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Post by matthugie on Jul 28, 2013 17:03:19 GMT -5
So, basically I have had some issues with fueling my car. The stock pump couldn't keep up with the new engine so I put in a Walbro 255, but I keep springing leaks. It seems that it's putting out more pressure than regular fuel line can put up with, especially the small in-tank line that connects the fuel pump to the hard line (see pic below). Does anyone have a suggestion of line I can use that will handle the abuse I'm throwing at it? Thanks. Edit: I thought I had this in the tech section, mods feel free to move it.  |
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Post by CoolGuy094 on Jul 28, 2013 18:49:22 GMT -5
Matt, does your car have a fuel pressure regulator? Isn't the fuel line that goes from the tank up to the FPR fairly low pressure, and the lines that go from the FPR to the fuel rail the only "high pressure" fuel lines? Pretty sure that's how my car is...?
Is that a braided hose that burst right there? I had the same Walbro in my setup before, just seems odd...
Maybe you can take this opportunity to upgrade to an Aeromotive 340 and get rid of the infamous "Walbro Whine". I swapped to the Aeromotive and it is muuuch quieter.
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Post by matthugie on Jul 28, 2013 19:06:25 GMT -5
I do have a FPR, but this little hose from the pump to hard line is the one that keeps crapping out. I've had some leaks before the FPR, but this is the only hose that has failed, and has done so twice.
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Post by CoolGuy094 on Jul 28, 2013 19:43:14 GMT -5
What PSI is the hose that keeps failing rated for? Only thing I can think is to go buy some higher rated hose. You aren't having fuel delivery problems otherwise are you? Maybe something is restricting flow from the pump to the regulator? Causing pressure to build up post-pump and blow that hose?
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Post by Steve Eckerich on Jul 28, 2013 19:49:05 GMT -5
Regular fuel line is only good for about 20 psi and less when submerged in fuel. Buy the high pressure line specifically for fuel injection and it should fix the problem.
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Post by matthugie on Jul 29, 2013 7:34:49 GMT -5
Thanks for the input. I'm pretty sure that this line was rated to about 4 bar, which is ~50psi. As far as I know local auto parts stores don't carry anything higher, but I'll see what I can find. Thanks.
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Post by illbebetter on Jul 29, 2013 8:03:04 GMT -5
You could try air hose. I had a TB coolant line fail and ACEe hardware was the only place in walking distance. They had several spools in different sizes. It should easily handle the pressure.
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Post by CoolGuy094 on Jul 29, 2013 9:30:23 GMT -5
Matt I've found 100 PSI fuel line in autozone before; not sure of what size it was though.
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Post by lancer360 on Jul 29, 2013 13:58:31 GMT -5
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Post by matthugie on Jul 29, 2013 15:54:13 GMT -5
Thanks Chris, I just ordered some of the Goodyear hose, and also have ordered a new sock for my fuel pump. My FPR is stock, which I believe is 3.5 bar. That is actually the only part of my fuel system that I haven't replaced yet, might that be causing some of my issues?
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Post by lancer360 on Jul 29, 2013 16:16:22 GMT -5
Hmmm, I wonder if the new high flow fuel pump is overwhelming the stock regulator. If the regulator can't relieve the excess flow back to the fuel tank fast enough the pressure will be higher than you want. This will cause excess stress on the fuel pump and could lead to it burning up. Is the regulator before or after the fuel rail?
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Post by CoolGuy094 on Jul 29, 2013 16:53:25 GMT -5
Regulator should be before fuel rail... On S2000's we run stock FPR with aftermarket fuel pumps all the time (even in dual pump setups). Not that it applies to your setup... just FYI.
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Post by matthugie on Jul 29, 2013 16:54:00 GMT -5
FPR is before the fuel rail.
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Post by lancer360 on Jul 30, 2013 9:09:30 GMT -5
Since the FPR is before the rail then that won't effect the pressure to the injectors. On our race car we run the FPR after the fuel rail. This way the injectors always have access to the full flow from the pump and the FPR just reliefs the excess flow as needed to hold the pressure. This is what Aeromotive recommended to us. With the FPR before the injectors then 100% of the flow for the injectors has to go through the FPR. Depending on how much you increased the horsepower the stock FPR might not be up to the task. If you suspect issues it might not be a bad idea to plumb a electronic fuel pressure gauge on the hose going to the rail and go out on to some quiet roads and to some runs at full throttle with a friend watching the fuel pressure to see if it drops. You don't want to have the engine go lean due to inadequate fuel flow.
