beaniam Posted April 14, 2014 Share Posted April 14, 2014 Finally got around to getting a gauge on my pallnet fuel rail. Currently there's a walbro 255 and the stock turbo FPR and stock fuel lines. Back when I first put the gauge on it was still pretty chilly out and at idle I had about 30psi and 35-37 with the vacuum line disconnected. Now today was about 77 degrees and I took it for a spin. After it heated up I started to get a lean surge and the wideband was actually leaning out to the point of not reading (16.xx+). So I took it easy and got it home. Checked the pressure now that everything had heated up and I'm down to 19-20psi at idle and about 23-25 with the vacuum disconnected. The pump seems to sound the same as the day I got it. The gauge holds pressure without dropping as long as I stood there watching it after shutting the car off. I have no cold or hot start issues. Time for a 1:1 adjustable pressure regulator? Aeromotive? Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 14, 2014 Share Posted April 14, 2014 The standard test is to pinch the return line. If pressure goes up, it's the FPR, no change it's the supply before the FPR. Pump, filter, fuel lines, strainer, suction side leaks allowing air in, dirty tank...all that. Quote Link to comment Share on other sites More sharing options...
beaniam Posted April 14, 2014 Author Share Posted April 14, 2014 I'll give that a try tomorrow. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted April 14, 2014 Share Posted April 14, 2014 I had problems with walbro pumps when I had my turbo z.They will not pull fuel upwards and need to be mounted lower than the tank .If you study the oem fuel system you will notice that the pump location is lower than the tank.I ended up running a Bosch 044 pump mounted in the stock position with a Earl's 80 micron filter before the pump.Then I changed the oem line to 3/8" with a gm fuel filter and Earl's fittings with pushloc hose.The walbro 255 pumps are adaptations from an intank application.They work well in a tank but they aerate the fuel when they get hot-not mounted in a tank to be cooled by fuel.I used to idle my car whille working with the efi software and the fuel + lines would get hot.When you get 10% ethanol your boiling point on your fuel drops.Nice thing about a 77 tank is that you can stuff 3/8" pushloc hose with a clamp on it. Quote Link to comment Share on other sites More sharing options...
beaniam Posted April 14, 2014 Author Share Posted April 14, 2014 Well what I've found is that when I start it up cold, it will hold 30/37 vac on/off. As soon as it warms up it drops to 20/30psi. If I shut the engine off hot but leave the fuel pump running (I have it on a switch) it will jump back up to 30/37. Start the engine and it goes back down to 20/30. The only difference between now and pre lean issue is I installed a pressure gauge. One of those liquid filled mashall gauges. My walbro is mounted just about flush with the bottom of the tank and I've got about 2/3 of a tank. With the engine warmed up after running a while the pump stays cool to the touch. Return line is only a little warm. I ordered an aeromotive universal 1:1 afpr. Should be here tomorrow. Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 14, 2014 Share Posted April 14, 2014 (edited) You might think twice about Aeromotive. They make cool race stuff, but their regulators all leak down as soon as the pump turns off. Makes for many extra turns of the engine waiting for the rail to re-pressurize. They're not really good for daily drivers. Edit - since I'm here, might as well say you should still pinch the return line, it could still be the pump. Unless you're really just itching to get a new regulator. And, by the way, the stock FPR's are 1:1. Not clear why that's spelled out. Anyway, good luck with it. Edited April 14, 2014 by NewZed Quote Link to comment Share on other sites More sharing options...
beaniam Posted April 14, 2014 Author Share Posted April 14, 2014 I forgot to mention I did pinch the return line. Pressure goes up quick and starts to rock the fuel rail away from the injectors. So I don't think I've got a starving issue. Leak down really isn't an issue as I typically have my fuel pump switched to come on as soon as you turn the key to on. This isn't a daily driver. I also removed the vacuum line and plugged the intake, holding at 31psi. I took it for a ride, still leans out but not quite as bad. Quote Link to comment Share on other sites More sharing options...
