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My orange 260z was delivered just before Christmas.  It's an early model 74 (pre August).  It has an L28/N24/N24 head.  Round top carbs.  Early magnetic pickup distributor.  Factory AC with the old compressor.  5spd swap (I think lol).  I need to take the shifter cover off to make sure I actually feel 5 forward gears, and it's not just sloppy linkage lol.

 

Luckily the only rust I'm seeing is the drivers door.  But it has a dent in the rear quarter, drivers side, around the taillight area.  

 

The car was sold as running, but I wouldn't say that is entirely true lol.  There is a fuel delivery issue that I'm trying to track down.  It will run if I manually fill the bowls, but that's it.  Once the holiday season slows down, I'll throw an electric pump at it and see what that does.

 

There are all kinds of vacuum lines broken, plugged, and dangling everywhere.  So I'll need to track those down and may need some help identifying what goes where.  There are also a few sensors that have broken wires coming out of them, but if the engine fires up without them, I'm assuming they aren't critical.

 

The interior is pretty crusty.  Dashboard has more cracks than Keith Richards.  Wires hanging everywhere.  But hey, the seats are in decent shape, except they are in permanent Tupac-mode and recline as soon as you sit in them.  

 

It has brand new rubber lines to all 4 brakes and the clutch.  New master cylinder for brakes and clutch, and new slave for the clutch as well.  

 

My plans are to get this thing running and driving safely.  Brakes, lights, fuel delivery issue first.

Then it's gonna be tackling the interior, POR15 all over the place, etc...

 

Because this isn't a numbers matching car, it opens a lot of options for a powerplant in the future.  I'll take the L28 as far as I can, but if I get bored, I won't feel as bad throwing an LS in here.

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Edited by juggernautjoee
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Pretty sure the whole issue was lack of fuel lol.

 

I pulled the tank plug and maybe a cup or two of gas came out.  No chunks luckily.  Just dark, varnished gas.

 

I went ahead and dropped the tank after seeing how brittle some of these lines were.  The rubber was hard and I could easily break it in half with one hand.  I also bent one of the contacts for the fuel sending unit, so I might have to get another one of those.

 

The tank cleaned up pretty well with some purple power, brillo pad and a hose.  

 

I've got another electric fuel pump coming.  Not the same unit as the stock one, but I think I can get it to work in that stock location with the stock wiring.

 

I also blew the lines out with compressed air.  Nothing significant came out.  Just old dirty gas.  My garage is going to smell like gas for a few days I'm sure.

 

I'm thinking of at least painting the outside of the tank and the straps.  But what is everyones' opinions on either sending the tank off to be sealed, or doing it yourself with a POR15 kit?

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Edited by juggernautjoee
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One of the keys to getting a good result on sealing a tank is prep work and letting the coating cure completely.  If you're of a patient fastidious nature you'll probably get good results, if you're impatient and tend to cut corners, probably not.  There are threads around the internet about sealing tanks and how to get good results and which brands work best.  They're all the same, don't have to be Z tanks.

 

On the other hand, if there are no leaks and no large flakes of rust from the tank, just a good cleaning might be good enough.  Good luck.

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Honestly not sure yet.  I'm going to be pretty flexible on what my plans are.

 

If I find a good deal on parts to slap on the L28 (p90 head, headers, megasquirt and triple webers) for cheap, I'll go that route.

 

If I find a good deal on an LS near me, and the L28 is boring me, I'll do that.  

 

Most likely I'll just keep the L28 until I've at least got the interior in good shape, then I'll start looking for parts or an LS.

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Tank was flushed with acetone.  New sending unit installed.  

 

New battery cables and spark plug wires.

 

I threw some rust reformer on the tank and straps and then hit the tank with some gloss black.  I threw in some new rubber lines back there.

 

Then came the electric pump install.  I'm not getting 12v when on or cranking.  New pump works fine when tested.  Even the old pump worked (but sounded terrible).  I did some research and it looks like the 260z electric pump wiring goes through some relay and it either uses the oil pressure switch as a cutoff, or something else.  I'm getting mixed answers on that.  I'll try to figure it out later.  Or maybe just give up and run some new wiring for it.

