a friend of mine wants to swap a carbureted 383 into a 96 chevy pickup with the port injected 4.3l vortec v6. is there any way to do this and retain the function of his factory gauges? i think he's only got speedo & fuel level. he also wants to replace the factory t-5 with a tremec 5-speed.
RETAINING ELECTRONIC GAUGES
- Thread starter MEGABU
- Start date
Far as I know the sensors & everything should be the same. Just cross-reference the sensors from the 4.3 to the sbc... should be the same... and if they are, just use them in the new motor 
that makes sense. i think he's really more concerned about his speedo than anything else though. i believe those are electronic, tied into the ecm, and he's getting rid of all that stuff, so how does he keep his stock speedo with an aftermarket transmission & carbed motor? is an lt1 swap compatible with his factory chassis harness, say, if he had to stick with an efi setup? these questions just spawn more questions!
The LT1 isn't going to be compatible with his factory harness. It's going to use a completely different harness and PCM.
It being a 96, it's OBDII so the speedo gets its reading from the PCM. That means the input from the trans goes to the PCM then the PCM sends the signal to the dash. You might check with Dakota Digital to see if they make an adapter to bypass the PCM, but if they do it's expensive.
If the new 5-speed trans has a mechanical speedo output, you can get a converter that will send an electronic signal to the PCM, so he could keep the PCM, hook up the other sensors he wanted to use (if any) and then find someone with a GM Tech-II programmer to turn off the other functions and SES light for the PCM so that he could retain the speedometer functionality.
That's about the only way I can think to make this happen.
It being a 96, it's OBDII so the speedo gets its reading from the PCM. That means the input from the trans goes to the PCM then the PCM sends the signal to the dash. You might check with Dakota Digital to see if they make an adapter to bypass the PCM, but if they do it's expensive.
If the new 5-speed trans has a mechanical speedo output, you can get a converter that will send an electronic signal to the PCM, so he could keep the PCM, hook up the other sensors he wanted to use (if any) and then find someone with a GM Tech-II programmer to turn off the other functions and SES light for the PCM so that he could retain the speedometer functionality.
That's about the only way I can think to make this happen.
I'd keep portions of the stock wiring along with the ecm (just pull the SES light bulb :lol, I don't think it'd be too hard to put a reluctor wheel on the output shaft of a Tremec, though they oughta make them to work with a vss. I'm looking at a diagram of the 4.3 controls in my Haynes manual right now. Looks like the gauges are tied in somewhat to the ecm.
Pressure sender/switch:
, I don't think it'd be too hard to put a reluctor wheel on the output shaft of a Tremec, though they oughta make them to work with a vss. I'm looking at a diagram of the 4.3 controls in my Haynes manual right now. Looks like the gauges are tied in somewhat to the ecm.- The temp. sensor doesn't even send a signal to the temperature gauge, it goes through the ecm.
- The oil pressure sender is actually a regular pressure sending unit and a switch that enables the fuel pump if the pcm doesn't turn it on for some reason. I'd keep this as cheap insurance (wire a relay to kill the pump w/o pressure) if you lose oil pressure, unless he's already switched to a mechanical pump and isn't just using a regulator to keep pressure down. If he's not using the OEM pump, sending unit, relay, etc. you can use an older style sending unit, just make sure the ohm range is the same so the gauge reads correctly. It still uses a tan wire like older sending units, the other two are orange and gray (org=hot in run/start - 20A fuse, gray=fuel pump prime circuit, part of the 'underhood fuse/relay center').
- If he's sticking with the stock sending unit, the fuel gauge is fine.
- It shows the tach being driven off of the module in the distributor, I don't know if this would be the same as the tach terminal in an HEI cap. If not, the manual also shows a white wire coming off of the alternator (adjacent to the brown wire), but it says 'diesel only'. I'm guessing you could pick up an alternator plug with this white wire and wire that to the tach (if the truck has one, I think all the newer ones did )
Pressure sender/switch:
Also, are you talking about a TKO 5-speed? If so, he's in luck
http://www.ttcautomotive.com/English/news/20news.asp
http://www.ttcautomotive.com/English/news/20news.asp
thanks doober, you kick ayoss! i'm sending by buddy that link right now(it's his dad's truck). awesome!
Interesting that the temp sensor runs through the PCM.
In know in my 1996 Formula, there was a temp sensor in the water pump that went to the PCM. But there was also a temp sensor in the driver's side head that ran the gauge in the dash.
In know in my 1996 Formula, there was a temp sensor in the water pump that went to the PCM. But there was also a temp sensor in the driver's side head that ran the gauge in the dash.
Doober said:
I'd done some more reading after posting this, found the correct info about the oil pressure, and corrected it now (going through my old posts
). Sorry if someone read this & got mixed up. I may do this for power to the coil since I'm still running a mechanical pump.Similar threads
