Posted November 25, 200717 yr comment_229699 ive pulled the fuel tank and flushed it out. ive blown through all the fuel lines. ive also pulled the pump which runs just fine. but when i put it back together i pulled the oil pressure sensor to bring the fuel pump on and seperated the fuel line below the filter and i am getting nothing. ive heard it can be difficult to prime the pump but i have at least 7 to 10 gallons of gas. what gives? Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/ Share on other sites More sharing options...
November 25, 200717 yr comment_229700 What year car for starters? Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229700 Share on other sites More sharing options...
November 25, 200717 yr Author comment_229701 its a 78 280z bosch fuel injection Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229701 Share on other sites More sharing options...
November 25, 200717 yr comment_229702 Have you checked that all of your relays are connected and active? Do you hear any sounds when you turn the key to the on position?When I replaced my pump, it took about 10 attempts to get the fuel flowing. Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229702 Share on other sites More sharing options...
November 25, 200717 yr Author comment_229705 when i disconnect the cutoff it comes right on. shouldnt it be pushing fuel out of the line i disconnected anyway? Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229705 Share on other sites More sharing options...
November 25, 200717 yr Author comment_229706 is the pump supposed to come on and stay on when the ignition is in the on position. and as well when its in the on position and i manually open the air flow meter gate? if its not, which relay is failing? Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229706 Share on other sites More sharing options...
November 25, 200717 yr Author comment_229710 and how come i cant find the fuel injection relay above the ecu and drivers side kick panel? Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229710 Share on other sites More sharing options...
November 25, 200717 yr comment_229711 I ran a jumper wire to the pump to prime it . After that it ran fine on it's own. Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229711 Share on other sites More sharing options...
November 25, 200717 yr Author comment_229714 isnt that the same as disconnecting the cut off? it doesnt give me any fuel from the line disconnected at the filter even then. Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229714 Share on other sites More sharing options...
November 26, 200717 yr comment_229757 "ive pulled the fuel tank and flushed it out" Ok, how long has the car sat and how old was the fuel you took out? The bosch L Jetronic uses a Roller vane pump. The roller cell is driven by an electric motor at over 3,500 RPM. This pump is capable of pressure in excess of 100 PSI which is far higher than any engine or F.I. system require. This is why this type of pump is located very close to or even inside the fuel tank because it does such an excellent job at pushing the fuel. My guess is A) it's just tired out internally or is junked up from the old rusty fuel, or C) both. I don't know how far you have gone looking at the fuel pump, but Just a thought. Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229757 Share on other sites More sharing options...
November 26, 200717 yr Author comment_229765 it sat maybe 6 months. no gas cap. but i did flush the tank very well and blew the pump and fuel line out as well. seemed in order. is it typical for the internal parts of the pump to wear out before the motor on the pump? Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229765 Share on other sites More sharing options...
November 27, 200717 yr comment_229875 Normally a bad pump will bypass a driveability problem and will just simply stop operating so typical? no, but it has and can happen and considering your Z sat for months without a gas gap and had some nasty crap ran through it, we are not talking about normal wear and tear here so I wouldn't rule out the possibility. Link to comment https://www.classiczcars.com/forums/topic/26343-why-no-pressure/#findComment-229875 Share on other sites More sharing options...
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