 

I tried to run it just on the mechanical pump, but it doesn't seem to want to run for long.  I don't want to go chasing that squirrel until I know I've got good fuel coming from a new electric pump.

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8 hours ago, walkerbk said:

It doesn't make sense for the old pump to get 12v and the new pump to not  get 12v. Sounds more like its a ground problem. 

 

Use your multi meter to check voltage between the ground and source when on.

 

I guess my wording wasn't good.  Both pumps test fine when hooked directly to the battery.  I'm not getting 12v with a volt meter from the hot wire when cranking or running (I can get it running by filling the bowls manually for ~40 seconds).  So something in the wiring/relays is bad.

 

Thanks NewZed for that manual.  That'll help me track it down.  

 

Looks like the 260 should be using the alternator RPM as the kill-switch.  I wonder if my alt is bad, this would cause this issue.  

Edited by juggernautjoee
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The 260z fuel pump and interlock systems are a fun time for sure, been there done that with mine. There are two fuel cutoffs - one is the alternator as you say, and the other is (for some reason I have yet to figure out) a starter cutout. They're in-line, so if one triggers for some reason no voltage gets to the fuel pump. The 2nd cutoff relay kills the pump while the starter is cranking and a lot of people bypass it (was done on my car long before I got it, jump GW to BW on the relay plug and bob's your uncle).

 

Assuming the starter cut relay isn't acting up it's either going to be the alternator safety cut or a wiring issue most likely.

 

I did some tracing of the harness when I was troubleshooting some fuel pump and interlock stuff (interlock being related to cranking not fuel but was working on both at once); if you follow the neon blue wire (multiple colours in the real harness, just did that in the drawing for continuity) back it should give you some spots to check for voltage at plugs etc. you may need to right click>view in new tab to see the full size

 

VG5PbZu.jpg

 

You can also disconnect the pump entirely and splice in some hose to just go tank>lines>mechanical pump>carbs for testing purposes, they added the electric pump to try to stop vapor lock IIRC; the car will run fine on the mechanical pump only.

Edit: oh, and in case it helps, here's how I mounted my aftermarket electric pump. Basic square bracket that bolted to where the stock one went, rubber isolators, and a U bend from some nicopp hardline. Probably 1/4 the weight and size of the stock massive bracket.

 

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Edited by Noll
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Wow, thanks a lot Noll.  That diagram helps a ton.

 

I'm going to eventually replace the external regulating alt for an internal one, so I might as well run a new harness/relay for the fuel pump. Once I remove that voltage regulator, I'll trace the wires back and remove the relays and such to clean things up.

 

I'm going to loosely follow this - 

http://jarvas240z.blogspot.com/2013/01/electric-fuel-pump-installation.html

 

I've done the same thing when I had to switch from a manual to electric fuel pump in my 83 S10 when I did a 2.8L -> 3.4L swap.  It's a very similar process.  

 

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On 1/2/2022 at 11:01 AM, juggernautjoee said:

Wow, thanks a lot Noll.  That diagram helps a ton.

 

I'm going to eventually replace the external regulating alt for an internal one, so I might as well run a new harness/relay for the fuel pump. Once I remove that voltage regulator, I'll trace the wires back and remove the relays and such to clean things up.

 

I'm going to loosely follow this - 

http://jarvas240z.blogspot.com/2013/01/electric-fuel-pump-installation.html

 

I've done the same thing when I had to switch from a manual to electric fuel pump in my 83 S10 when I did a 2.8L -> 3.4L swap.  It's a very similar process.  

 

 

No problem at all! Yeah, that would be a solid way to go for sure; I'll probably end up doing the same at some point for the same reason (and I also plan to go EFI at some point probably with a surge tank, so double the reason)

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Posted (edited)

Did a few things today before the weather turns.

