Search results

  1. W

    Help needed ASAP. 99 4.8 in 94 c1500

    I changed the TPS Got new harness today. Had to modify couple of plugs. One was for the MAF had a 3 pin on harness needed 5 pin. And the o2 sensors where square needed flat ones. Got those done today and old one back out. Will install and keep posted
  2. W

    Help needed ASAP. 99 4.8 in 94 c1500

    When you unplug MAF it idle hunts up and down a few times when you try to throttle up it dies. I greatly appreciate the suggestions. Another set of eyes (viewpoint) is greatly appreciated
  3. W

    Help needed ASAP. 99 4.8 in 94 c1500

    I cant datalog until new harness gets here Friday. The customer bought a donor car and it was running. The person he initially hired of course made this swap 1000 times more difficult. If anyone else has suggestions I'm open ears.
  4. W

    Help needed ASAP. 99 4.8 in 94 c1500

    June 20th- New harness ordered. However still having issue as explained here is a video
  5. W

    Help needed ASAP. 99 4.8 in 94 c1500

    I am waiting on customer to authorize the new harness. It was already highly suggested when the truck was dropped off and I took a look at it. Still trying to figure out why it's cutting out. I dont believe it's a harness issue since it idles and revs up 500 or so rpm before it cuts out. It...
  6. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Update June 20th: Fuel Pressure is now 60PSI (changed to a better fuel pump) Still revs up and then just cuts out. I'm at a loss on what it could be at this point. I have done 100s of custom swaps but normally dont go behind other people because of this. I will upload a video but it literally...
  7. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Update June 18th. Rechecked and took apart harness. Now have power to all sensors like it should. Issue Fuel Pressure. I'm getting 40PSI at start/idle and throttle which I believe is reason for engine cutting out. If I recall should be 55/60PSI at idle and not drop sub 40s under throttle.
  8. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Sorry if I wasnt clear. I meant that is where they cut the OBD off. I ordered the connector just hasnt arrived yet
  9. W

    Help needed ASAP. 99 4.8 in 94 c1500

    I ordered the OBD2 Connector and pins but they are having huge shipping delays
  10. W

    Help needed ASAP. 99 4.8 in 94 c1500

    It has no OBD port at all. Just the connector in front still waiting on shipment for the stuff to wire in my own.
  11. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Update: went through and fixed all the **** ups. Got the butt connectors on to give the 2 orange wires constant power and the 2 PCM pink wires that typically recieve power from Key fixed to get power. Now have power to the IAC and TPS sensor. Made a plate to block off egr Idle is now decent...
  12. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Yes this isnt my 1st hack job swap that I've been stuck with. I pulled out the harness and am going to start eliminating the unneeded stuff and then repair from there. I'm not diminishing the value of the others harnesses, but I cant justify paying $350 and sending the harness in for this...
  13. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Yeah I couldn't find one so I'm going to have to rewire it and retrace all the wires
  14. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Here are some more pictures to help paint the picture.
  15. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Above are some of my nightmare fun. Does anyone have a diagram of the grounding locations in the engine bay and out of harness? (My Drive with Alldata took a crap and new one isnt here yet.)
  16. W

    Help needed ASAP. 99 4.8 in 94 c1500

  17. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Oh lord you have no idea all the stuff I have to fix. I'll upload some pics
  18. W

    Help needed ASAP. 99 4.8 in 94 c1500

    I am considering looking for a custom or factory harness. Anyone know of anyone?
  19. W

    Help needed ASAP. 99 4.8 in 94 c1500

    Thanks for the "kind words". Sadly this is probably the best of the wiring so you can only imagine the rest
  20. W

    Help needed ASAP. 99 4.8 in 94 c1500

    I had the computer flashed and it will start and idle. However when I attempt to press the gas pedal it revs up a couple 100 RPM then falls flat on its face. I can unplug the throttle position sensor (brand new) and same thing happens. It's almost if the ECU isnt communicating with sensors to...
  21. W

    4.8L Vortec decent idle but NO power

    Unplugged throttle position sensor no change so replaced it with a known working one still the same issue. It's almost as if the computer isnt making adjustments to fuel and or spark when you press throttle. If you hold throttle to flow it revs up 200-300 rpms then just cuts out drops back to...
  22. W

    4.8L Vortec decent idle but NO power

    I unplugged EGR and it made no difference: No better or worse literally no change. I repaired the purge valve. My thoughts: 1. Some issue with EGR or broken EGR 2. Problem with ECM wiring 3. Throttle position sensor 4. Injector(s) 5. Problem with coil packs? (Has new plugs and wires) Other...
  23. W

    4.8L Vortec decent idle but NO power

    So another update. Truck basically revs up to around 1500RPM then just cuts out and drops back to idle even if you continue to press gas pedal. Feels almost like a rev limiter or fuel cut. Thoughts? Suggestions?
  24. W

    4.8L Vortec decent idle but NO power

    Here are some things I've found while diagnosing.
  25. W

    4.8L Vortec decent idle but NO power

    Quick backstory: Customer Swapped 4.8 vortec to replace 4.3L in a 94 C1500. Brought to me in pieces. Computer has been flashed all unnecessary stuff removed (including theft) When you attempt to push throttle no matter if under load or not. Motor does not rev very well and sputters and cuts...

Latest posts

Members online

Total: 1,144 (members: 49, guests: 1,095)

Forum statistics

Threads
64,744
Messages
1,399,844
Members
52,357
Latest member
m_howard19

Share this page

Top