan

[bagnkat]

Cool, I'm mainly interested in increasing the economy to get better range. I know that mine doesn't have a VSS, and that the exhaust pipe is black as. As I understand it, (someone correct me if I'm wrong), one function of the VSS is to lean out the engine with forward speed. I'm gonna give your VSS a go and I'm curious as to how much my engine is currently choking itself.

By the way, thanks for putting up an excellent solution that I for one wasn't aware of.

[JrZook]

No problems!

So what are the specs on your car? My last fill up with the VSS I got 250k's out of 27.5L. Sierra running 30's WT diff ratios and 4.9:1case. Now this 250ks was exactly what the tripmeter read no adjustments. With my proto speedo/odometer project ive found that the tripmeter is out about 15% with these tires. So that equates to 287.5k's/27.5l or 10.5ks/l. This was all stop/start town driving.

What sort of economy do you get?

Dan

[Damo]

bagnkat wrote:

As I understand it, (someone correct me if I'm wrong), one function of the VSS is to lean out the engine with forward speed.

Deceleration enrichment. The VSS is used by the ECU to tell when a low load condition is happening, and backs the fuel off.

[JrZook]

Damo wrote:

bagnkat wrote:

As I understand it, (someone correct me if I'm wrong), one function of the VSS is to lean out the engine with forward speed.

Deceleration enrichment. The VSS is used by the ECU to tell when a low load condition is happening, and backs the fuel off.

And also ignition timing trimming due to the 'aerodynamic' load which is a function of vehicle speed.

Dan

[JrZook]

Damo wrote:

bagnkat wrote:

As I understand it, (someone correct me if I'm wrong), one function of the VSS is to lean out the engine with forward speed.

Deceleration enrichment. The VSS is used by the ECU to tell when a low load condition is happening, and backs the fuel off.

Probs actually be called deceleration enleanment

[Damo]

JrZook wrote:

Damo wrote:

bagnkat wrote:

As I understand it, (someone correct me if I'm wrong), one function of the VSS is to lean out the engine with forward speed.

Deceleration enrichment. The VSS is used by the ECU to tell when a low load condition is happening, and backs the fuel off.

Probs actually be called deceleration enleanment

Enrichment with a negative value

[bagnkat]

Damo wrote:

The VSS is used by the ECU to tell when a low load condition is happening, and backs the fuel off.

Righto, that makes sense...

[bagnkat]

JrZook wrote:

No problems!

So what are the specs on your car? My last fill up with the VSS I got 250k's out of 27.5L. Sierra running 30's WT diff ratios and 4.9:1case. Now this 250ks was exactly what the tripmeter read no adjustments. With my proto speedo/odometer project ive found that the tripmeter is out about 15% with these tires. So that equates to 287.5k's/27.5l or 10.5ks/l. This was all stop/start town driving.

What sort of economy do you get?

Okay, so I've got a coily with 30's, a 1.3 leafy transfer case and as it's my daily driver, I do mostly highway driving. Corrected distance travelled is 449km. Fuel used was 54.66L. So a crappy 8.2km/L is the result. This is with standard unleaded (91RON no ethanol). With 95RON, I do a little better.

[oozuk]

Maybe I've missed something, doesn't the Vitara speedo with the vss just bolt into the Sierra speedo cluster ? That's what I did in the past. Maybe I've missed something obvious.