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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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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?
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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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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.
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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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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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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.
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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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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.
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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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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...
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Roger that, I will report back after I get some more testing done.
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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!!!!!!
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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.
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Darn! So you do have a blockage somewhere between there and tank? That sucks...