FiTech Fuel Injection

Discussion in 'Tech Discussion' started by Bigtime53, Jun 7, 2018.

  1. Bigtime53

    Bigtime53 Junior Member

    Age:
    64
    Posts:
    18
    Likes Received:
    2
    Joined:
    Dec 14, 2015
    Location:
    Poteau,Oklahoma
    First Name:
    Vaughn
    Truck Year:
    1977
    Truck Model:
    1500
    Engine Size:
    350
    Well I got my A/C all lined out now after getting all of the extra oil out of the system but now I have a new problem. I have a 77 GMC with a 350 and I bought the FiTech fuel injection for it. I put it on last fall and I do not drive this truck much since the total rebuild of it but have been some now to get the a/c working properly. The truck is vapor locking and it really ticks me off. I followed the instructions to the letter and kept all of the fuel lines away from where there should not be a problem with heat. The only thing that is close to any heat is the command center which is on the drivers side of the radiator and not right up against it. My question is has anyone else have one of the systems and are you having this problem? What should I do to stop this?
     
  2. 4WDKC

    4WDKC Full Access Member

    Posts:
    1,457
    Likes Received:
    553
    Joined:
    Jan 27, 2016
    Location:
    Illinois
    First Name:
    Kacy
    Truck Year:
    1987
    Truck Model:
    V10
    Engine Size:
    350
    Are you sure its vapor lock and not a vacuum on the tank issue?
     
  3. crazy4offroad

    crazy4offroad Service Bullshit Filter Soon

    Age:
    46
    Posts:
    8,308
    Likes Received:
    616
    Joined:
    Jul 30, 2010
    Location:
    West BY-GOD Virginia
    First Name:
    Curt
    Truck Year:
    1977
    Truck Model:
    One-Ton K-10
    Engine Size:
    350/TH350/NP205
    Does the command center need a return line? If so dont use your vent line as a return. You may have to get a newer float assembly that has fuel, return and vent lines on the top. If it doesn't need a return line it sounds like your vent line is plugged, crimped or otherwise not working properly.
     
    1987 GMC Jimmy likes this.
  4. Bigtime53

    Bigtime53 Junior Member

    Age:
    64
    Posts:
    18
    Likes Received:
    2
    Joined:
    Dec 14, 2015
    Location:
    Poteau,Oklahoma
    First Name:
    Vaughn
    Truck Year:
    1977
    Truck Model:
    1500
    Engine Size:
    350
    Well I don't think that is the problem. I have put close to 200 miles on this truck since I installed this setup and have not had a problem until it has been getting close to 100 everyday and then this started happening.
     
  5. Bigtime53

    Bigtime53 Junior Member

    Age:
    64
    Posts:
    18
    Likes Received:
    2
    Joined:
    Dec 14, 2015
    Location:
    Poteau,Oklahoma
    First Name:
    Vaughn
    Truck Year:
    1977
    Truck Model:
    1500
    Engine Size:
    350
    I called fitech and they told me to use my orginal return line and that is what I have done. A friend of mine bought the same setup for his truck and his is vapor locking also. We both put the command center in the same location and I am wondering if it is getting to hot being by the radiator. Both trucks did not have a problem until it has got hot here and started running the a/c. I am going to put some insulation around it [command center] and try that and if that does not work then I will have to do something else.
     
    crazy4offroad likes this.
  6. crazy4offroad

    crazy4offroad Service Bullshit Filter Soon

    Age:
    46
    Posts:
    8,308
    Likes Received:
    616
    Joined:
    Jul 30, 2010
    Location:
    West BY-GOD Virginia
    First Name:
    Curt
    Truck Year:
    1977
    Truck Model:
    One-Ton K-10
    Engine Size:
    350/TH350/NP205
    I dont think you're the first to complain of this with the command center. I think it runs out of gas in the little tank and the pump sucks air. Likely why many go with the in-tank fuel pump option.
     
    1987 GMC Jimmy likes this.
  7. 1987 GMC Jimmy

    1987 GMC Jimmy Full Access Member

    Age:
    21
    Posts:
    3,902
    Likes Received:
    852
    Joined:
    Jan 23, 2016
    Location:
    New Orleans, LA
    First Name:
    Jesse
    Truck Year:
    1987
    Truck Model:
    V1500 Jimmy
    Engine Size:
    350
    I’ve used this example before, but when GM kept getting complaint after complaint on P30 based motorhomes vapor locking, they put a fuel pump in the tank AND kept the mechanical one, which cured it. Of course, those had to have an external regulator on the frame rail, and yours is internally regulated. I’d consider doing an ‘87 tank or tanks depending on your setup, an ‘87 sender with that Walbro 255 (?) pump, and a standard five pin relay to control the pump properly. I understand that this is not a simple solution, and if this is not 100% the problem, you would have wasted your time and money, but this is the right way to go about any fuel delivery setup that’s not carbureted.
     
