TFS355S10

iTrader: (2)

I've been reading threads for a couple hours now trying to figure out what vss I need to be compatable with my tpi system. All I can find is info about making the speedometer work. I just want the tpi ecu to get the right signal to work right.

Mine is a 89 TPI 305 with a stand alone ECU to convert it to speed density. The trans is a 96, (I think) T56, and it's all in a 98 Sonoma pickup.

I seriously doubt if I can make the speedo work at all so I'm not to concerned about it right now. If it would work, that'd be great, but if not I have gps I can use for that anyway. LOL

There has to be a way to put an older vss in the t56 trans to get a signal to the tpi ecm? I was under an older S10, (2.8 V6/T5 5 speed), last night and the speedo hook up on the trans, (assuming this is the vss on a S10?), is the same style plug in as my tpi wiring harness, and looks to be the same size as the one in my T56.
I have no idea about the ppm of it, but if I could use the T5 sensor in my T56 would that solve my delima?
I'm sure I would have to have the reluctor ring from the T5 also.

Tuned Performance

iTrader: (92)

There is a couple ways of going about doing it but the easiest would be to buy a Dakota digital sgi-5 use the 4k ppm input 2 optical out to the ecm. To get the drac to work you may need a second sgi-5. Another choice would be convert the t56 to cable drive and get a 2k retrofit vss.

TFS355S10

iTrader: (2)

But do I really need all the extra gizmos? I would really like to keep this as simple as possible.

If the vss out of the 700r4 would fit in the T56 why wouldn't that work to get the proper signal to the tpi ecm? My particular 700r4 sensor won't fit, but theoretically if it did, it should work, correct?

If the Dakota digital sgi-5 would work to make the speedo work, that would be great. But my main concern is getting the motor to run right.

Tuned Performance

iTrader: (92)

https://www.thirdgen.org/forums/engi...ble-drive.html
http://tpiparts.net/inc/sdetail/7586

Get a vss buffer and go this route and forget your speedo/ drac.

TFS355S10

iTrader: (2)

Not tryin to be rude, but I think you're missingwhat I'm trying to do here. I just want the ecm to get the proper sgnal from the vss to make the motor run in closed loop like it should under normal conditions.
I'm not concerned with the speedo operation at all.

My tpi system, (tpi 305/700r4), came out of an 89 Trans Am. It had an electronic speedo I assume, because the vss is still in the transmission. To reduce it to my way of thinking, the transmission output shaft drives the reluctor wheel, which the vss reads, which in turn sends a signal to the ecm to let it know the vehicle is goin XX mph.
The speedo has nothing to do with all this except on the older cars where the vss was in the instrument cluster. Correct?

To me, every transmission has an output shaft, so all I need is the correct relucter wheel and the correct vss to send the correct signal to the ecm, no mater what transmission the output shaft belongs too. (I realize there would be differences between a manual and an automatic ecm calibration or whatever).

Tuned Performance

iTrader: (92)

I'm not missing anything I understand the speedo operation is not to important. So just buy a sgi-5 and call it a day. The t56 has a 4k magnetic pulse output the sgi-5 can be dialed in for tire size gear ratio error and provide the needed 2k ppm optical signal to the ecm your first cost is the confusion if you are using the 89 tpi maf you are running a 1227165 ecm this take the 2k optical signal. If you are running a 1227730 ecm the buffer is internal just wire the vss to the ecm if its off you can calibrate a little off the division in the ecms calibration. The 730 has a 2k and 4k output so your drac can hit the garbage can and the speedo wire could hook directly to the ecm.

TFS355S10

iTrader: (2)

I think we're both missing something. LOL I cant see any need for the sgi-5 box, and you can't see a way around it.

The system didn't have the sgi-5 box while it was in the firebird, why would it need it now? On top of the extra cost of the sgi-5 box, there's the simple fact that I want to keep the electronics to a minimum because if there's one thing I know about electronics, it is that they will fail. Usually at the worst time.

