Site Sponsors & Vendors
Page 1 of 2 12 LastLast
Results 1 to 10 of 15

Thread: 1995 chevy c3500 454. runs rich

  1. #1
    Junior Member
    Join Date
    Mar 2009
    Posts
    12
    Post Thanks / Like

    Default 1995 chevy c3500 454. runs rich

    i got a 95 c3500 with a 454 in it.. manual trans 196,000 miles. truck runs rich. code 13 and 45. scantool show 1101mv on o2 sensor. fuel pressure is 32. spec is 26-32 for the 454... 350 is 9-13psi. (i looked it up, i thought tbi only need 9-13.. not the 454) i went to napa and bought a fuel pressure regulator kit... spring was very weak compared to the one i took out. only had 18psi with new kit.. truck would stumble... put old spring back in. truck acts up in closed loop.. bogs down as computer is taking the fuel away... obd I. LT fuel is 84. tried new o2 sensor, and computer.. no help... replaced fuel pump due to 38-40 psi... now 32psi... truck runs good when o2 sensor is unpluged, or in open loop. any ideas?... anybody?

  2. #2
    Junior Member
    Join Date
    Mar 2009
    Posts
    12
    Post Thanks / Like

    Default

    also good spray on injectors, and no dripping. key on, and injectors don't leak down

  3. #3
    LOST BUT NEVER FORGOTTEN GRRRR8's Avatar
    Join Date
    Aug 2008
    Location
    Sugar Land Texas
    Posts
    15,917
    Post Thanks / Like

    Default

    Check coolant temp sensor. If it looks green on the outside change it. Also when the truck is cold it will usually read - 20 degrees for the ECT.
    2008 Liquid Red Pontiac G8 Sport/Premium - Adams Polishes - American Racing Headers - ARP - BMR Fabrication - Circle D Specialties - COMP Cams - Crazy Paul - Dynojet - Earl's - Flowmaster - Fuel Air Spark Technology - G2 - GFORCE 1320 - Greg Weld - HP Tuners - JBA - Lingenfelter - Maverick Man Carbon - Metco Motorsports Solutions - Mickey Thompson - M&H - Mike Norris Motorsports - NGK - Pace Performance - Pedders USA - Powerbond - PSI - Russell - SBX Performance - SJM Manufacturing - SPOHN Performance - Tony Mamo - Vararam - Vector Motorsports - Wretched Motorsports - 470 RWHP 427 TQ - Engine Tune By Patrick G

  4. #4
    Junior Member
    Join Date
    Mar 2009
    Posts
    12
    Post Thanks / Like

    Default

    yeah, already checked that... was reading 198 when hot... i was hoping it would show -40 degrees, meaning open in ect sensor or wiring problem.... thanks.

  5. #5
    LOST BUT NEVER FORGOTTEN GRRRR8's Avatar
    Join Date
    Aug 2008
    Location
    Sugar Land Texas
    Posts
    15,917
    Post Thanks / Like

    Default

    The MAP sensor vac line is not broken/split? Did you check the TBI base gasket? If fuel is good, ECT is good, now its focus on things that force an engine rich like vac leaks.
    2008 Liquid Red Pontiac G8 Sport/Premium - Adams Polishes - American Racing Headers - ARP - BMR Fabrication - Circle D Specialties - COMP Cams - Crazy Paul - Dynojet - Earl's - Flowmaster - Fuel Air Spark Technology - G2 - GFORCE 1320 - Greg Weld - HP Tuners - JBA - Lingenfelter - Maverick Man Carbon - Metco Motorsports Solutions - Mickey Thompson - M&H - Mike Norris Motorsports - NGK - Pace Performance - Pedders USA - Powerbond - PSI - Russell - SBX Performance - SJM Manufacturing - SPOHN Performance - Tony Mamo - Vararam - Vector Motorsports - Wretched Motorsports - 470 RWHP 427 TQ - Engine Tune By Patrick G

  6. #6
    Junior Member
    Join Date
    Mar 2009
    Posts
    12
    Post Thanks / Like

    Default

    on the 454 the map sensor has 1 vacuum line that splits into 2 lines and both of them go to the back of the intake. i sprayed carb cleaner all over the intake hoping to find a vacuum leak.. no luck, no raise in rpms..

  7. #7
    LOST BUT NEVER FORGOTTEN GRRRR8's Avatar
    Join Date
    Aug 2008
    Location
    Sugar Land Texas
    Posts
    15,917
    Post Thanks / Like

    Default

    Does it chug while its running?
    2008 Liquid Red Pontiac G8 Sport/Premium - Adams Polishes - American Racing Headers - ARP - BMR Fabrication - Circle D Specialties - COMP Cams - Crazy Paul - Dynojet - Earl's - Flowmaster - Fuel Air Spark Technology - G2 - GFORCE 1320 - Greg Weld - HP Tuners - JBA - Lingenfelter - Maverick Man Carbon - Metco Motorsports Solutions - Mickey Thompson - M&H - Mike Norris Motorsports - NGK - Pace Performance - Pedders USA - Powerbond - PSI - Russell - SBX Performance - SJM Manufacturing - SPOHN Performance - Tony Mamo - Vararam - Vector Motorsports - Wretched Motorsports - 470 RWHP 427 TQ - Engine Tune By Patrick G

  8. #8
    Junior Member
    Join Date
    Mar 2009
    Posts
    12
    Post Thanks / Like

    Default

    only under a load in closed loop. runs fine then no power, goes from 55-30 then kicks in... the computer takes the fuel away. it can idle in closed loop, smells rich and shows 1101mv on o2 sensor... unplug o2 sensor, still runs rich, but doesn't bog down... i guess because with the o2 sensor unpluged it stays in open loop, and the computer doesn't take fuel away.

  9. #9
    LOST BUT NEVER FORGOTTEN GRRRR8's Avatar
    Join Date
    Aug 2008
    Location
    Sugar Land Texas
    Posts
    15,917
    Post Thanks / Like

    Default

    See what the engine vac is to make sure it doesnt have a bad cat on it, if it has one. If it doesnt, see what engine vac is hot/cold.
    2008 Liquid Red Pontiac G8 Sport/Premium - Adams Polishes - American Racing Headers - ARP - BMR Fabrication - Circle D Specialties - COMP Cams - Crazy Paul - Dynojet - Earl's - Flowmaster - Fuel Air Spark Technology - G2 - GFORCE 1320 - Greg Weld - HP Tuners - JBA - Lingenfelter - Maverick Man Carbon - Metco Motorsports Solutions - Mickey Thompson - M&H - Mike Norris Motorsports - NGK - Pace Performance - Pedders USA - Powerbond - PSI - Russell - SBX Performance - SJM Manufacturing - SPOHN Performance - Tony Mamo - Vararam - Vector Motorsports - Wretched Motorsports - 470 RWHP 427 TQ - Engine Tune By Patrick G

  10. #10
    Junior Member
    Join Date
    Mar 2009
    Posts
    12
    Post Thanks / Like

    Default

    sounds good, i'll put a vacuum gauge on it and get back with you tomorrow.

Posting Permissions

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