cygnusx1 Posted March 27, 2009 Share Posted March 27, 2009 So is the Carter pump better at sucking fuel out of the tank and feeding it at low pressure to the Walbro? Just trying to understand. Link to comment Share on other sites More sharing options...
X64v Posted March 27, 2009 Author Share Posted March 27, 2009 Yeah, that seems to be the reason why this is working. The carter pump is of a different design (perhaps creates more suction head, perhaps is less prone to cavitation, or both), and in addition it doesn't have to put out much pressure on the other end. In this configuration, the Walbro is almost dead silent, far quieter than it ever ran. You can only hear it if you actually pop the hood, and even then it's faint. The Carter is audible for about the first 30 seconds or so, then fades away under the noise of the engine idling (even with the radio off). Link to comment Share on other sites More sharing options...
tory Posted April 22, 2009 Share Posted April 22, 2009 Sorry to dig up an older thread, but I was wondering if your new fuel set up seems to be working well still? I found this thread on google and have had the exact same problem, even after several reconfigurations of the fuel system (including replacing the Walbro with a Bosch 044, addition of a dedicated surge tank, etc...). I have an aircooled volkswagen instead of a Z, and most people can get away with gravity feeding the high-pressure pump because our front-mounted tanks are fairly high and have plenty of places to mount the pump underneath. So before I spend money on a new high-pressure pump, I thought I might be able to resurrect one of them with a feeder pump, and was just curious if your problems are cured. Thanks! Link to comment Share on other sites More sharing options...
X64v Posted April 22, 2009 Author Share Posted April 22, 2009 Yep, so far so good, I haven't had a single issue with this set-up. I'll be driving out to LA this weekend, when I get back I'll post to let everyone know if it worked for the 8 hour drive. Link to comment Share on other sites More sharing options...
DeleriousZ Posted April 22, 2009 Share Posted April 22, 2009 just curious, but did you ever clean/flowtest your injectors when you were having these issues? Link to comment Share on other sites More sharing options...
X64v Posted April 23, 2009 Author Share Posted April 23, 2009 just curious, but did you ever clean/flowtest your injectors when you were having these issues? No. I was losing pressure at the rail, something the injectors cannot effect unless they can outflow the pump (my 400cc injectors can't). Link to comment Share on other sites More sharing options...
X64v Posted April 28, 2009 Author Share Posted April 28, 2009 I'll be driving out to LA this weekend, when I get back I'll post to let everyone know if it worked for the 8 hour drive. No problems. The helper pump was the fix. Link to comment Share on other sites More sharing options...
tory Posted April 29, 2009 Share Posted April 29, 2009 Cool. Thanks a lot for posting your progress Sean. As far as the routing goes, did you hook up the Walbro directly to the Carter? I read that the Carter pump has a built in bypass valve that regulates the (low) pressure so you don't have to worry about straining the pump (the Carter flows more GPH lower pressure, the valve prevents strain). Just asking because people on the ACVW forums were telling me to run the surge tank in between the two, and connecting the return line to it to vent excess pressure buildup. But you sound like you've had good luck with a direct line. Link to comment Share on other sites More sharing options...
X64v Posted April 29, 2009 Author Share Posted April 29, 2009 One could run a surge tank, sure. My fuel tank is sump'd so I really didn't see a need for one, I have one directly plumbed into the other. The Walbro really seems to like getting 5psi of pressure to its feed fitting, and all the fuel is flowing fast enough that the Carter is happily flowing away even at max pressure. It's no where close to the same situation as deadheading the Carter with a carb setup (which one can do with a Carter). If I eventually get the car fast enough and cornering hard enough, I may run a surge tank to compliment the sump in combating fuel starvation, but for now it's a non issue. Link to comment Share on other sites More sharing options...
tory Posted April 29, 2009 Share Posted April 29, 2009 I figured the same thing with the direct feed. It's good to hear it works that way. I think I will hook it up the same way you have, when I get some more cash to spend. Now I have to go dig up that old Walbro and see how it works! If it's still crap I can still use the AN fittings with a new one. Thanks again Sean. -tory edit: BTW, awesome car. One of the guys at a dyno shop around here had a beautiful early Z with a built six from a later model, gnarly single turbo, massive front mount, and cheater slicks. I couldn't tell you all the specs, I'm not familiar with these cars. But they sure are sexy. Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted April 29, 2009 Administrators Share Posted April 29, 2009 Great info, now a stickie. Link to comment Share on other sites More sharing options...
