GM Truck Club
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 3 of 3
  1. #1

    Default 1990 chevy 1500 w/t

    someone please help i have a 1990 w/t chevy 1500 pu,4.3 tbi m/t , it all started one day and the truck started to hesitate and never been the same since and i have changed almost every part on the system,it keeps coming up code 45 its a rich code,but the truck put me broke lol,I have put these parts new,rebuilt computer,o2 sensor,plugs,wires,new distributor,coil,map sensor,tps sensor,iac sensor,and the fuel pressure is 13 psi at all times,3 sets of injectors,cat converter,computer chip,Im so fustrated i dont know what to do someone please help.Buy the way when the service engine light comes on the truck runs excellent all help is appreciated

  2. #2
    Legend unplugged's Avatar
    Join Date
    Sep 2006
    High Deserts of SoCal

    Default OBDI code 45

    Related info:

    Code 45
    4 flashes, pause, 5 flashes
    Oxygen sensor voltage was over 0.75 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. Rich exhaust. Check the evaporative charcoal canister and its components for the presence of fuel.
    Possible Causes of an EVAP System Failure
    * Cracks, leaks or disconnected hoses in the fuel vapor lines, components, plastic connectors or lines * Charcoal canister is damaged or saturated with fuel (due to EVAP vent valve problems) * EVAP service port is leaking * Fuel filler cap (gas cap) is loose or missing * PCM has failed
    EVAP Purge Conditions
    The PCM purges the canister under these conditions: * After the engine has reached operating temperature * At wide open or part throttle (as long as the engine is not overheated) * The engine can be in open or closed loop Fuel Control in a purge event
    MIL Operation, How to Clear History Trouble Codes
    If the EVAP Monitor detects a fault during a drive cycle, it will set a pending code and store the current vehicle conditions in Freeze Frame. If it detects the fault for two consecutive trips, the MIL is activated and a code is set. The MIL will remain on for more than one trip, but will go out if conditions that caused the EVAP Monitor to fail do not reappear on three consecutive trips. After the MIL is off, the trouble code will be erased after 40 consecutive trips if the fault does not reappear.
    There is no way to happiness....happiness is the way.:yipi:  _vXMYypuKMJFw671uF2ZPhjez_j-atRmcjM2zQKpQi1JSsB75/burb1.JPG
    High Desert SoCal
    93 K1500 burb (personal) 350 AT 3" Lift 250K+
    02 Honda Civic LX
    Looking for a 1990's Miata for an engine swap

  3. #3


    If the EGR valve isn't working properly it will cause a rich condition to occur. I replaced the distributor, plug wires, and plugs. I finally gave up and took it to the dealer. Now my truck runs real good after the EGR valve was replaced.

Similar Threads

  1. 1990 Chevy 1500 headlight problem
    By man2god in forum GM Electrical Tech
    Replies: 2
    Last: 11-12-2011, 08:09 PM
  2. 1990 Chevy 1500 Driving me INSANE
    By bonehead79 in forum Chevy C/K Truck Forum
    Replies: 4
    Last: 11-29-2009, 07:44 PM
  3. Chevrolet : C/K Pickup 1500 454 SS CHEVY 1990 CHEVY 454 SS 1500 TRUCK
    By ChevyFan in forum Chevy Trucks For Sale eBay
    Replies: 0
    Last: 08-13-2009, 03:50 AM
  4. Chevrolet : C/K Pickup 1500 454 SS CHEVY 1990 CHEVY 454 SS 1500 TRUCK
    By ChevyFan in forum Chevy Trucks For Sale eBay
    Replies: 0
    Last: 07-27-2009, 12:40 AM
  5. Replies: 0
    Last: 06-08-2009, 07:20 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts