New owner of '77 280z from Upstate SC

[Patcon]

11 minutes ago, Driver_X said:

Forgive me if you've already done this, but have cheked & cleaned the injector connections?   Mine were in such bad shape I just replaced them. 

Do you get much salt air, where you're at? That looks like what happens to cars that are around the beach. The aluminum normally gets tortured too.

[bartsscooterservice]

props to you injection goeroes...  

[EuroDat]

I changed my connectors on all the injectors, CSV etc with new quick release connectors. The previous owner did a rough job soldering the connectors he used. They were giving me interminttent missfiring on a couple of cylinders.

If you are testing the fuel pressure on your own, you can use a longer section of hose and mount the gauge were you see it. I did that to check the pressure while I was driving it. Simply taped it to the wiper arm and test drove with the bonnet adjusted so it wouldn't pinch the hose.

I made an instruction for testing the pump last year when I was playing with my spare pumps. I was almost done, but never got round to finishing it, so it will have some misstakes. See pdf. It might be some help.

 

 

Instruction - Fuel Pressure Test 280Z RevA.pdf

[siteunseen]

If you decide to straight wire the pump for a pressure reading (I would) speaker wire and alligator clips make it easy.  You may not have the OE Bosch pump?  And there is a positive and a negative post on them.  Here's some up close pictures thanks to Blue. 

http://atlanticz.ca/zclub/techtips/fuelpump/index.html  This shows the inlet filter that could be clogged.  Those things are very fragile and you'll need tweezers to pull it out for inspection.

 

[the_tool_man]

Describing what's going on, while limited to a keyboard, has its limitations!  Part of the problem is that I leave out details that seem minor.  Let me elaborate on my description:

The engine starts easily.  If I allow it to idle, it stumbles while idling, and dies after 10 seconds or so.  The AFM vane moves off its stop while idling.  If I rev it to 2000rpm or higher, it will continue to run.  While running, it continues to stumble (misfire, skip, whatever).  While it's running, the fuel pressure drops to "near zero" on the gauge I'm using.  That gauge has a pretty big range (0-160psi).  And "zero" looks to be more like 5psi.  So I can't really say it goes to zero.  I assumed, but didn't specifically communicate, that it was getting enough fuel to run even though the measurable pressure at the gauge is quite low.

I really appreciate all the suggestions.  They're pulling me in different directions!  But I'm going to concentrate on the fuel supply first:

• When I'm home next week (traveling in the UK at the moment), I'll test the fuel pump for pressure and flow, and investigate possible flow issues with the tank and lines.
• I've ordered a replacement FPR, since the one on the engine may well be original, and is suspect.  Hopefully, it will arrive early next week.  I realize the one I have may be working fine.  And I know how to test it.  But it's an easy job to replace it.  And I want to be able to take the car on long trips.  So for peace of mind, I'm going to just replace it.  Zed's theory about it leaking fuel into the intake sounds intriguing, as it explains the low pressure and rich mixture (if that's truly what's happening).  So again, one more reason to just replace the thing.

On my longer term list:

• I noticed my fuel gauge reads half-full.  I know the tank was full when I brought the car home (I filled it up).  So while not necessarily urgent, I need to sort it out pretty soon.  I may end up pulling the sender anyway during the course of the fuel supply investigation.  But if not, it won't hurt to pull it to inspect the inside of the tank for rust and debris.  If I had to drop the tank to do this, I'd probably put it off for as long as possible.  But between the tank drain and the inspection panel in the trunk, it looks like an easy job.
• I plan to replace all of the EFI connectors with new ones.  Firstly, the AFM connector on my car was missing the wire retainer, and is currently held on with wire ties wrapped around the AFM.  Secondly, while the contacts aren't green, they are somewhat corroded on many of the connectors.  I've inquired about replacement connectors from a guy (Kurk MacKay of MacKay Power Products) recommended to me on Hybridz.  He's been slow to communicate.  But he offers a kit that has everything I should need.  I've already ordered the pin removal tools and a new crimper to facilitate this.
• I still haven't completed all of the electrical tests as outlined in the EFI book.  I'll do these as time permits, just to eliminate other potential issues.
• I need to go through the ignition system, if for no other reason that to make sure everything is in good shape.

I have to repeat that amount of help here is overwhelming.  I'm not used to this.  Thanks!

Edited February 22, 2016 by the_tool_man

[Driver_X]

I would not hesitate to contact Mike at Bonzai motorwerks. He's got all the parts you need, but more importantly can point you in the right direction for getting your car running properly. Whatever you think your are "overpaying" for parts, he more than makes up for with his experience & expertise. He saved me HOURS of diagnosis time, and he got my Z as close to OEM (read reliable) possible. 

[siteunseen]

I replaced my fuel sender with a new one from Nissan.  After reading on here about the process I realized the arm had to be bent a little.  I think the new ones are straighter so they'll fit into the box.  Maybe your's needs to bent some?  If it's the original one, it may just need a good cleaning where the contact arm sweeps over the wiring.  Carburetor cleaner works good.  I was able to clean the one on my 280, the 240 had to be replaced, it was frozen from sitting in a cruddy tank full of 10 year old gas.

[Mark Maras]

 Before you give up on any (frozen, rusty, crusty) fuel sender, soak it in 100% CLR for 24-36 hours. I've done two. One frozen, one just plain ugly. Both look good and are usable now.

[wheee!]

I agree with Mark... I soaked min in CLR overnight, metered it out and is good to go!

 

[gwri8]

What they said, save it if you can.  You can find one for a 77' but it will cost you dearly!

http://www.zcarsource.com/gas-tank-sending-unit-280z-77-78-rebuilt-de_8_55266_52788.html

Edited February 22, 2016 by gwri8

[siteunseen]

I bought one from my Nissan dealership, $50 if I remember right. I've got the invoice with the part number and price if you need it. That CLR soaking looks pretty damn good though and much cheaper.

[wheee!]

It's worth a shot.