Think of it this way, my T56 has no output whatsoever. The vss is what makes the 4k magnetic pulse output signal. That vss is what I want to change to get the correct, (2K? signal).

I'm not sure which ecm I have at the moment, I'll have to check that.

There were TPI/T5 manual 5 speed cars, correct? A vss out of one of those would more than likely fit in the T56. The relucter wheel maybe, maybe not. But it could be adapted somehow more than likely.

Tuned Performance

iTrader: (92)

Sorry I thought your t56 had a vss like this.

TFS355S10

iTrader: (2)

It does.

My point was, why not change that sensor to one with the correct output that the TPI system needs?
(Instead of converting the signal electronically, just start with the right signal from the start)

I've been reading more. Here and other sites, and came up with what you already said. The older tpi systems use a 2000 ppm vss and the newer ones used a 4000 ppm. The T56 sensor output is 4000ppm, correct?
I read something about square wave and ac output too, but I can't remember what was what there at the moment.

If the t56 vss is 4000ppm and I have the later model 730 ECM that uses a 4000ppm signal, what would be wrong with just changing the plugin on the harness to fit the T56 vss? (if all the square wave/ac output stuff is compatable).

I'll check see which ecm I have in a minute.

Tuned Performance

iTrader: (92)

My bad than I thought the t56 was a magnetic pulse 4k ppm and could just got to pin b9 the vss ground and pin b10 the signal input of the 730 ecm.
I was wrong sorry

http://www.skulte.com/T56.html

TFS355S10

iTrader: (2)

Oh my, Now you're talking way beyond my relm.... LOL I'll check out that link though.

Tuned Performance

iTrader: (92)

It says you need to buy tha $90 gizmo or post a ad in the classifieds here. I have seen used ones go for 50-60 bucks.

TFS355S10

iTrader: (2)

LOL. I see.
I found one on ebay for 75 bucks, but for the life of me I can't understand why everybody seems to want to use the wrong vss and the convert the signal to what they need.
I just look at things from a simpler point of view. I'm from the V8 S10 world and things like this just make me think the guys that do things that way would weld on a couple cylinders to a V6 engine to get a V8, instead of using a V8 to begin with.... LOL

Tuned Performance

iTrader: (92)

Instead of machine and fab work there is no other factory vss for this transmission the fix is electrical. I managed to find you the solution in the second post and give you a headache as well.

TFS355S10

iTrader: (2)

I'll take the machine and fab route almost every time myself. LOL

Like the guy that designed and built the cable drive for the t56's. I'm sure there was a few that told him there's no way. LOL

I've found 2 vss's that will physically fit in the T56 and I've only looked at 3 transmissions. I have a vss out of a NV4500, (92-96 full size chevy 5 speed), in my t56 right now. I doubt if it will like the t56's reluctor ring, but it does fit in the trans and plugs into my TPI wiring. A S10 T5 5 spped vss will also fit in the the t56. Whether they are compatable with the TPI ecm I don't know. (Yet)

My ECM is #16198262. I bought it and the TPI wiring from a guy on ebay a few years ago when I started this conversion. It is "supposed" to be "reprogrammed" or whatever for non emission 305tpi. He marked it as prom code AXYD on the outside of the case. At the time he had good feedback and had sold quite a few of these, but I've since lost track of his seller name and info.

Tuned Performance

iTrader: (92)

The 1227730 has 2 reman superseded numbers 16198262 and 16196344 all the same ecm.


http://www.s10-v8.com/Pages/Parts_T5...luct_ring.html

Yet another option, with this you can use your drac and the the memcal can easly be reprogramed to accept the optical 2k signal from the drac to pin c6 of the 730 ecm.

The iac follower is slightly different from the automatic tune you have and a manual transmission tune. I bet your engine doesn't like you when your slowing down or come to a stop.

