1996 chevy Tahoe put new motor in and gauges are off

redux 1. see next post, 5.3L , 8COPS, 8 injectors, present and sea of sensors sure EFI.
we learned this.
5.3L engine.
not told if Passkey there.IMMO, it can not be IGNORED or hacked if there, RPO tells if it is there.
RPO codes tell what was on the car sold day 1, RPM is GMs name for AS _BUILT
RPO tells if car is IMMO opted. and matters first.

symptoms so far:
cranks ok
starts and runs and dies fast my guess 3seconds fast but not told
if dies, use right foot to prevent the stall, and post her if it did or not.

NO SCAN tool used is a very bad thing, on any modern car.
buy one , rent, lease, barrow one, or have car savvy friend scan yours.
I bet the tool tells you what fails

1: bad fuses. all must be checked on modern cars as lots of communications bus, can fail fuse blown.
2: engine compression pass.
3: scans show X,y, bad, tell what it finds, and we tell you what to check next.
eg: P0341, cmp dead. or ckp dead or error that says , they are out of sync,(timed wrong means0
4: fuel pressure not at spec cranked, , using gauge per SM
5: not reading the SM here.
https://eautorepair.net/Marketing/Default.asp


RPO? google how to read GM RPO codes and where found on car body.
glove box, console box lid, trunk lid, spare tire lid or drivers door jam, edge 3D bar code for RPO and GM app that reads it fast. and easy .

then see if IMMO codes is in list
AUO =Remote Function Actuation - Keyless Entry – Domestic
VATS, PassKey, and PassLock

DTC B3055, pass key failure DTC errors or B3935?
and more car cranks but alternator is dead and after it runs battery voltage is too low.
and sets a DTC for weak battery as it fails.
use a charger to keep battery fully charged and test ALT For dead. 13v to 15vdc is good running later when it does.

Well it could be the sending unit for the gauge.
But odds are the oil pump or engine bearings are worn out.
As the engine warms up, the metal spaces expand and the oil gets thinner. The oil pressure drops some under normal conditions, but not more than 10 or 15psi. Normal idle pressure with the engine warmed up is probably 25psi.
You could check oil pressure with a mechanical gauge to make sure its not the sending unit.
Once the oil pressure starts staying below 20psi for long periods you'll start hearing noises.

Yes it may be the wires are shorting or its actually the problem with instrument cluster.
Also get the vehicle scanned for any error codes stored in computer this will confirm whether is short circuit issue or actual problem:------
I suggest you few help links with accurate solutions to refer/go through:----Click the link below:------

Battery and brake Warning lights on Dash
http://alltypesofpartsreplacing.blogspot.com/2012/10/battery-and-brake-warning-lights-on-dash.html
--------------2002 Ford Windstar: Brake Warning Light ON dash? http://schematicsdiagram.blogspot.in/2012/06/2002-ford-windstar-brake-warning-light.html
-------------ABS & Brake warning lights remains steady on dash? http://schematicsdiagram.blogspot.com/2011/12/abs-brake-warning-lights-remains-steady.html
-----------Chevrolet Tahoe Hood open warning on dash and alarm sounds? http://schematicsdiagram.blogspot.com/2011/12/chevrolet-tahoe-hood-open-warning-on.html
-----------2005 Chevy Impala: Service Vehicle Soon Warning Light? http://whoisbyme.blogspot.in/2012/06/2005-chevy-impala-service-vehicle-soon.html -------------- Malfunction Indicator Light ON http://whoisbyme.blogspot.in/2012/06/malfunction-indicator-light-on.html
-----------Car Runs Fine But Check Engine light is ON?

http://whatisbyme.blogspot.in/2012/05/car-runs-fine-but-check-engine-light-is.html

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Check engine light with codes P2195 and P2197?

http://howtobyme.blogspot.in/2012/01/check-engine-light-with-codes-p2195-and.html

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How to Read Codes from Check Engine Light? http://schematicsdiagram.blogspot.com/2011/12/how-to-read-codes-from-check-engine.html
-------------These will help.Thanks.

did you install the oil pressure switch origional to the tahoe? The tahoe uses a low oil pressure shutdown, instead of an inertia switch to shut off the fuel pump in the event of an accident. If the pressure circuit does not close within 3 seconds after the engine starts the fuel pump shuts off. This is in case the truck is on its side or upside down the pump will shut off.

You need to have the computer checked for for trouble codes. Most of your local Auto Parts stores will check them for free.

Change the engine oil or top it up to the specified level if the oil is still good and not burnt. After such conditions if the engine oil level is low, it would be advisable to change it completely. Also check if water pump is able to circulate the water properly(see on removing the radiator cap while the engine is running). Clean all plugs as added safety and try...sodeep

You may need to do a code scan,this will reset the computer and reset any codes if the brake problem has been taken care of.Autozone Shucks/Kragen/O'Reilly's will do this for free.

check the coolant temp sensor

http://www.autozone.com/addVehicleId,2314001/initialAction,repairGuide/shopping/repairGuide.htm?pageId=0900c1528008ef16

disconnect battery and reconnect. If you have a problem that the computer is sensing, the light will reappear. At that point you must fix the problem. If your car seems to be running ok it could be something minor. Check all sensor connections under the hood