Dunlop Posted March 24, 2011 Share Posted March 24, 2011 I finally got the engine started the other day, but for some reason the fuel seems to leave the lines. It seems that the fuel flows back into the tank threw out a good portion of the line. Fuel pump is in stock location, can hear it even push air when it first engauges. This then stops after the engine starts and starts really sucking. However it just seems to take a wile for the pump to even get fuel and its just right there. I dont know whats wrong. Thanks Quote Link to comment Share on other sites More sharing options...
MONGO510 Posted March 24, 2011 Share Posted March 24, 2011 So, is this a Borgward or a DKW? Mongo Quote Link to comment Share on other sites More sharing options...
Dunlop Posted March 24, 2011 Author Share Posted March 24, 2011 So, is this a Borgward or a DKW? Mongo What? Quote Link to comment Share on other sites More sharing options...
jt1 Posted March 24, 2011 Share Posted March 24, 2011 Is the fuel tank vent functioning properly? Sounds like the pump may be pulling a vacuum on the tank. jt Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted March 24, 2011 Share Posted March 24, 2011 Yeah, you'll want to make sure the tank is venting appropriately. If you try to take the cap off and hear a woosh then that may be your problem. I vented my tank to the filler neck and my gas cap doesn't seal well enough to allow much vacuum to be formed. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted March 24, 2011 Administrators Share Posted March 24, 2011 Maybe I'm getting too old for this. I had to read it several times, and I *think* I know what he's saying, but I can't be certain. Dunlop, could you clarify a few things.... What year of Z? What fuel pump and where is it located? (saying "stock" doesn't mean anything) Carb'd or injected? Quote Link to comment Share on other sites More sharing options...
Dunlop Posted March 24, 2011 Author Share Posted March 24, 2011 Maybe I'm getting too old for this. I had to read it several times, and I *think* I know what he's saying, but I can't be certain. Dunlop, could you clarify a few things.... What year of Z? What fuel pump and where is it located? (saying "stock" doesn't mean anything) Carb'd or injected? 78 280z fuel pump is in stock location on the braket.... passenger side. 4 barrel DeMon carb I have had the Gas cap off and didnt notice anything. Even does it with the stupid cap off. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted March 24, 2011 Administrators Share Posted March 24, 2011 What are you using for a pressure regulator? Does it have return line back to the tank? Are you making use of the charcoal canister? Quote Link to comment Share on other sites More sharing options...
Dunlop Posted March 24, 2011 Author Share Posted March 24, 2011 What are you using for a pressure regulator? Does it have return line back to the tank? Are you making use of the charcoal canister? Two port holly type. It reads 5.5 once the fuel gets to it. No return line. No charcoal Canister. Also if anyone knows what hose to use for the slave on for a t56 let me know. I am confused on that also. Thanks again guys. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted March 24, 2011 Administrators Share Posted March 24, 2011 No return line. That pump is not designed to dead head like that. Must fix No charcoal Canister. I don't know how you're venting the tank, but you will need something. The canister is one of the 'nicer' ways to do it. Quote Link to comment Share on other sites More sharing options...
Dunlop Posted March 25, 2011 Author Share Posted March 25, 2011 That pump is not designed to dead head like that. Must fix I don't know how you're venting the tank, but you will need something. The canister is one of the 'nicer' ways to do it. I have a vent filter off the lower hose. What type of pump should i get then. The fuel pump i have must be the problem then. Anyone know about the t56 hose i need as well... The one i orderd does hook onto my wilwoods 7/8's master but the connection going to the slave is a quick connect. I hate making new posts just over single questions. Thanks again Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted March 25, 2011 Administrators Share Posted March 25, 2011 The fuel pump i have must be the problem then. I suppose that depends on how you look at it. I like the stock EFI pump. It's mostly quiet, reliable, and when run at low pressure will provide a LOT of fuel. It would serve you well with the proper regulator. If you'd rather keep your current regulator, then you need a different type of pump. There are plenty of electric pumps available for your application. Try jegs.com and summitracing.com. That'll get you started. Anyone know about the t56 hose i need as well... The one i orderd does hook onto my wilwoods 7/8's master but the connection going to the slave is a quick connect. I hate making new posts just over single questions. I believe that topic has been discussed a few times here. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted March 25, 2011 Share Posted March 25, 2011 You have a few options. I think you'd be better off buying a bypass fuel regulator and running a return line. Aeromotive universal diaphragm bypass regulator ($125), Barry grant diaphragm fuel bypass from jeggs(65is), and holly diaphragm bypass style(60). I went with the holley. I received the same advice RTZ gave you to run the same fuel pump with a return line. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted March 25, 2011 Share Posted March 25, 2011 Anyone know about the t56 hose i need as well... The one i orderd does hook onto my wilwoods 7/8's master but the connection going to the slave is a quick connect. I hate making new posts just over single questions. Thanks again The easiest way is to use a -3 hose and a roll pin adaptor for the slave side: http://www.jegs.com/i/Russell/799/640281/10002/-1 Quote Link to comment Share on other sites More sharing options...
Pyro Posted March 25, 2011 Share Posted March 25, 2011 use a return style regulator with the stock pump and stock return lines. aeromotive makes a nice one for $125 that can go down to carb pressure (5 to 7 psi). Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted March 25, 2011 Share Posted March 25, 2011 Pyro, that's the one I initially was going to buy but Jeggs had the barry grant and holley return style carbureted bypass diaphragm regulator for half the price. I guess I'll have to post a review after I run it. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 14, 2011 Share Posted April 14, 2011 So I was just reminded about this thread, but I hooked up my holley 12-803bp Which is their carbureted bypass style regulator. Ran the fuel pump and it seemed like an aweful lot of fuel was coming through. Way too much for 5.5 psi. I disconnected the return line and it wasn't bypassing. I called holley and they told me that the max inlet pressure is only rated at 20psi and they did not recommend usage for this scenario. I'm going to play with it a little more this weekend but this may not be a good option. (By the way, I can't manage to find max inlet pressures listed anywhere for any regulators) Quote Link to comment Share on other sites More sharing options...
letitsnow Posted April 14, 2011 Share Posted April 14, 2011 The easiest way is to use a -3 hose and a roll pin adaptor for the slave side: http://www.jegs.com/i/Russell/799/640281/10002/-1 I got mine(for my rx7) from speedwaymotors.com, it uses the factory quick disconnect on 1 end and a -3 AN on the other. Quote Link to comment Share on other sites More sharing options...
Pyro Posted April 14, 2011 Share Posted April 14, 2011 max inlet let is almost 0 psi with a stock efi pump and a return line. get a tee and a pressure gage. loop the gas back to the tank with the return line and measure the pressure at the tee. It will be near 0, maybe 1/2 psi. If your regulator isn't "bypassing" then it is not working or it is not connected correctly. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 14, 2011 Share Posted April 14, 2011 Haven't had much time but I did want to check the bypassing issue again. Double checked my connections so that wasn't the issue, but was concerned that the regulator may have been faulty. Will get back with you on that this weekend. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.