Metro Posted August 6, 2005 Share Posted August 6, 2005 Before you ask, yes I searched and I read the post a little ways down the page. This is driving me insane, I've tried everything I can think of. My pump sounds like someone is slowly letting the air out of a balloon. A real high pitch shreak but only after I've been driving it for a few minutes or if I rev parked for a while. It's very loud annoying sound, like you can hear it 20 feet away when my car is running and I have an open exhaust at the moment. From the sound I would guess would that mean there's an air leak and it's sucking air somewhere? I can't really understand how it can be doing that and not leaking any fuel, but then I'm a novice. I've also replaced and put teflon tape on all the fittings several times. Of course everything has clamped and is tight. Stock L28et in a 1976 280z Fuel stuff: JSK fuel rail and aeromotive RFPFR (not really needed right now since I'm bone stock) and -6AN flare fittings connecting it. I doubt any of that is affecting it, but there it is. What worked: The original pump is an aftermarket replacement pump made by Airtex and sold by Autostar. It has 5/16th and 1/2" in fittings. I also have a 1/2" inline universal filter between the tank and the fuel pump (my tank is full of crap). With this setup, I don't have any problems. I also have seen this pump listed as a replacement pump for the l28et cars, but not sure how much I trust that. What I have now Walbro GL392 5/16th and a bell to 1/4" NPT so I can run larged than 5/16th on the inlet. I run the same PSI as with the old pump, about 34psi at idle. The pump is bolted to the bottom side of the old fuel pump bracket which places it about 1" below the outlet line of the tank. To stop it from kinking, I used about 12" of line to reach the fuel pump. Originally I used a 3/8 line going to the filter and it ran ok, didnt' stumble and the gauge read 30-32psi at idle - even with it shrieking. I changed the inlet fitting to 1/2" and used half inch fuel line. Much worse now, almost died driving back home after a test run. At idle the FP was jumping between 5-17psi. As for filters, I've tried 3 different ones, so unless they all can't flow very much volume, it's something else. I haven't tried running it straight from the tank to the pump, because the crap in the tank might hurt the fuel pump, but damn, I might do it anyway to see. I've tried blowing air into the tank to see if there was anything stuck in the outlet too. At this point, I'm ready to say **** it and put the old pump back in. Anyone have any ideas or other things to check? Quote Link to comment Share on other sites More sharing options...
jkube Posted August 11, 2005 Share Posted August 11, 2005 I have the same pump on my 240z ( N/A with megasquirt). My pump did the same thing and I discovered that I had the aftermarket FPR hooked up wrong. I had placed it on the fuel line feeding the injectors, and the proper placement is on the return line. The FPR was squeezing down the main fuel line as I drove the car, but then would release when I shut the car off and restarted. The car would always run fine at idle and the pump wouldnt scream. It seems these pumps will scream like that when the main line is pinched or squeezed down. It will also do that when it cant pick up fuel from the tank. So if you have a stock tank, and the fuel is low, you can get the same result because the fuel is sloshing in the tank and the pump cant pick it up. Quote Link to comment Share on other sites More sharing options...
Metro Posted August 12, 2005 Author Share Posted August 12, 2005 Yeah the FRP is hooked up correctly, I made sure it was put in the correct place. Well, since I've posted this I've put the old one back in and not had a single problem. It's mounted in the same place with the same lines, so either there's something wrong with the walbro or it moves a lot more volume than the other pump. Quote Link to comment Share on other sites More sharing options...
akeizm Posted August 23, 2005 Share Posted August 23, 2005 How is it mounted? Mine used to sound like a really loud fan belt squeaking. And it was louder than my 3" exhaust. What I found was that you need to mount it horizontally (inlet and outlets facing the left and right sides of the car, or the front and back of the car). If its vertical (inlet and outlet facing the ground and the sky) it will not produce as much pressure and will scream its head off (think its trying to push air). In the installation guide for the pump it says to mount it in the same position as the old pump, well my old one was vertical. Quote Link to comment Share on other sites More sharing options...
Metro Posted August 23, 2005 Author Share Posted August 23, 2005 It's mounted horizontally, stock was horizontal too, but higher up. Quote Link to comment Share on other sites More sharing options...
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