beaniam Posted April 26, 2014 Author Share Posted April 26, 2014 so does this look like a partial clog? http://youtu.be/ZMPwz6g3ZvM can't really find any videos of a walbro 255 flow rate but I'm guessing this isn't very good. It's weird pressure never drops when running, just starts leaning out. guess I'll drop the tank. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted April 26, 2014 Share Posted April 26, 2014 You might think twice about Aeromotive. They make cool race stuff, but their regulators all leak down as soon as the pump turns off. Makes for many extra turns of the engine waiting for the rail to re-pressurize. They're not really good for daily drivers. Edit - since I'm here, might as well say you should still pinch the return line, it could still be the pump. Unless you're really just itching to get a new regulator. And, by the way, the stock FPR's are 1:1. Not clear why that's spelled out. Anyway, good luck with it. I've used an Aeromotive FPR on my car for 5 years, I treat it as a daily driver in the summer, I have no issues with starting the car. It also takes many 10s of minutes for the fuel pressure to drop after the engine shuts off. I have several friends that also use Aeromotive FPRs on their cars without issue. Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 26, 2014 Share Posted April 26, 2014 (edited) Well, some do and some don't then. Just offering a consideration, for the OP's own due diligence. Search the web and you'll find many posts about Aeromotive regulators leaking down. Actually, many posts about most of the regulators that look like the Aeromotive style. Probably knockoffs. I think it's just a poor design. A cast aluminum housing, with lots of holes drilled in it for distortion causing fixtures, with a big steel ball in a diaphragm controlling flow. The seat area is left as-cast. Designed for high flow according to Aeromotive's descriptions. Maybe the higher end regulators get more finish work. Mine was the low end model, #13301. I actually sent an e-mail to Aeromotive back in 3/2011 and had an exchange that indicated they were going to address the leak-down in their instructions and in their FAQ section on the web page. It never happened. Copied below, with the name of the tech removed. He was a nice guy, and probably got over-ruled by marketing (I'm a cynic). Just one of those interesting things. Edit - Figured I might as well pile on with a few links. At the bottom. Q: “I recently installed an Aeromotive EFI regulator and when I turn the key to off, and my engine stops running, the fuel pressure immediately falls to zero. With the stock regulator this did not happen, is there something wrong with my new Aeromotive regulator?” A: The stock EFI regulator was engineered with a mandate to hold fuel pressure for 30-minutes after engine shut-down. This is an government regulation with which new car manufacturers must comply. Unfortunately, the mechanism used to hold fuel pressure when the engine is off, has a derogatory affect on a high-flow, adjustable regulator’s ability to create and control fuel pressure when the engine is on. Aeromotive places fuel system performance when the engine is running, particularly running under high load, at the top of the priority board. Anything, such as a checking mechanism in the regulator valve, which compromises fuel flow and pressure control under high-load engine operation, is therefore eliminated. We believe this no-compromise approach to fuel system performance is one of the reasons Aeromotive fuel pressure regulators are universally preferred by enthusiasts and racing professionals alike, around the world. And here is the proposed text for the installation instructions: Note: Aeromotive EFI regulators are fully optimized for ideal fuel flow and pressure control during actual engine operation. Do no be alarmed if your Aeromotive, high-flow, adjustable regulator does not hold fuel pressure when the fuel pump/engine are turned off. This is normal behavior and in fact permits the use of a proper regulator-valve design which delivers superior performance when the engine is running! Just a few.... http://www.dsmtuners.com/forums/bolt-tech/431671-opened-up-my-aeromotive-afpr-today.html http://www.rx7club.com/3rd-generation-specific-1993-2002-16/aeromotive-fuel-pressure-regulator-765888/ http://www.supramania.com/forums/showthread.php?175670-Aeromotive-FPR-dropping-pressure http://www.ca.dsm.org/forums/ubbthreads.php?ubb=showflat&Number=379543#Post379543 Edited April 26, 2014 by NewZed Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted April 26, 2014 Share Posted April 26, 2014 I'm using the 13109 on my Turbo L28, a friend of mine has been using a 13101 for over a year (maybe two now) on his daily beaten '71 Cutlass (with a custom EFI system), another friend just installed a 13101 on his Supra, and other people I know have used various (Aeromotive) regulators without any issue. :shrug:I really don't see the falling off of fuel pressure as an issue anyway. Typically in an EFI system the fuel system is primed as the key is turned on to supply fuel for start up, anyway. Even if the fall of pressure causes a few extra rotations at start, that's not such a bad thing, it can help with getting oil through the engine to the important parts before it lights off. Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 26, 2014 Share Posted April 26, 2014 An engine that starts at the touch of the key is just one of those simple pleasures. Quote Link to comment Share on other sites More sharing options...
beaniam Posted April 26, 2014 Author Share Posted April 26, 2014 (edited) Well I'm stumped. I've got the pump and fuel tank off the car and the pump directly powered by a jump box in a can of gas with a strong shooting stream of fuel shooting back out of the return line and a steady 35psi while running. It still leans out. I don't get it I haven't changed any computer settings, starts, runs then the afr climbs to 17, it lopes, drops back down to around 12 and repeats. Usually stalling. New aeromotive fpr, new bosch 440cc high impedance injectors. Any quick settings to give a look at that may point to this? Wideband sensor going bad? Driving me nuts. It went from leaning at wot and boost at the start of this thread to not even idling at an acceptable afr without loping with no computer settings changed. New injectors to replace the venoms and the new FPR. I've found the only way I can get it to idle decently is to raise the required fuel all the way up to 11ms Edited April 26, 2014 by beaniam Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted April 26, 2014 Share Posted April 26, 2014 Do you have a fuel injector that is failing to function when warm/hot? Quote Link to comment Share on other sites More sharing options...
beaniam Posted April 27, 2014 Author Share Posted April 27, 2014 They are new injectors. I don't know how or why but something was causing it in that fuel map. I loaded a backup from a couple months ago and it's running great. Albeit richer than I'd like. I'll have to mess with veal. Gotta start looking for a hx35 too. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted May 14, 2014 Share Posted May 14, 2014 I haven't driven my car enough in the past while to check, but I was running into this same issue. I eventually switched from my Walbro to a Bosch 044 pump. Even that would start to get loud, I then remade the bracket so the pump now sits lower than the fuel tank output barb. Also I made sure that it was mounted horizontally. One thing I noticed with all these aftermarket pumps is that the old factory relay and small gauge wire is not enough. Once the car and pump were warmed up I was losing as much as 1v between the relay and the pump, not to mention my relay was really hot. I found an older post from JeffP over on Z31Performance where he was talking about the same thing. The best solution is to run one of those large 70amp electric fan relays and then run 10 gauge wire directly to the pump. I also ran the pump's ground to the where the taillights ground in the back of the car so it would make for a shorter circuit. This made a big difference as far as running goes. I didn't seem to be encountering the issues anymore. I also agree with randy 77zt. I've just not had great experience with Walbro and in my searches to solve my fuel problems I found more than enough complaints about Walbros. I agree that they're really meant to be used with an in tank application, or to be an inline pump to increase an existing in tank pump. Quote Link to comment Share on other sites More sharing options...
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