TFS355S10

iTrader: (2)

Well, that's good. It does say remanufactured on it. I'm pretty sure I have the original ECM out of the Trans Am I got the motor out of also, but can't remember for sure. LOL

TFS355S10

iTrader: (2)

And I have an old JTR book around here somewhere too, but haven't been able to find it either.... LOL

That's the info I need! Thank you for doin the legwork for me! LOL

Tuned Performance

iTrader: (92)

More than one way to skin a cat on this thread lol

TFS355S10

iTrader: (2)

LOL, Yep.

Dyno Don

iTrader: (7)

I think you are missing the whole point here, that ECM will never understand the signal that comes from a reluctor ring.
It needs a different signal, a magnetic signal generator driven with gears is the only way without going to the SGi box.

https://www.thirdgen.org/forums/engi...ble-drive.html

After this mod you can then get a aftermarket signal generator that fits on the cable drive that will feed the correct signal.
Painless has them.
http://www.painlessperformance.com/w...rchField=60116

TFS355S10

iTrader: (2)

You're probably right. I'm missing the point of why and how it needs to be done. LOL

What I'm not understanding is the need to convert to something the tpi never had to begin with. When it had a 700r4 trans behind it, it had a vss in the side of the transmission.
Granted it was a MAF system and I have a speed density wiring harness now, but either way it would have a vss in the trans, (and a reluctor wheel of some sort).
Speed density should have a buffer in the ECM, correct? MAF systems had the buffer in the instrument cluster as far as I know.

Am I right here; for a TPI system I need a vss and a buffer, (assuming it's still in the original car and all the other normal sensors)

Just because I've changed to a different transmission with a different size hole in the side of it is no reason to convert to a cable drive that I have no use for. (Other than to drive a vss) For almost 500 bucks it will do without a vss of any kind. If I'm spending that much it will go toward a wiring harness for an LS swap. The 6.0 is in the shop waiting anyway. LOL

There has to be a vss that can be adapted to this transmission. There were tpi cars with manual transmissions, (T5). The vss/reluctor wheel in those cars should work for me? because I'm pretty sure they will fit in the T56. (One out a a T5 equipped S10 truck will fit the T56)

Edit, just state my opinion... lol I'd rather build a whole new transmission tailhousing as add more electronics. Electronics fail, machine work stays. lol

Dyno Don

iTrader: (7)

The VSS in the 700R4 and the T-5 produces a sine wave, the reluctor in a late model 4L60E and the T-56 produces a square wave, they are not compatible with each other.
You have to have gears to drive a sine wave signal. The magnetic generator is on a line with the output shaft and reluctor. So you can't bolt in a gear drive to match up.
If you do the mod in that picture, you can install the gears and pulse generator from a T-5.

TFS355S10

iTrader: (2)

Ok, I got the sine wave/square wave differences. And I just went out and pulled the vss out of the original 700r. Like you said, it is gear driven. That clears things up for me somewhat.

Not sure what you're rfering to here. The T56 vss/reluctor?

Dyno Don

iTrader: (7)

Picture it this way, the VSS on the T-56 is just a magnet, a reluctor wheel is behind it, as it turns the signal is created.
When you look in the hole where it is on the case, you can see the reluctor wheel.
So, you can't put a gear driven device in there. It has to be below the shaft.
The Painless device (magnetic generator) is driven by a speedo output. The two wires from it go to the ECM.

Dyno Don

iTrader: (7)

Here is one installed from a T-5

Notice it is below the shaft.

TFS355S10

iTrader: (2)

Yep, I looked at that part too.

It's a good thing you guys are patient. That pic and the "It has to be below the shaft" part finally soaked through why I cant use the original vss hole. Duh. LOL

More questions, is that a stock T5 vss in that pic? The one from painless has the external cable drive, so I'm guessing the one in the pic is stock.
Does it use stock gears? If so I'm running 4.10 gears, I don't think any 3rd gen camaro came with gears anywhere near that low. Do they even make a gear set to match a 4.10 rearend gear?

