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Thread: Super Rich

  1. #1
    Fuel Injected! jim_in_dorris's Avatar
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    Super Rich

    No, not my bank account. The story so far;---- 87 4x4 1/2 ton 3.73 31" tires 305 with 700R4. I just had to put a new fuel pump in the truck, and since I am eventually planning a build, I upgraded the fuel pump to an EP377. I also installed my modded TBI with a homemade adjustable fuel pressure regulator, a TBI spacer, and the salad bowl mod. Then I had a short in the fuel pressure feed wire which I fixed by cutting out the shorted section and adding in a new wire. It started running really bad, and I figured too much fuel pressure. Sunday I went in to my son's work and we looked at it. 40 psi! not good, so I pulled the adjustable regulator and turned it down. It would pause at 12 psi for about 1/2 second then hit 40 psi again. I think I didn't do the regulator right when I built it, so today I put the stock fixed fuel pressure regulator back on. When I took it out for a test run, it would not go closed loop. I had a bunch of codes set. I pulled the battery cable and cleared them, then went for another run. It did go closed loop for a while, but at 7 minutes I hit an INT of 43!!! At about 11 minutes, it gets an O2 sensor rich code and goes open loop. I know that it is really rich, but would like somebody to go over the log to see if I am missing something.
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  2. #2
    Fuel Injected! JeepsAndGuns's Avatar
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    Did you check the fuel pressure after you reinstalled the stock regulator? Did you check and make sure the return line is ok and not stopped up or pinched?
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  3. #3
    Fuel Injected! jim_in_dorris's Avatar
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    Jeeps, I have to take it back into my sons work to check the fuel pressure, that means a Sunday. I havent checked the return line yet, guess I should. Thanks.
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  4. #4
    EFI GearHead ! EagleMark's Avatar
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    Your not missing anything! Your RICH! Most of the BLM histor4y is 108, that is max low/take out. Something is wrong and I'd but pressure is way high.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  5. #5
    Fuel Injected! jim_in_dorris's Avatar
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    Mark, can 350 injectors in a 305 cause that, or do you think there is something else wrong. I will try the return line Thursday to see if that is the problem, just not sure how I will do that yet.
    Return line is passenger side correct? Maybe I can blow thru it to see if it is plugged.
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  6. #6
    Fuel Injected! jim_in_dorris's Avatar
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    Well, tried blowing through the return line, i think it is restricted. I am going to try an experiment. I have a junked astro van I am pulling parts from. I am going to cut off the return line, and put a piece of fuel hose on in leading to a gas can. If that helps, I know what my problem is, I will just need to figure out where.
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  7. #7
    EFI GearHead ! EagleMark's Avatar
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    That's what I do. Run a line from return into a gas can and check pressure. That return should blow through with gas cap off, even on for short time. The early tanks I've seen have a one way valve in. Some are just a hole...

    Sorry I missed your other question about injectors... not sure? Did some calculations and there should be some room, but your maxed at low 108 BLM.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  8. #8
    Fuel Injected! jim_in_dorris's Avatar
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    Well, I went down to the Astro Van and the lines were cut off, so no go. I will try the JY to get a fitting. I didn't take the gas cap off, I will try that too. Still going to be sunday before I can check pressure unless we can borrow the fuel pressure tester and bring it home friday. That way I can test it saturday. I wish this truck would idle in closed loop, that would help. Guess I am going to have to get a bin burned with the tuning mods done. I think that OIT's engineering dept may have some prom burners, if I can get permission to use one. I do know someone in the software dept there that I am working with on developing a class.
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  9. #9
    EFI GearHead ! EagleMark's Avatar
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    You get the mechanics squared away then we can do some data from your chip, you can make adjustments etc... I told you I'd send you a chip. I know it's not as good as burning yourself but at least you can get started.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  10. #10
    Fuel Injected! jim_in_dorris's Avatar
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    Yeah, the mechanicals are first, I am just thinking ahead. I will test fuel pressure connected to the return line, then with the adapter so I can rule that out. I can go from there. I hope it's not too hard to find. I have a slight kink right at the throttle body, but unless the fuel pump is just too big, it shouldn't be that.
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  11. #11
    EFI GearHead ! EagleMark's Avatar
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    I've run that pump many times and not had over pressure issues. So if your over pressure and can't adjust down it has got to be a return side flow issue?

    With 350 injectors in your stock 305 you really only need 13 PSI...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  12. #12
    Fuel Injected! jim_in_dorris's Avatar
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    Roger that, I will report back after I get some more testing done.
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  13. #13
    Fuel Injected! jim_in_dorris's Avatar
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    Okay, I had a chance to check fuel pressure today. It's over 40 PSI. I removed the return line, and ran a test line to a gas can. 12.5~13 psi. I now know the it is the return line. Now to find the restriction. PROGRESS!!!!!!
    Square body stepsides forever!!!

  14. #14
    Fuel Injected! jim_in_dorris's Avatar
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    I took the return line loose at the first joint, down by the tranny, and then hooked it back up at the throttle body. 12 psi. no love. I guess I drop the tank next.
    Square body stepsides forever!!!

  15. #15
    EFI GearHead ! EagleMark's Avatar
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    Darn! So you do have a blockage somewhere between there and tank? That sucks...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

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