VSS for TBI conversion (1 Viewer)

Texican

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cardinal fang said:
How did you dig up that web site Butch? Great detail. Fabricate a speed sensor....cool :eek: :cheers:

He sells his TBI adapter on Ebay once and while, and I found his site thru that, got lots of good free info.
Butch
 
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What would be the interest in an electronic unit to take any 4-pulse per rev down to a 2-pulse per rev?

I can make that a wire-in logic unit if there's enough of a demand for it. I am considering using the downey VSS to drive an Auto Meter speedometer and a 1989 GM 5.7 ECM that needs a 2-pulse per rev.

I had a JTR Speed Sensor and it destroyed itself because I didn't install the extension cable. I think that setup is pretty generic looking and cheesy anyway. If you're eliminating the OEM speedometer the JTR speed sensor is kinda cheap looking.
 
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I don't know about the need for 4 to 2, but I (and others I have talked to) have an Autometer VSS that is 16 pulse. It would be nice to be able to convert that to the GM 2 pulse for the TBI instead of replacing it with a JTR VSS.
 
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I can do a divide by 8 as well. Here's a proof of concept video. The blinking lights represent the pulse output of the VSS. I could build a unit that will divide by 2, 4, 6, and 8. depending on what wire you hook up. I was also thinking about some sort of selector switch. We'll see how the design develops.

https://www.facebook.com/photo.php?v=10151608985473241&set=vb.584968240

What VSS do you have? Do you have a part number? I was considering going with an autometer speedo. This device could have plenty of applications since the Toyota VSS is usually 4ppr and many GMs are 2 or 4 as well.

Let me know what you think...
 
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I can do a divide by 8 as well. Here's a proof of concept video. The blinking lights represent the pulse output of the VSS. I could build a unit that will divide by 2, 4, 6, and 8. depending on what wire you hook up. I was also thinking about some sort of selector switch. We'll see how the design develops.

https://www.facebook.com/photo.php?v=10151608985473241&set=vb.584968240

What VSS do you have? Do you have a part number? I was considering going with an autometer speedo. This device could have plenty of applications since the Toyota VSS is usually 4ppr and many GMs are 2 or 4 as well.

Let me know what you think...

What sort of pricing are you looking at? I need to feed both a 16 pulse electronic speedo and the 2-pulse input on a TBI ECM.

Haven't purchased it yet but planning on using the Classic Instruments 16 pulse VSS (part number SN16m, which has 22mm x 1.5 threads).

Sent from my iPhone using IH8MUD
 
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Interesting ideas! Keep them coming! I think that the PCB would cost around $5-8 then the components would be no more than $10 so the overall cost of the materials would not exceed $15-25. This isn't the kind of thing I'd want to retire on, so I would put the shipped price no more than $30.

Let me build one and see how reasonable it is. In my application i just need a divide by two so I may need some field testers. I'll let you guys know how it goes.

I'm going to build a very rudimentary one for my testing. Lets talk about what would be reasonable features. I like the idea of switches and a single output, but that may drive the cost up.

Maybe screw terminals on the PCB so you can just screw the output(s) into the appropriate port on the terminal and if you need more than one then they're all available?
 
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I like that idea. I have other boxes (like an intermittent wiper box I found) that had a terminal with holes you put the wire in then a set screw on top to grab the wire. Worked well.

Your price range would be great. I know I'd buy one. Much better solution than buying a VSS from JTR and then having to reprogram my speedo.

I would offer to test for you, but I won't be starting my TBI install until the end of the year and the VSS on my chip was turned off for now. I do want to re-enable it later when I get good at the programming/tuning.

Maybe screw terminals on the PCB so you can just screw the output(s) into the appropriate port on the terminal and if you need more than one then they're all available?
 
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That's great feedback, thank you! I will work to incorporate screw terminals in the initial design. I may make a basic one that has all of the wires soldiered on there as an option. If you know someone who is in the same situation let them know. I'd like to get some feedback as to how/if the device works.

Oh yeah, you definitely want the VSS signal in the system. I know it runs without it, but there are things that just don't work correctly. If you're running a GM Automatic trans your converter lockup will be weird if it works at all. EGR won't work and the purge solenoid on the EVAP system will be disabled or will run at inappropriate times depending on how it was removed from the computer. If you're running a manual trans you still have emissions to contend with, especially if you have smog checks.

I know that land cruiser people are anti emissions, I'm no exception. I have replaced the 20 some-odd feet of vacuum tubes on my 2F, and it didn't help at all. That's why I picked up the Weber 38/38... :) BUUUUT on the TBI the emissions actually do work, and they're pretty simple when they do. They definitely don't reduce the power output of the engine either.

I'm really disappointed that JTR is the only reasonable source for the 2-pulse VSS that has metric fittings. I bought one, I think it's crappy. The design sucks, the quality is reasonable until it breaks because it doesn't fit. (I've tried to contact JTR, and they're barely helpful IF they return your call/email) Its just unclean looking. Putting one more component in the speedometer cable is a bad idea, and it doesn't do anything for those of us that would rather have an aftermarket speedometer. Speedometer shops are pretty much impossible to find anymore (even in Indianapolis). Everything is digital now days. I think this could end up being a popular solution that provides options for the GM EFI swap people. Who knows it could have other applications that we haven't even thought of yet.
 