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Post by matthugie on Jul 30, 2013 9:34:17 GMT -5
I've only increased the power of the engine by about 15%, so I would think the stock FPR can handle it without issue. I also haven't heard of anyone with a similar setup having FPR issues, though it's quite possible that mine is on its way out. It's at least 14 years old, and more likely closer 19. If what I have coming doesn't resolve my issues I'll throw a new one in, they aren't too expensive. Thanks.
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Post by CoolGuy094 on Jul 30, 2013 18:52:48 GMT -5
I feel like if your fpr was on its way out you would be having fuel delivery problems (lean/rich conditions, misfires, hesitations, etc). The only way I see and fpr leading to excessive pressures between the pump and fpr is if the fpr was failing closed, at which point you would see lean conditions and hesitation. When my old adjustable fpr failed, it was failing open causing rich conditions and misfire/bogging.
My car has nearly 200% the HP it had from the factory and the fpr of choice is still the OEM fpr. I think you just have a case of crap-tacular hose.
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Post by matthugie on Jul 30, 2013 21:40:32 GMT -5
I've been having lean conditions up top intermittently, but the question is whether it was just the hose leaking or if the FPR might have had its hand in it as well. The parts should be in tomorrow or Thursday, so we'll have a chance to test it out soon enough. Since I'm running with the PCA this weekend I decided to order a new FPR too, just in case. I'll test the car with just new hose and sock and see if that resolves it, and if not throw the FPR in. If that doesn't do it it'll be time to check the injectors, but I'll cross that bridge if (or when) I get there. Thanks guys.
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Post by Steve Eckerich on Jul 30, 2013 23:00:36 GMT -5
Going to ask a stupid question here, but do not know your system.
If the FPR is before the fuel rail on a system with no other regulator how does it hold pressure? It does limit the fuel into the rails to no more than the preset, but must have a return line. Is the return after the injectors? If so you are really not setting pressure at the injectors because as they work the pressure drops unless you are overloading the rails. You really are not controlling pressure in the entire system. Kind of like blowing up a balloon to 60 psi and opening the valve and saying you have 60 psi out. You do, only if the air around you is sealed.
FPR for carbs is in front. FPR for injection should be on return line after injectors to have consistent pressure. You will burn out pumps as the fuel pump is basically being made to bind up or blow the internal bypass to release extra pressure. With FPR after injectors they see constant pressure and the FPR just bleeds extra fuel back to tank. Now if the FPR is on a sealed rail system and the return is also at the FPR so it bypasses before the injectors it will work in stock form, but is known to drop pressure to the injectors at the end of the system.
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Post by matthugie on Aug 2, 2013 6:00:12 GMT -5
Steve, when I got in there I realized my FPR is after the rail. I thought the lines under the intake manifold were run differently.
However, I did find the source of my problems doing this, which is that my gas tank is horribly rusted. This had clogged my relatively new fuel filter as well as my fuel pump sock. New filter and sock and my pump is quiet and the car again has some power. I'll be ordering a new tank next week, which will be a blast to do I'm sure.
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Post by CoolGuy094 on Aug 2, 2013 7:38:16 GMT -5
Duuuuuuuude that sucks. Was the sock on the old filter clogged or rusty when you swapped the Walbro in? Wonder when moisture got in there to rust it up like that... Unless you made some enemies and they dumped some bleach in there. Tire class HAS been pretty competitive this year...
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Post by Steve Eckerich on Aug 2, 2013 8:10:40 GMT -5
Glad you found the problem. With all the ethenol in fuel today it seperates and attracts moisture. Pour some in a glass jar and wait a day. Over an inch will be watery.
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Post by matthugie on Aug 2, 2013 8:12:58 GMT -5
The sock from the stock pump was discolored, but I was told that pretty much all stock socks look like that just due to age. The sock that came with the walbro didn't fit my tank and the OEM sock seemed ok so I reused it.
As for the cause, it was definitely tire class sabotage. Someone was scared three years ago knowing I would start autocrossing, that tire class would be created, and I would almost finish higher than third once. Open and shut case.
I bought the car after it had been run out of gas and parked for about 3 years. I'm sure some moisture just got in there and started the process during that time. If I drove the car for more than 2-3k per year this probably would have surfaced earlier. Oh well, it's the price I pay for using a 25 year old car.
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