Jump to content
HybridZ

Fuel pump question


Recommended Posts

Where would i locate the fuel pump to try and start this thing. I checked my lines and I checked my wires, but the fuel pump doesn't seem to be turning on

 

 

the car turns over and everything, but i hear no audible hint of the pump turning on at all, and the fuel filter being dry tells me it's not. the start is turning the engine over fine.. which is ag ood sign, since my car hasn't started in 25 years.

 

i changed oil, filter, fuel, filter, and i got the wiring all done, so im wondering if someone can tell me where i can locate the fule pump wires and which ones i would have to connect to another battery to see whether she starts, before i pull this engine and sell it or clean it up.

 

its a 76 280z, FI, ecu is brand new. all guages light up and work, and wiring looks in excellent shape, but im not sure why the pump not turnin on =(

Link to comment
Share on other sites

so i checked the fuel pump. took it off the car, and drained the gas back into my canister so it wouldnt spew all over the place.

 

then it took the motor to a spare battery or two i had layin around, and applied straight voltage to see if it would start scrubbin, and it didn't do anything.

 

so i know that apply power when the motor is dry is a bad idea, but as soon as i hear that buzz, it's going back in.

 

but no buzz, no fuel =(

 

how much these tingz go fer?

Link to comment
Share on other sites

update.

 

took apart the pump, whilst stripping the head on the screws, so i hvae to get new ones. im sure a regular hardware store would have something suitable.

 

i polished the little sun gear keeper thing. and i polished the little dowels as well. i found that the two tear drop shaped o-rings that were in there don't want to go back in.

 

my theory is that over time, the rubber just crept out of that trench by itself, and decided to lodge itself into the rotation of the pump gear, so now i polished all the faces of everything, and im buying two new pump gears tomorrow after work =)

 

wish me luck. Im pumping life back into her tomorrow :ugg:

Link to comment
Share on other sites

The FI engine Zs had some really crazy stuff controlling power to the fuel pump. The idea is if the car gets in an accident and the engine stalls yet the ignition switch is left in the on position, we don't want the fuel lines (possibly damaged) being pressurized to 25 -35 psi. (major fire hazard) So... mine (a 77) has a switch built into the AFM which only feeds power to the pump (through a relay I believe) if the AFM is at least slightly open. If you remove the boot off the front of the AFM and turn the ignition on, then sticky ya finger in there and open the flap a little, you'll hear the pump run. (this test is performed with the engine NOT running by the way) I think later models might also have it run through a oil pressure switch. No oil pressure, no fuel pump a run. Anyhow, your best bet is to look at the factory service manual for your year and check the wiring diagram. If you haven't got one, it's available to download off the net for free. I'm to lazy to find the link for you, search this site. keyword = FSM+download

Link to comment
Share on other sites

The FI engine Zs had some really crazy stuff controlling power to the fuel pump. The idea is if the car gets in an accident and the engine stalls yet the ignition switch is left in the on position, we don't want the fuel lines (possibly damaged) being pressurized to 25 -35 psi. (major fire hazard) So... mine (a 77) has a switch built into the AFM which only feeds power to the pump (through a relay I believe) if the AFM is at least slightly open. If you remove the boot off the front of the AFM and turn the ignition on, then sticky ya finger in there and open the flap a little, you'll hear the pump run. (this test is performed with the engine NOT running by the way) I think later models might also have it run through a oil pressure switch. No oil pressure, no fuel pump a run. Anyhow, your best bet is to look at the factory service manual for your year and check the wiring diagram. If you haven't got one, it's available to download off the net for free. I'm to lazy to find the link for you, search this site. keyword = FSM+download

 

yah i know about that. it's discussed in the fuel pump guide i read. but i found out that the fuel pump wasnt turning at all, until i fixed it, so now i think it will be ok.

Link to comment
Share on other sites

all solved, ladies and gents.

 

i went to the local "parts source" store to register my business account as well as to buy some o-rings. it turns out that they had one that JUUUUUST stretched to fit, and that with the impeller mid plate on there with the gasket it, it was juuuuuuuuuuuust sitting slightly raised, meaning that there was some room for it to seal and compress, which it looks like it did.

 

I was about to put 300 or so down on a good fuel pump for the future RB project, but i did the 2 dollar way first, and found out that after 25 years of NOT STARTING, this engine is still amazing and runs perfect. no problem at all. a bit of a low idle, but i think it's the AFM that's sticking, and the hole right behind the AFM in the bending pipe. as well as the throttle linkage sticking a bit, or the pedal return spring being rusty.

 

but it runs nicely. video coming soon

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...