post #1 of Old 08-28-2011, 12:53 PM Thread Starter
brandolabs
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2013 JK Wrangler 
 
Join Date: Aug 2011
Location: Minneapolis
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anti-drainback valve question

Looking for some expertise. So for the last month or so my YJ has been slow to start (3-5sec crank). connections are solid, new redtop optima (6 months), and a new starter (4 months). Through all of my forum searching it seems that my problem is most likely my anti-drainback valve leaking or losing pressure so that when I start my jeep the pump has to pump the fuel before it can fire blah blah.

Question is, how much of a pain in the butt is it to replace and is it worth doing before I sell. Selling because i've got a squirrel 4 cyl and I need more power. any responses are much appreciated, thanks guys

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post #2 of Old 08-28-2011, 01:01 PM
Desert_Rampage
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1991 XJ Cherokee 
 
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I have this same issue. Where is said drainback valve? I have access to ALLDATA but not at the moment.

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post #3 of Old 08-28-2011, 06:58 PM
Desert_Rampage
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bump
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post #4 of Old 08-28-2011, 08:18 PM
deathtrap
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1993 YJ Wrangler 
 
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The drain back check valve is in the in tank fuel pump, you gotta replace the pump. If your fuel pres. is ok
once it is running I doubt it will cause low power just long crank time.
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post #5 of Old 08-28-2011, 08:20 PM
Desert_Rampage
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What if it's a carb'd engine? Wouldn't it be the filter itself acting as a valve?
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post #6 of Old 08-28-2011, 08:26 PM
deathtrap
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1993 YJ Wrangler 
 
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Carb engines dont realy need one because fuel is stored in the carbs float bowl when the engine is not running.
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post #7 of Old 08-28-2011, 08:31 PM
Desert_Rampage
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True True. Idk, I have the 4.2 w/ 32/36 Weber and mine takes ages to crank after sitting for any length of time. Kinda irritating.
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post #8 of Old 08-29-2011, 09:53 AM
Que89YJ
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1989 YJ Wrangler 
 
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Your bowl might be evaporating off the full if it's hot and a while inbetween starts.
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post #9 of Old 08-29-2011, 12:28 PM
vadslram
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1990 YJ Wrangler 
 
Join Date: Jan 2006
Location: VA Beach
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Mine did that too. Carbed w/MC2100. It was kind of annoying. I even popped the top of the carb and the fuel had drained right to the needle float.
I switched out the fuel filter and that fixed it. I guess at least on mine the anti drainback is in the filter.
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post #10 of Old 08-29-2011, 01:24 PM
Alabamaranger
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1990 YJ Wrangler 
 
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I was wondering to. Mine is a 4,2 with a MC2150 carb. It turns over more when sitting a few days. I run the fuel filter with the fuel return hose.

My son has the same carb on his Ford Ranger with no fuel return filter. His starts up a lot more quickly. So I guess it's psooible for the fuel to go back to the tank and drained up to the needle valve inside the carb. With the fuel filter return, after shut off, there should be no fuel pressure at the carb since it's vented back to the tank on the re.

I learned that the fuel filter return line, had to be at the 12:00 position, It was to keep fuel flowing to prevent line lock up from heat, and to releive the pressure from the fuel pump when it's not needed as much (idle).

Most Fords do not have return lines. So I am wondering if you have a carter or motorcraft, that the fuel return can be eleminated?

90 YJ, 4.2 with 2150 carb 4.0 Head and headers, Nutter with TFI and MSD. 1" BL, 2.5" spring lift, 33", Goodrich KM Mud Tires. Dana 30 w Aussie, Ford 8.8 w LS. 9000lb HF Winch.
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