ktm Posted April 30, 2009 Share Posted April 30, 2009 I would like to offer my own experience that is counter to Sean's. I have the same pump, but with a smaller run of hose from the pick-up to the pump inlet, feeding 72 lb/hr injectors. I do not have a single issue what so ever with the Walbro pump. The issue could be more about the sensitivity where a Walbro is located rather than implying that all Walbro's will have this issue. Link to comment Share on other sites More sharing options...
tory Posted April 30, 2009 Share Posted April 30, 2009 This is where mine was under the tank, and it started doing the screaming meemies after about 10 miles of test driving. So I think results can really be all over the place. Link to comment Share on other sites More sharing options...
ktm Posted April 30, 2009 Share Posted April 30, 2009 My pump was pushing against a base fuel pressure of 53 psi, up to 75 psi under full boost, with no problems when I was running 42 lb injectors. As you said, results are all over the place. One issue could be the quality of the "Walbro". Apparently there are quite a few Walbro knock-offs floating around. Link to comment Share on other sites More sharing options...
X64v Posted April 30, 2009 Author Share Posted April 30, 2009 I would like to offer my own experience that is counter to Sean's. I have the same pump, but with a smaller run of hose from the pick-up to the pump inlet, feeding 72 lb/hr injectors. I do not have a single issue what so ever with the Walbro pump. The issue could be more about the sensitivity where a Walbro is located rather than implying that all Walbro's will have this issue. Mine was located in the same place as yours with right about the same feed setup, and worked great for 14 months. It only started acting up after coming back from the body shop. To this day I don't know why. Link to comment Share on other sites More sharing options...
ktm Posted May 1, 2009 Share Posted May 1, 2009 Sean, you stated earlier that your feed line was ~4 ft long. I was using that statement to form the basis of my statement. My feed line is much shorter. It's hard to say what your true problem may have been. I am not saying you are wrong, I am just offering evidence that the problem may not truly be with the Walbro pump. You yourself said it worked fine for 14 months and 20k miles. Something changed. Link to comment Share on other sites More sharing options...
X64v Posted May 1, 2009 Author Share Posted May 1, 2009 Sean, you stated earlier that your feed line was ~4 ft long. I was using that statement to form the basis of my statement. My feed line is much shorter. It's hard to say what your true problem may have been. I am not saying you are wrong, I am just offering evidence that the problem may not truly be with the Walbro pump. You yourself said it worked fine for 14 months and 20k miles. Something changed. The feed line I'm currently using is ~4ft. The feed line I was using when it started acting up was about 1 foot, using the stock tank pick up. And yeah, I agree, the pump itself wasn't the problem. Otherwise the 280zx pump would have worked, or simply replacing the Walbro would have worked. But I don't have the slightest clue what did change when it started doing this. Link to comment Share on other sites More sharing options...
jgkurz Posted May 19, 2009 Share Posted May 19, 2009 Is the tank building pressure, or vacuum when driving? Try driving with the cap off.Just a thought. Mike Just this weekend I noticed that my Walbro pump was MUCH louder. I especially noticed the louder whine when I pulled in the garage and could hear the pump from outside the car. Coincidentally I was also hearing a strange squeal noise coming from the gas tank. I popped my gas cap and it about sucked my arm into the tank. Looks like my cap is not properly venting. I restarted the car with the cap off and the pump was back to it's usual quiet self. Link to comment Share on other sites More sharing options...
tory Posted May 20, 2009 Share Posted May 20, 2009 Yea, that's weird. Before I had routed my tank venting lines, I had the ports capped off... took it for a few test drives around the block and noticed the tank was swollen with air pressure, so I pulled off the cap too. Funny enough though, this was long before the pump started acting up and making noise. The only reason I noticed the tank being puffed up was because I was driving without a hood, and the fuel gauge sending unit on top of the tank was hissing. Hey Sean, you mentioned that you have 2 Walbro's that you tried. Which one is on the car now? I just got the Carter pump, and now I'm making all the fittings for it to work. I want to try out the old pump to see if the feeder solves the problem. If not, I can at least harvest the AN fittings from it and get a new one. Link to comment Share on other sites More sharing options...
X64v Posted May 24, 2009 Author Share Posted May 24, 2009 Hey Sean, you mentioned that you have 2 Walbro's that you tried. Which one is on the car now? I just got the Carter pump, and now I'm making all the fittings for it to work. I want to try out the old pump to see if the feeder solves the problem. If not, I can at least harvest the AN fittings from it and get a new one. The newer one is on the car now. I figured if they were both good, I might as well sell the older one and keep the newer one, since they were both technically used. The person to whom I sold the old one has not said anything so I'd assume it kept working fine. Link to comment Share on other sites More sharing options...
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