So what it amounts to is,
1. I'm back to a $500 cable drive conversion that I really have no use for other than to get a signal to the ecm.
2. $325 for a guy to drill a hole and use the stock T5 vss to supply signal to the tpi ecm.
Both of which more than likely my speedo still won't work because it's a newer system than the tpi and will need a different signal yet. Or because it's in a truck and needs a drac...
3. The Dakota digital SGI-5 box.

4. The JTR 40 tooth reluctor wheel, my drac and the the memcal reprogramed to accept the optical 2k signal from the drac to pin c6 of the 730 ecm (I copied what Tuned Performance posted earlier here... LOL And I can build a 40 tooth reluctor wheel just like JTR did)

Or 5. Go postal on a bunch of electronic engineers and make the world a better place for a generation or two. LOL

I'm pretty sure I could do the tailshaft housing modifcations myself to use the T5 or cable drive setup if I had to. I don't have a mill, but I do have a lathe and it can work as a mill with the right attachment. not quite as fancy as a mill, but if it gets the job done... LOL

From what I see of the JTR 40 tooth reluctor wheel it is nothing more than the T56 reluctor turned down to a "hub" and the 40 tooth ring out of whatever transmission bored out, then the 2 pieces pressed together. I can do that.

If I have these options kinda sorta right, which one would you guys do?

Dyno Don

iTrader: (7)

It is a stock T-5 VSS, but they are disco and hard to find.

It does take gears and drilling and pressing parts together the right ratio
can be achieved. (4.10 I think it's 7 & 24) The end looks just like a speedo drive where it goes in the hole. Very hard to find gears anymore. You can get the 7 tooth drive but the 19-24 tooth driven gears are gone.
The early 350 turbo trans used the small gears with a plastic stem, cut off the stem drill a hole on the gear and press in the half moon shape piece from a different gear that fits the VSS.

This is why we all say "get the SGi box".

TFS355S10

iTrader: (2)

I've got a whole collection of speedo gears, but, guess what, pretty sure they are all the bigger style ones. LOL (Later model th350/early 700r I think)

Would a TBI T5 Camaro use the same vss as a TPI car? A friend of mine has a TBI/T5 car.

TFS355S10

iTrader: (2)

LOL. damnit.

Which brings up another question. If I was to get the SGI-5 box, it will make the right signal for the tpi ecm. Do you have any idea if it will also supply the correct signal to make my cruise and/or speedo work? (Can't remember if I mentioned this in the thread, but all this is in a 98 Sonoma truck.) The speedo is still a secondary concern, but I'm not gonna complain if it works. LOL Cruise would be sweet though.

I see it has 4 outputs. Do all the outputs send the same ppm signal or can each one send a different ppm signal?

TFS355S10

iTrader: (2)

Reviving my dead horse so I can beat on it some more... LOL

I now have the SGI-5.

Refreshing my own memory here, let me know if I got this right.

T56 stock vss = 17ppr Square wave (Pulse per revolution)

TPI needs 4000ppm Sine wave (Pulse per mile)

Stock Sonoma vss = 40ppr signal (Converted to something else through a drac?? I have no idea yet LOL)


For the time being I'm just going be using the stock T56 vss and reluctor ring and convert through the SGI-5 to make the motor run.

So I'll need to figure my ppr to ppm to get an idea where to start, correct? (Revolutions per mile? X 17 = ppm?)

26in tall tire, 4.10:1 gears = 776 revs per mile? (Approximately. I didn't take into account the loaded radius of the tire)

776 revs per mile x 17ppr = 13192 ppm Am I on the right track here?

Then 13192ppm needs to be converted through the SGI-5 to 4000ppm signal for the tpi?

Later, when I get a 40t reluctor ring, I'll swap to that and a vss from a 2wd S10 manual transmission. Which will hopefully make my speedo and cruise work.
http://www.s10-v8.com/Pages/Parts_T5...luct_ring.html
I'll have to redo the math at that point.