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I have a 4l60, but wired it to lock without a computer. I don't have any smog on the engine now. No EGR, no nothing. As far as I can tell VSS will let the engine run a little better with some improved performance, switch on highway cruise, etc. I do want it enabled at some point.

Oh yeah, you definitely want the VSS signal in the system. I know it runs without it, but there are things that just don't work correctly. If you're running a GM Automatic trans your converter lockup will be weird if it works at all. EGR won't work and the purge solenoid on the EVAP system will be disabled or will run at inappropriate times depending on how it was removed from the computer. If you're running a manual trans you still have emissions to contend with, especially if you have smog checks.
 
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Oh dang. Yeah, if you have no smog equipment then it may not be much of an advantage. I just yanked the entire engine lock, stock, and barrel, and threw it all in my FJ. I figured hundreds of engineers at GM figured something out so I just left it all alone. Besides, one of my primary reasons for doing EFI was emissions related. I don't mind polluting less. It's pretty easy to pollute less than a 2F though.
 
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I have an '83 engine so am going to mod it for TBI. I do have my eyes open for a good engine with TBI (all pieces) and would be happy to swap it. They are few and far between, though.
 
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That's great feedback, thank you! I will work to incorporate screw terminals in the initial design. I may make a basic one that has all of the wires soldiered on there as an option. If you know someone who is in the same situation let them know. I'd like to get some feedback as to how/if the device works.

Oh yeah, you definitely want the VSS signal in the system. I know it runs without it, but there are things that just don't work correctly. If you're running a GM Automatic trans your converter lockup will be weird if it works at all. EGR won't work and the purge solenoid on the EVAP system will be disabled or will run at inappropriate times depending on how it was removed from the computer. If you're running a manual trans you still have emissions to contend with, especially if you have smog checks.

I know that land cruiser people are anti emissions, I'm no exception. I have replaced the 20 some-odd feet of vacuum tubes on my 2F, and it didn't help at all. That's why I picked up the Weber 38/38... :) BUUUUT on the TBI the emissions actually do work, and they're pretty simple when they do. They definitely don't reduce the power output of the engine either.

I'm really disappointed that JTR is the only reasonable source for the 2-pulse VSS that has metric fittings. I bought one, I think it's crappy. The design sucks, the quality is reasonable until it breaks because it doesn't fit. (I've tried to contact JTR, and they're barely helpful IF they return your call/email) Its just unclean looking. Putting one more component in the speedometer cable is a bad idea, and it doesn't do anything for those of us that would rather have an aftermarket speedometer. Speedometer shops are pretty much impossible to find anymore (even in Indianapolis). Everything is digital now days. I think this could end up being a popular solution that provides options for the GM EFI swap people. Who knows it could have other applications that we haven't even thought of yet.


I know this is an old post but did you ever get the VSS made and if so will it work in line with the factory cable and factory gauges.....CA smog is ridiculous and I can't get it past without one. I have a 78 FJ40, 1990 350 TBI, 700R with the stock FJ transfer case. Thanks again.
 
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ALL Chevy TBI's need a 2 pulse VSS, Landcruiser 6 cylinder with TBI or Chevota!!!!! The VSS works with the 02 Sensor to control idle functions (everything below about 5 mph). Without the VSS you'll have rougher idle (no automatic choke), many times will act like a cold engine on a cold morning, and engine can die/shut off when you come up to a red light/stop sign- - - just plain poor drivability without a VSS!!!!!
 
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Every thing I have read says the same thing. VSS is better than no VSS. I have an Autometer 16 pulse VSS and have asked several times in different places if it would matter if the VSS gave 2 or 16 pulses per rev. I am wondering is someone has done it and what the results are. Hate to spend another $100 on a VSS from JTR.
 
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Dakota Digital has a splitter (SGI-5 I think) that will split a signal down, but I don't think it will split all the way down from 16 to 2 pulses- - - check it out?????
 
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Thanks Jim. I am looking at it now. Looks like it might work. Price is about the same as buying a new VSS. Looks like I am going to have to spend money either way.


Dakota Digital has a splitter (SGI-5 I think) that will split a signal down, but I don't think it will split all the way down from 16 to 2 pulses- - - check it out?????
 
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Sorry guys. I haven't been on this forum in a long time. I still haven't built this device. I just deal with the check engine light every once in a while. If there's still interest in the splitter I'll draw up a schematic. it was pretty simple. I think it's still attached to my breadboard. Let me know if you want the drawing...
shoot me an email @@@

Mike@madorbit.com
 

Josie'sLandCruiser

Stop calling it a "FJ."
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Hi all,

I have run GM TBI on the 2F in my FJ40 both with, and without, a vehicle speed sensor (VSS).

I agree with Jim (aka Downey) that the VSS is needed. Yes, the system will work without it, but the TBI runs smoother with a VSS.

I used the speedometer mounted unit from Jags That Run. The easiest way to install this unit is when the t-case mounted parking brake is dis-assembled (so you can rotate the p-brake backing plate for clearance.) Since I did not have the p-brake apart I installed it using the speedometer extension cable from Advance Adapters.

Regards,

Alan
 

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