I'm not getting fuel to the carbs

[mdixon]

I have a 71 240z. I replaced my manifold with 6 to 2 headers, got a new exaust, re-built my carbs and pluged all the smog stuff on my balance tube.

Now I'm real excited to hear this new exaust. Well geuss what, It wont start.

First I take my fuel line from the gas tank and put it in a gas can to see if there is a block up to that point.

Still no gas.

Then I take the fuel line off the carb and turn the engine over. No gas. So I blow through the line and air seems to go through.

So I buy a new fuel pump. (mechanical)

Well geuss what, you have to take the whole air compressor off to get the fuel pump off. (needed to clean that area anyway)

New fuel pump on, still no gas.

What should I do Now????

By the way, I did take the tops off the fuel bowls and add gas. The car ran for about 45 seconds and sounded great.

[Fun_in_my_z]

Whens the last time you cleaned the tank? There could be somthing blocking it up.

Is air coming through the line from the tank to the cabs? Could be stopped up fuel line.

[AxtellZ]

I thinks i'm confuzed:ermm:

You pulled lines where=no gas?

I'd start behind the new mechanical pump (between the pump & the tank). Drop the line that goes into the pump in a container of fuel- Does it draw fuel from that container? If it does, the blockage would be between the pump & tank.

If not- your mech pump is bad (shouldn't be if new!) or theres a blockage from pump to carbs. Did you check the floats, or needles in the carbs? Filter screens in the banjo fittings on the float bowls? Will fuel (or air) flow from the pump, to the inlet of the carb bowls?

As i reread your post, it seems your tank pickup may not be feeding gas- if thats the case though, it should work fine feeding from another fuel container into the pump...

It's gotta be something simple- let us know.

JA

[mdixon]

Thanks guys,

I disconnected the fuel line at the top of the carb to watch if gas was flowing.

I did take the fuel line from the tank to the pump and stuck it in a gas can. (gas can to pump) no gas flowing.

I replaced the fuel pump. tried the same thing, still no gas flow.

I guess my fuel rail is blocked, but I was able to blow backwards from the hose that connects to the carb.

I thought maybe someone might have had this same problem.

[Bruce Palmer]

... and see if you can pull fuel at the inlet side of the fuel pump. Smells like a tank problem. I've seen some pretty scarey stuff in Datsun gas tanks. Bottle caps, rocks, sticks, etc. etc.

Am hearing more about rust etc. in these 30 something year old tanks causing big blockage problems. One guy on the 510 list flat had the bottom of his tank rust through. Scaley rust developing, breaking loose and moving around could certainly block tank outlets.

[AxtellZ]

Hmmmm.

Not sure if the pump would need to be "primed"- don't *think* so, but maybe it won't draw if its totally dry.....

When you blew air into the line entering the carb- did it flow through the rail & back to the pump (could you hear/feel it there?) Or did it just blow up & out to the other carb?? That would indicate a blockage from pump to rail, or early in the rail itself i'd think..

[mdixon]

I disconnected the tank. I am using a 2.5 gallon gas can. I still have no fuel going to the carbs.

What I don't understand is before I re-built the carbs, I had no problem with the fuel getting to the carbs.

It has to be the fuel rail. That is the only thing between the gas can and the carb. except the fuel pump, which i just replaced.

But I can blow air through the fuel rail.

Don't understand why I can blow air through the rail but cant get gas through there.

[mdixon]

Actually, I had the front carb still connected. I blew from the rear carb fuel hose.

I could hear it coming out at the fuel pump.

[AxtellZ]

Huh.

Been a few years since i replaced a mech pump- is there anyway the actuating lever that makes it pump is out of whack, and not contacting the cam to pump properly???

When you crank the engine, with the fuel line removed at the pump, can you hear it "sucking"? No pun intened there, folks.

I'm stumped, i need some coffee to think this out some more!

[kmack]

Originally posted by mdixon

What I don't understand is before I re-built the carbs, I had no problem with the fuel getting to the carbs.

Check your float level. If the carbs and everything else was working fine before you rebuilt them, then maybe you inadvertantly adjusted the float level so that the float valves are staying closed and not letting fuel in. You did say that you removed the floats and added gas and the car ran. Was there gas in the float bowls when you first opened them?

Try this: Disconnect the small rubber line between the fuel pump and the fuel rail. Does gas flow? If yes, continue to next step. If no, Fuel pump.

Now disconnect the fuel lines from the fuel rail to the carb float bowls. Both of them. Does gas flow? If yes, then continue. If no, blockage in fuel rail.

Disconnect fuel lines between float bowl and choke nozzle (bottom of carb.). Does gas flow? If yes, possible blockage in nozzle. If no, float is sticking or staying closed.

You have to be methodical in the process. Go step by step, section by section. And ONLY change one thing at a time!

My guess right now is that it's in your floats. But if you follow these steps, you'll find it. It's definitely fuel related so at least you only have one system to check! :classic:

[Fun_in_my_z]

Not to be rude or to try and call you domb. But i have seen cases like this before that the vehicle didnt have any gas in it.

Does your?

[mdixon]

empty gas tank!! Yes I thought about that. It wasnt my first thought, so I thought I might be that dumb. But that was not the problem.

When I opened the float bowls they were bone dry. But I did check to see if gas was even getting to that point, and it is not.

That is why I replaced the pump.

I must have a block in the fuel line.