jhowell34 Posted April 15, 2012 Share Posted April 15, 2012 I have a l24 with rounded su carbs that wont start. the car is turning over, getting spark and is within time but no fuel...i replaced the pump carbs were rebuilt few years ago but wont start. there is fuel in the bowls but its not getting to the cylinders for some reason. car wont even start with eather? Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted April 15, 2012 Share Posted April 15, 2012 Is the air box on or off when your trying to start it? Try starting it with it off and if it does the carbs may need adjusting. Did you try using cold start spray? Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted April 15, 2012 Share Posted April 15, 2012 Is there oil in the su's? Quote Link to comment Share on other sites More sharing options...
jhowell34 Posted April 15, 2012 Author Share Posted April 15, 2012 Is there oil in the su's? box is off when i try to start it Quote Link to comment Share on other sites More sharing options...
jhowell34 Posted April 15, 2012 Author Share Posted April 15, 2012 box is off when i try to start it what if there is oil in the carbs Quote Link to comment Share on other sites More sharing options...
jhowell34 Posted April 15, 2012 Author Share Posted April 15, 2012 there was little oiled i cleaned out but for some reason the fuel pump gets the gas to the bowls but not fromt the su chambers to the intake i dk why...i wonder if i have enough fuel pressure maybe Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted April 15, 2012 Share Posted April 15, 2012 The su's are supposed to have some oil for the piston to move up and down in the carb. Maybe that's what's causing it? Is the float level correct? Check to make sure your floats also don't have fuel sitting in them. Is your spark strong, weak, look normal to you? Did you try the cold start spray yet to see if it starts and dies? If it does then you def have a fuel issue. Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted April 15, 2012 Share Posted April 15, 2012 The car should start and run even with the carbs not synced up. Wouldn't run that well though. Quote Link to comment Share on other sites More sharing options...
disepyon Posted April 16, 2012 Share Posted April 16, 2012 Maybe your fuel lines are not primed. I had a little fuel in my bowls, but the fuel lines didnt have any fuel in them, so i had to suck the fuel through the lines by mouth. Or your filter maybe clogged, i had that issue to, i just took it off and sprayed compress are through it. do you carb pistons move up and down smoothly when you compress them up by finger and let them drop down? Quote Link to comment Share on other sites More sharing options...
jhowell34 Posted April 16, 2012 Author Share Posted April 16, 2012 yea the carbs have oil and the pistons move up and down you know i bet i have to the fuel lines off and suck fuel through them haha its brand new fuel filter and pump though how can i prime the lines with a mechanical pump because there is fuel in the bowls but none of the fuel is getting to the fuel rail...and the spark is def strong Quote Link to comment Share on other sites More sharing options...
disepyon Posted April 16, 2012 Share Posted April 16, 2012 (edited) yea the carbs have oil and the pistons move up and down you know i bet i have to the fuel lines off and suck fuel through them haha its brand new fuel filter and pump though how can i prime the lines with a mechanical pump because there is fuel in the bowls but none of the fuel is getting to the fuel rail...and the spark is def strong Do not take this personally, but i am having a hard time understanding you. try to type with better grammar. So you have a new fuel filter and pump? You do or you do not have fuel in your lines? and you want to know how to prime the fuel lines? To prime, just kink one of the rubber hoses going to one of the carbs and then suck the other rubber hose until you suck fuel (do not swallow it of course). Once that hose is filled with fuel, do the same to the other fuel line. It wont fill up completely with fuel, but you should see your filter fill up with fuel slowly. It takes a while to suck the fuel. When the filter is filled up, keep priming it for a little while so the fuel can get into the pump. Then reconnect everything and crank the engine over a little bit so the lines can completely fill up and the bowls as well. If this doesnt work then your problem might be somewhere in the hard lines. Maybe they might be clogged up. Edited April 16, 2012 by disepyon Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted April 17, 2012 Share Posted April 17, 2012 Would you still have to prime the fuel lines if there's a fuel sending unit and a mechanicle fuel pump? I know i switched out my fuel filter and never ha that issue. Pump was never switched when I had the car up and running before the strip down. Quote Link to comment Share on other sites More sharing options...
jhowell34 Posted April 17, 2012 Author Share Posted April 17, 2012 hmmm.... Quote Link to comment Share on other sites More sharing options...
disepyon Posted April 17, 2012 Share Posted April 17, 2012 Would you still have to prime the fuel lines if there's a fuel sending unit and a mechanicle fuel pump? I know i switched out my fuel filter and never ha that issue. Pump was never switched when I had the car up and running before the strip down. Honestly im not sure about that. I would assume you would not need to prime the lines the way i said too (not even sure the way i said is correct, but a method of doing it that works). The electrical pump should prime the lines for you like a modern car. Just turn the key in the on position or until you hear the electrical fuel pump turn on and wait 30 seconds or so to allow it to prime the lines, then start the car. It may take a bit to start the engine since the electrical fuel pump may not completely prime the mechanical pump and the fuel rail lines too (but im not sure on that, ive never had both, is your datsun the 260z that came with both?)A good and quick way to test it is to hook it up to a battery, or some source of power and listen (that is if its off the car, if its already on the car just listen to it underneath the car). If you can hear the electrical fuel pump making a winding noise, chances are that it may be ok. if you really want to know it works, take it off the car and hook it up to a bucket of gasoline and power it up to see if it pumps any fuel out the other way. Or take a voltage reading using a voltmeter (this is actually the best way to test any electrical part). Also depends how long your car has been down for and if you did not drain the gas tank or lines. The gas in both pumps (mechanical for sure) i would assume to eat away at the seals over a long period of time, but that depends on how long you left your car undriven for. 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.