Robt.

1992 Jeep YJ Wrangler Fuel Filter Leaks—a Pressure Problem?

8 posts in this topic

I'm new here. Is this where I can ask a question?  If so, my fuel filter (new) keeps leaking. (excessive fuel pressure?) I'm wondering if the fuel regulator is faulty? I've used new clamps, super tight, after a couple of days, it leaks again.

 

Robt.

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Could be many things. Did you just suddenly see leaks? Recent changes? Fuel lines dry out. OEM filter? Any custom stuff in fuel system?

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Silly question. Is the filter oriented the right flow direction? 2 or single line system?

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This is the place for questions, Robt.  Welcome to the forums!  You could post at our Jeep Wrangler forum, however, this will do.  There are some generic, useful concerns here...

 

RareCJ8 posed a basic concern, that the fuel filter must be installed with the flow in the correct direction.  It must also be the correct filter for your YJ Wrangler's fuel system, MPI/EFI requires a fuel filter with a specific pressure rating.  If the filter is aftermarket, make sure the part number is a direct replacement for the Mopar OE filter.

 

Your fuel injection system should operate near a maximum of 39 PSI.  This is with the vacuum line disconnected to the fuel regulator at the injection rail and the engine idling.  Connect the vacuum line, and pressure with the engine idling should be 31 PSI.  The difference is for cranking pressure while starting the engine.  Maximum pressure at the injection rail, under any circumstances, should always be less than 45 PSI. 

 

Warning: The maximum dead headed pressure from your 1992 YJ fuel pump is around 75 PSI and should not be tested for more than two seconds.  Use extreme care with gasoline under this high pressure, wear protective goggles and keep gasoline away from hot spots!

 

The regulator on your two-pipe MPI/EFI system returns excess fuel to the tank.  If there is a restriction in the return line, fuel pressure would be high, and if the regulator is defective, that could cause a restriction.  I'd be more inclined to think return line restriction; these regulators seldom stick shut, more often they hang open.

 

A pressure check of the fuel pressure can be readily done with the proper gauge at the Schrader valve on the fuel rail (at the engine).  This valve is easy to spot on the fuel rail, it looks like a metal valve stem for a wheel/tire.  You might want to check the pressure to see if that could be causing your fuel leak.

 

I copied a view of the fuel lines and filter for your '92 YJ Wrangler.  You can review the illustrations and parts to see whether something is out of sorts with your system.  The hoses must be in top shape and have high pressure EFI gasoline rating. 

 

Clamps should be EFI grade.  I like the European style with the overlapping band and a screw/nut tightening provision.  You can specify these clamps at NAPA and elsewhere, they are commonly known as EFI fuel hose grade.  Your fuel hoses at the filter should be rated well in excess of 50 PSI, the higher rating, the safer. 

 

Here is a PDF with illustrations and part numbers for your fuel lines and filter.  You can zoom-in for details and Mopar part numbers.  Your model is a Wrangler "YJ":

 

1992 YJ Wrangler Fuel Filter and Lines Diagram.pdf

 

Try the fuel pressure test at the fuel rail.  Make sure your fuel filter and lines to the regulator are not restricted and that fuel flows readily.  (Please observe my warning about high pressure and gasoline!)...Make sure the return line is not restricted and that it dumps excess fuel into the tank.

 

You can get an inexpensive fuel test gauge kit from Harbor Freight and others.  If you plan to make a career out of fuel pressure testing, you'll want a better grade test gauge.

 

Moses

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A efi pressure gauge is a priceless diagnostic tool and rides in the jeep all the time. Now with dash mounted gauge is even greater insurance. For the OP wonder if anything was done or happened, replaced, etc. What motivated the filter change? Am happy I went with the spin on filter system. Life is easier

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Wow! I wasn't expecting any replies this quick. Thanks a million guys. I am glad that I found this forum. I will check the system today. Thank you very much Moses for the time and effort you put into the answer. I'll post my results asap.

Robt.

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I need to give more data on the reasons I'm having fuel pressure problems. I recently installed a new fuel filter as I just rebuilt the engine. I dropped the fuel tank down to check hose connections, electrical connections, etc. I think, since I read Moses' reply, that I may have a restricted return hose. I also cut a hole in the floor over the tank to gain access to the pump and lines so I won't have to drop the tank in the future. Some earlier jeeps had an access hole. When I put the tank back in place, I may have caught the return line between the floor and the tank. I'll check that this morning. I modified this jeep considerably.

 

I used to own a 1951 CJ 3A. I wish I had never sold it. I love the simplicity of the early jeeps. On my 92 Wrangler, I removed the dash and all of the gauges, everything, and went back with a 26 ga metal dash with 4 round gauges, oil, volt meter, temp and fuel and speedo. Now, I can leave it outside without the top and if it rains here in Florida, it won't hurt anything.  I did all of this two years ago before I rebuilt the engine.  I removed the top, let down the windshield, installed a 12 thousand pound winch, built a new grille using 1/2 & 1 in flatbar and installed half-doors and low back seats. I painted the jeep olive drab. Now, I can put the top back on in a few minutes for inclement weather if I need it. This jeep is an attention getter. Thanks again everybody and especially Moses. 

 

Update:  Moses and everybody, I found the problem to my excessive pressure: Faulty fuel hose...

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Very glad that we were helpful, let us know how the problem resolves, Robt.! 

 

I had a 1950 CJ-3A, purchased in 1969.  It was my first Jeep project, though at that time it was more service work than full restoration.  Learned a lot and enjoyed that Jeep, it ran with a metal half-cab and topless, an L134 and 12V electrics conversion, roll bar and otherwise stock.

 

Your Jeep sounds fun and functional...Share some photos at the forums Garage Photo Gallery, Robt., we'd all like to see it!

 

Moses 

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