Hey fella's. Swapping an LS3 into the bird and not sure how you guys have handled the oil pressure and temp? Are you able to splice from the ls1 wires? or do you need to tap in the old oil pressure sending unit from the old engine? How about temp unit? Any ideas on where to tap that in?
Thanks,
Nate

 

most of this has been covered but here is what I know, heard and have done.


oil psi. just use the ls1 sender,


temp. '98 I belive? is the only year you can use for a sender to work on the thirdgen guages. as it has the 3 pin allowing for the guage output.

I turned my thirdgen sender down, rethreaded it to I think off the top of my head 12mm???? and installed in on the pass head. didn't have to but since I had a lath it was cheap and I knew it would work.


a simple search should net some more known info. this is all off of my head

 

anyone have a 98 one laying around? ive got a 02 motor.

 

I dont know if I covered that in the sticky or not but I drilled out the pass head and tapped it for the stock third gen temp sender. Oil i drilled out and tapped the little added on piece that comes plugged just above the oil filter. Its basically the same dia needed to tap 1/8" NPT and from there you can thread in a mech or electric oil press gauge. Or you can remove the stock LSx oil pressure sender at the rear of the block behind the intake and use an equus adapter kit to hook up your oil sender there. FWIW the stock LSx oil sender does nothing for the PCM it wont trigger any codes if you unhook it.

 

Does the stock ls1 oil sensor not work with our gauges? Why not just use it's tan wire output on c220?

 

IIRC no it does not but I eliminated my stock third gen gauge to put a new tach in ( oil pressure inside the tach face in my stocker ) so it was never a concern to me to really figure this out. In short I dont think it works but i cant really recall why... and its possible maybe Im wrong altogether and it does work.

Try it?

 

it works, I have mine wired like that..

If you go by the specs from gm the ohms are wayyyyyyy off but I took the sender and compared the readings at differant psi and found them to be very close.

 

How did you hook up the ls1 sender to the factory oil pres gauge?

 

When I did my swap I just used a 98? Coolant sensor and the stock oil sensor. My gauges are all stock tpi stuff. All work great btw

 

3rd gens used a single wire to drive the oil pressure gauge. Its the same for the LS1 sender. 98s had an oddball with an external ground, so use a 99+ PN if possible. Later 3rd gens had the FP relay bypass circuit ran through the OPSU. Ignore the ORN and GRY or TAN/WHT wires. Only the tan wire drives the gauges. If you have the older style sender that is a simple spade terminal, cut it off and crimp a delphi 150 series female sealed terminal on the wire, then snap the connector on. They're super common in JYs and found on nearly all 85+ GM vehicles if you want a used piece. Alternatively you can drill out a busted LSx sender or the bypass port above the oil filter and mount your old 3rd gen sender