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New guy, New problem


Beau_

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I just picked up a new to me 73 240. It has roundtop 3 screw SU's.

 

Heres my issue.

The slave cylinder busted one night, so I towed it home. The next day while replacing it, I noticed a pool of gas under the gas tank. The vent line that runs off of the driver side of the gas tank was frayed, badly. I, then replaced it with the same size heater hose and made sure all the clamps where tight. Took it for a spin and didnt get out of the driveway. i have to keep the revs above 3k to get it move, then it will just bog down and die.

 

Fuel filter was replaced and I checked the psi at the pump. 3.5 psi. Pulled the plugs and they were black.(I had just bought them) Checked for vacuum leaks and didnt find any.

 

It was running fine until I changed this hose. I drove it home the day I bought it and for a good week until the slave cylinder went out.

 

Any info on why it wont run under load would be awesome.

 

Thanks in advance

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I can sympathize with the busted slave cylinder and fuel vent lines.

You need official fuel line/vent hoses though ;)

 

Check your fuel return line that it isn't busted.

Change ALL fuel filters... then try...

Change/drain the gas .... water ???

 

Still no go ? Clean your piston domes in your su's (they get mucked up ) and fill with appropriate oil.

Check your float levels and condition of floats.

Sync and tune your su's

Change/inspect air filter.

Check for vacuum leaks.

Set timing

Turn chokes on (needed)

 

I change fuel filters about every 6 months.

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 I, then replaced it with the same size heater hose

 

This is not your current problem.. but it will be a problem in the future.. Use fuel grade hose. heater hose will deteriorate.

 

good luck on your search for "Datsuness"   (good running and driving Datsun)

 

Mike

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Thank for the info.

 

I forgot to mention. I replaced my points, gapped to .016. Set the timing at 17 degrees at 650. Still same problem. Took my carbs off to inspect them. Doesnt seem to be gunked up.

 

My question is, is there anymore fuel filters in the system, besides in the carbs and in the bay? Would the fuel sending unit have anything to do with it?

Could the vent line create a vacuum? If there was a vacuum leak, would I still get 3.5 pounds?

 

Im stumped

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Look at your dizzy cap and points/condensor connections extremley close,y about 10 times.. :)

Especially the wires leading IN and OUT of the distributor as well as condensor.

Replace the condensor if you have not done so.

Re-check point gap very carefully :)

 

Sooooooo many problems have been a result of ign mistaken for fuel and vica versa.

My 73 240z with su's ... would cut out (like fuel suspicion) ...

But end up being carbon tracking inside the distributor cap...

My solution was to rev it up and push it until I got home (not abuse)

 

EI conversions are very worth it. (E12-80 module... entire distributor from a 79-81 na 280zx ... a few wires to hook up.)

Cheapo replacement ign components never really last with older equipment.

 

There sometimes are fuel filters just in front of the gas tank ...

All of these cars have been touched so its hard to know.

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Sorry, forgot to mention I replaced the condensor as well. The good thing about this car is parts are cheap. I think I might go electric ignition when I get the carbs back on.

 

I just dont understand it. It was running fine until I changed that hose.

 

Im going to start pulling my hair out.

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Understandable haha.

 

Run a seperate small temp fuel tank

If it solves the problem great !

If not.. look elsewhere :)

 

Did you replace the distributor cap and rotor or clean them at least ?

 

Condensors,thermostats,light bulbs , etc can ALL be bad out of the box !!

I've had that happen to enough to know to not trust anything until its proven...

*insert paranoia*

 

Also.. if it was running fine before put your old condensor back on and try it !

:)

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It is a coincidence. Nothing to understand, really.

 

So it had the same symptoms using the old points & condensor? And a new points & condensor didn't help.

 

 

> i have to keep the revs above 3k to get it move, then it will just bog down and die.

 

Could be many things. I would start by checking the Float Levels.

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:rofl: noooooooooo hahaha

 

Do the condensor switch as well ;)

 

The rear breather hose you replaced ... by chance the one in the very rear with a SHARP bend at the tank ?

 

Ztherapy ... in salem,or .... will re-build and repair/clean your su's for about $750 a pair ? Last I checked.

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The level of fuel in the float chamber can be checked through a circular window located behind carburetor. It is necessary to use a mirror to inspect the fuel level. The level when engine is running should be midway on the glass. If instead the fuel is completely covering the glass, that would explain the overly rich running and bogging down.

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Haha, for the most part. I dont feel like I might fall into a deep sleep that I might never wake up from anymore.

 

By the way, Im looking at the dizzy upgrade right now. Any good write ups on the installation and parts list? Just a dizzy out of a 280z right?

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Don't mess around with distributors at a time like this. Find the problem and fix it.

 

Points distributors work well, the only problem is the points & condensor need to be changed every 12k miles. If you suspect the distributor, test it for spark. It's free and it's easy, so test it.

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Haha, for the most part. I dont feel like I might fall into a deep sleep that I might never wake up from anymore.

 

By the way, Im looking at the dizzy upgrade right now. Any good write ups on the installation and parts list? Just a dizzy out of a 280z right?

 

It would be a good way to go lol.

 

79-81 280zx non-turbo.

E12-80 module (on the side of distributor)

Also known as a "matchbox"

If you find one with more than 2-prongs (at the top for wires) its the wrong one lol

I'll see if I can find a link that explains faster than my long replys lol.

 

Pm'd ya

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.

Don't mess around with distributors at a time like this.

 

I wont, aleast not until I get the carbs back on the car. I just want to make sure Im going through all the steps correctly. Points gapped, timing set, correct fuel pressure.

 

Is there anything Im missing. I know its simple. Just fuel, air, and spark....Well, I guess, a little luck. Haha

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I put a battery in mine and it fired up with a little "caress " I drove it about 13 miles to my house costing because I didn't want to beat my motor up to bad because I heard a small knock but it would get going pretty good for a couple hundred yards then bog again but I could only get her to about 25 MPH:/ can't wait to get my new motor and trany so by by natural aspiration hello super:D I'll be posting pic in may or June when I get the beast! And check out accel they have point to electric concretions but I don't know about datsuns for sure I used it on my 289 and it was worth it and didn't take too much time to install

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ill have to look into.

 

By the way, whats my options on radiators? Mine went on a date with my fan. Then the one I bought off line deiced to leak out the bottom. Ive seen some ebay specials, but heard some bad things.

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Ehhh....ALL 100% aluminum radiators in my opinion should stay on racing stuff.

Unless you have no options or got a great deal on one that's going to cool much MUCH better than stock.

I love them as much as the next guy. Unless racing your engine a bit or bored out and stroked engine (thinner walls) then yes ! If it fits the purpose.

 

I'd just make sure you have your mig spool gun , tig , epoxy or whatever in an emergency kit if you do lol.

 

They're probably fine and all probably come from 5-6 different sections of the same factory lol

 

Money best spent elsewhere first if it were me.

 

Grab a zx radiator local ... convert to electric fan and be happy !

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