  8. 77 K20

    77 K20 Full Access Member

    Posts:
    1,406
    Likes Received:
    151
    Joined:
    Nov 9, 2012
    Location:
    Montana
    First Name:
    Mike
    Truck Year:
    1977
    Truck Model:
    K20 3" lift
    Engine Size:
    HT383 fuel injected
    Kinda an apples or oranges thing- but I have something similar. I have the Edelbrock E-street EFI and it has the fuel sump kit also.

    It is setup with the old mechanical fuel pump on the engine and now all it does if feed/fill up the Edelbrock fuel sump which is mounted on the passenger side of the radiator (where the old radiator overflow tank used to be). I've never had an issue with vapor lock and have run it at 90 degree days crawling up the side of a mountain to a fire lookout.

    Do you still run the mechanical fuel pump also?
     
  9. crazy4offroad

    crazy4offroad Service Bullshit Filter Soon

    Age:
    46
    Posts:
    8,308
    Likes Received:
    616
    Joined:
    Jul 30, 2010
    Location:
    West BY-GOD Virginia
    First Name:
    Curt
    Truck Year:
    1977
    Truck Model:
    One-Ton K-10
    Engine Size:
    350/TH350/NP205
    I think he has to. It may be possible he needs a mechanical fuel pump that puts out more volume.
     
  10. 4WDKC

    4WDKC Full Access Member

    Posts:
    1,457
    Likes Received:
    553
    Joined:
    Jan 27, 2016
    Location:
    Illinois
    First Name:
    Kacy
    Truck Year:
    1987
    Truck Model:
    V10
    Engine Size:
    350
    can you route cool air to the system as a test?
     
  11. Bigtime53

    Bigtime53 Junior Member

    Age:
    64
    Posts:
    18
    Likes Received:
    2
    Joined:
    Dec 14, 2015
    Location:
    Poteau,Oklahoma
    First Name:
    Vaughn
    Truck Year:
    1977
    Truck Model:
    1500
    Engine Size:
    350
    Ok i googled fitech vapor locking and watched a video of how to fix the problem. Long story short seems like the pump that is in the command center gets the fuel to hot and the return line only sends vapor back to the fuel tank. They say to take the float out and where the filter is inside of the command center for the return line take it out and that way fuel will circulate and keep it cool and stop the vapor lock. That is what I will do and so far they say it fixes ti.
     
    crazy4offroad likes this.
  12. bluex

    bluex Full Access Member

    Posts:
    981
    Likes Received:
    345
    Joined:
    May 9, 2013
    Location:
    Spartanburg SC
    First Name:
    Paul
    Truck Year:
    1978
    Truck Model:
    C15
    Engine Size:
    350
    Glad you found that, I was just about to post that's what I've seen a lot of people with the command center do.
     
  13. Brett77

    Brett77 Junior Member

    Posts:
    4
    Likes Received:
    2
    Joined:
    Feb 12, 2018
    Location:
    Glendale AZ
    First Name:
    Brett
    Truck Year:
    1977
    Truck Model:
    c10
    Engine Size:
    502 stroker
    I have been told there are problems with the command center. Fitech rep at a show shared that info. Other than that how does the FI-Tech work?
     
  14. 77 K20

    77 K20 Full Access Member

    Posts:
    1,406
    Likes Received:
    151
    Joined:
    Nov 9, 2012
    Location:
    Montana
    First Name:
    Mike
    Truck Year:
    1977
    Truck Model:
    K20 3" lift
    Engine Size:
    HT383 fuel injected
    Yes, I'm interested to know how it works also. With the Edelbrock system it like to surge (idle starts going up and down by 300-400 RPM) from time to time. But won't do it when it is in gear and idling.

    Getting annoying- Especially when I'm idling using my air compressor to air up my tires after an off road trip.
     
  15. Bigtime53

    Bigtime53 Junior Member

    Age:
    64
    Posts:
    18
    Likes Received:
    2
    Joined:
    Dec 14, 2015
    Location:
    Poteau,Oklahoma
    First Name:
    Vaughn
    Truck Year:
    1977
    Truck Model:
    1500
    Engine Size:
    350
    Mine ran great all winter when I did drive it only to start having this vapor locking problem. I have been happy with it so far.
     

Share This Page