using 1988 dash with 1995 sensors

[MuddiGGEr25]

Does anyone know off hand if the reference signals/resistance are the same for the CTS on the 454 TBI and the temp sensor on small block tbi/6.2's? I am trying to figure out where to tap in so i can use the existing dash gauges

It appears that the oil pressure switch (on the 1995) is also the sensor/sending unit according to the wiring diagram, but not sure if the gauge will short out or read properly if i wire that up. or if it will affect the PCM any by having an additional sensor "grounding" the signal

[Irish_Alley]

the signal would be the same (gm used that sensor up till 2009 maybe even longer).

the OPS was used from 90 to 99. dont know if the reading would be the same. i think they would cause in my 91 crew cab i have the same sending unit (or switch) and my gauges are pretty much the same as the 88s
http://forum.73-87chevytrucks.com/smforum/index.php?topic=31456.0

[big_al273]

i have a 91 gauge cluster from a parts truck and as far as i can tell the gauges are all the same as previous years with the exception of the fully electronic speedometer

[MuddiGGEr25]

So i should be able to tap into the CTS for my temp gauge on the dash? I thought my 350 TBI had a seperate sender for the dash signal?? (it was a 1987 block/PCM  in  a 1988 body)

I will tap into the OPS once i superglue it back up (hopefully that will work, just the plastic housing snapped, nothing inside appears to be damaged) it looks to be a magnetic pickup of some kind that reads off the OP and converts it to a resistance.

[Irish_Alley]

theres two sensors for the tbi units, yes. one goes to the ecm (on the intake) the one in the head goes to the gauge/light the color code will be the same for the gauges.

not sure why you want to tap into the wire. it should be a simple plug and play. a few post up i also attached a link to the cluster wiring harness diagram

[MuddiGGEr25]

I want to tap into the wire because i am mating up the 1995 TBI 454 into the 1988 V20 suburban that used to have the 6.2L, and pretty much nothing is preexisting, so im matching up wires from scratch because i was in too much of a hurry to label anything.

[Irish_Alley]

no need to tap the wires into place. the cts for the gauge will be the same plug, wire and sensor. it will be a plug and play. dont know if you need to extend the wire but that might be your only problem.

does your 88 not have any wires in it now?

[MuddiGGEr25]

I sold the 6.2L and TH400 to a kid that was building his first truck for work/school so i cut the entire harness about 16" from where the loom comes out of the firewall to make his life a little easier. its not a big deal to me because it means i dont have all the extra wires still laying around the engine bay, so once i get around to ziptieing the 1995 harness it should look pretty decent, all i need to do is waterproof the PCM since im leaving it on the passenger fender next to the heater box


Its not going to be the most beautiful setup but as long as it runs and drives and gets us to TN safely at the end of the week, thats all i care about

[Irish_Alley]

ok, i understand the issue now. one good thing most the wires in the firewall junction box arnt needed to start and run the truck. another good thing is i know for our trucks gm kept the same wire colors for the same sensors. like the CTS is always green oil should be blue and etcetera. make understand the wire harness much easier.  i kind of had to do this when i did my cummins swap. most the wires i didnt have to touch and i want to say i only had to cut the wires not being used.