 

Changed the oil.  I went with some 15w-40 rotella heavy duty diesel oil.  I couldn't find any good high-zinc in a 10w.  I know this oil has a good amount of zinc and other dinosaurs/vitamins that these flat tappet motors want.  It might be a little thick, but it's not going to hurt anything right now. The old oil didn't smell like gas, so hopefully that's a good sign.

 

Rebuilt the carbs.  The carb closest to the firewall was very gummed up.  The jet was completed clogged.  After cleaning them both up, spraying out everything, the front carbs' piston drops a lot slower than the rear carb.  That one drops in about 5 seconds, the other one is almost double that.  Guess I'll have to see if I bent the needle or something later.  I'm sure it'll at least run, which is all I'm trying to do right now.

 

So then I tried to get the fuel pump relay situation started.  I took off the oil pressure sending unit and tried my best to thread in a 1/8 FIP T fitting, but it just wouldn't go in.  The female side of the fitting works fine.  I can thread in the sending unit into the fitting perfectly.  I'm going to try another one, as I'm suspecting I got a chinese defect.  

 

I also took the air pump off so I can clean things up a bit in the engine bay.

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Edited by juggernautjoee
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Posted (edited)

Got the electric pump wired up.  After finding multiple leaks and tightening them up, we've got fuel to the carbs now.  My garage is gonna smell like gas for a month, but oh well.

 

New spark plugs, egr deleted, capped off all the open vacuum ports I could find.  New small fuel lines from bowl to jet.  New filters in the banjo fittings in the float bowl.

 

But now the car won't start.  I know that's my own fault for changing a thousand things simultaneously.  But the way the weather is around here, I have to cram in as much stuff as I can in one day.  

 

I can squeeze the float fuel line and see some fuel bubble up into the jet/carb inlet area.  I believe I set the float correctly.  I used a 9/16th spacer and blew into the needle valve.  I adjusted the little metal bracket to just start closing the needle when it touched. 

 

I need to get some real starter fluid tomorrow to help me narrow down if it's fuel or spark related.  I tried with some brake cleaner, and it barked off a couple times, but not enough to get it running.  

 

I do have the 280z distributor with the ignition control module in the passenger floorboard.  I'll need to read the FSM on a 77-78 280 to see if it uses things like the coolant temp sensor (broken wires coming from that) or something like that.  Or if it's simply just takes the signal from the magnetic pickup in the distributor and tells it when to spark.

Edited by juggernautjoee
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I took each spark plug out with the wire attached, set it down where the threads could ground, and we got spark on all 6.  It's a bit intermittent and weak.  So I'll start with the cheap cap/rotor combo first.  Even when I spray starting fluid down the carbs, it's not enough to get it running.  It maybe tries to fire 1 cylinder every 3-4 seconds of cranking.  

 

One thing that may be opening a large can of worms is.. When I had cylinder 5 open and cranking, some water sprayed out.  Not a huge amount, but enough for me to notice.  I also saw a pool of water out the backside of the tailpipe after I'd been cranking on it for awhile.  Now it has been fluctuating temperatures outside like crazy over the past few weeks, so I know there is going to be a bit of condensation in those exhaust pipes.  But I don't want it to be a bad head gasket, or worse, a cracked head/block.  I'll just do the right thing and ignore it for now, lol.

 

If the new cap/rotor doesn't at least improve the chance of starting, I'm going to be looking at Pertronix ignition module and coil to get rid of this ballast resistor and old ignition module.  Hopefully that kit works with my 280z dist.

Edited by juggernautjoee
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No need to do a compression test.

 

I filled the radiator full of cheap coolant last night.  

 

Took the #5 spark plug out this afternoon and water was completely filled in the cylinder.  Guess I get to tear down to the short block now.

 

Crossing my fingers that it's just a bad head gasket.  If it's a cracked head, then I guess I'll see what my options are there.  Shaved P90, etc...

 

If it's a cracked block, then it's time for an LS

Edited by juggernautjoee
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