TBI Fuel Injection/Dakota Digital Question (1 Viewer)

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I recently took over the resto of a 1971 fj40 , original engine, which was rebuilt and fitted with TBI fuel injection. Transmission is a 1978 4 speed, with a 1974 TC. Also installed is a Dakota SGI-5E speed interface. Initially I thought that the SGI was a required part of the TBI. After a little research, I think that it may have been put there to satisfy emissions requirements in its previous State. I live in MA, and there are currently no such requirements for older vehicles. If I just remove the transfer case interface, and unplug it, will that cause any issues with the TBI and/or ECU ? The two reasons I am thinking of doing it is that 1, it is hard up against the parking brake cable, and 2, I am not sure if this interface would properly seal, as I have read there can be an issue with TC oil leaking. That being said, are there any benefits to me just keeping it in place ? I have the transmission hump off at the moment, so I want to address it now.

Thank you
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I'll give you my opinion, but there are those on Mud who might disagree. A Vehicle Speed Sensor (VSS) does several things, but most importantly it works with the 02 sensor to control idle functions, which is just about everything your engine does below 5 mph. Most people using the spedo cable driven VSS use a custom 8" to 10" long spedo cable to bring the VSS out from behind the parking brake. Looks to me like you have the 4 pulse VSS (since Stealth Conversions discontinued the 2 pulse VSS that you actually need), sooooo previous owner used the SGI-5 to cut the 4 pulses down to 2, ??? I maybe wrong, but that's what it smells like to me. The other choice may be that you are using a spedo cable driven VSS to drive a Dakota Digital speedometer, and the speedometer has been adjusted to give the ECU a 2 pulse signal, but in that case why would you need the SGI-5 ???
 
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thank you very much. No Dakota Digital, nor do I plan on getting one. Any idea where I can get a custom Speedo cable ?
 
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If you don't have a Dakota Digital speedometer, then 1. how are you presently driving your stock speedometer ??, 2. what is the piece between your transfer-case and the 4 pulse VSS you have now ??, and 3. how are you handling the difference between 2 pulse square wave DC and 4 pulse sine wave AC ????
 
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I have not driven this vehicle. This vehicle was partially restored out West somewhere, then purchased locally. The local purchaser had it about 3 months, no further action, then sold it to me as is. I do not know what the piece is between the VSS and TC, but I do not like the looks of it. The rig did come with a bunch of parts, including a new speedometer cable. Regarding your 2 pulse vs 4 pulse question, that is beyond my current knowledge. Based on what I have said, do you think that using the extension alone will work ?

While I have the transmission hump off, and your well respected attention, can I please bother you with two more questions. One of the wires on the back up light is broken off. Assuming it still otherwise functional, what are you thoughts on soldering another wire to the stub that is left, or should I just chuck it.

also,

there is another sensor on this 78 transmission, which I beleive is for a 4th gear emissions output of some sort. As mentioned earlier, being in MA, I was thinking of leaving it alone.

thank you again.
 
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If you don't have a Dakota Digital speedometer, then 1. how are you presently driving your stock speedometer ??, 2. what is the piece between your transfer-case and the 4 pulse VSS you have now ??, and 3. how are you handling the difference between 2 pulse square wave DC and 4 pulse sine wave AC ????


I went by at lunch to take another look. The VSS is connected to the TC with a stewart warner 666f reducer. Your thoughts please.

thank you

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Ok, your set-up is starting to get above my pay grade (or imagination), but let me take a guess. Your TBI needs a 2 pulse signal, Stealth Conversions 2 pulse VSS was yellow plastic, their 4 pulse VSS was black plastic, so I think you have a 4 pulse VSS. Then possibly the Stewart Warner 666f piece may have been a device to cut your rpm in half so that 4 rpm was producing a 2 rpm signal ???- - -but if that is close to the truth, why would you have needed the SGI-5 to do the same thing ???.
 
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The SW part is just a speedo correction device. The bottom number .97xx is the ratio.

thank you. Perhaps the SW is there in lieu of the extension cable to get the VSS away from the TC. Now I just have to figure out why the VSS is there in the first place. I like what Mr. Downey says, but when I checked with AFI they said that I should not use a VSS. thanks again
 
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It sounds like your best bet now is to contact the company who's TBI injection is installed and they should be able to fill in the blanks why certain parts may have been used and if they can be removed.
 

pjohnson

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The SW device may have been used as an adapter of sorts. The drive pin is different between Toyota and domestic.

As Jim mentioned, to VSS or not has many opinions. You could run without it and add it back if you have problems.
 
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I believe guys on mud who do not use a vss with their tbi may be satisfied with their rig because it still runs( so they will say you don’t need a vss), they just don’t know how nice the drivability should be, i.e. they don’t know what they are missing.
 
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Thank you mr Downey. I’m going to remove the sw reducer and use a short cable. As was kindly pointed out by another member, the reducer hardly makes a change in the revs, so I think it was there for spacing.

I have a November/73 tc. Would you recommend/ does it take the oil seal gasket that ?
 

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