Datsun Roadster Forum-311s.org

I have a 1970 2000 with a fuel issue.

History: carbs (early Solex) seemed to run lean up hills so I thought maybe not enough fuel pressure. So, I rebuilt pump. Now it won't pull fuel from tank, but it used to before I rebuilt pump.

I rebuilt the fuel pump and it seems to work. Pump would make suction noise when actuated in hand before installed in car. I put a line into a gas can and actuated pump by hand and fuel came flying out. So, that seemed to work. Next, I put a hose in a gas can and have that going to the filter which then goes the the pump then to carbs. It will pull fuel from gas can. I hooked at a 120v inflator (one of those fairly cheap ones to air up tires) and I took off the cover the fuel tank access cover and then the float thing in the tank and I can see it bubbling pretty decently. So, it appears that the line is clear. But, when I hook up line coming from tank to the pump,nothing. Fuel filter is brand new, and as I mentioned, it pulls fuel from gas can. And when I look into tank, it seems pretty clean in tank.

And I missing something? I have the fuel line clamps down pretty tight so I don't think it is sucking air. I'm stumped.

Try priming the fuel bowls with gas. Then be sure the bowl lids are tight with good gaskets. Also the fuel pump screws can work loose though you said pump worked in hand. Tiny cracks under clamps can be problematic. Good fuel bowl to nozzle hoses?
Good luck
Linda

I had a similar problem on my '67 a little while ago. It turned out to be the midpoint union with flare fittings. There was no drip but it was wet with gas. The nuts were tight so I loosened them and worked them back and forth a little then re-tightened. After that it sucked the gas right up

Okay, I jacked up my car to take a look at fuel lines. I also disconnected the hard fuel line in the engine bay going to the rubber fuel line which goes to filter. I didn't see any leaks or anything in the back of the car, so I went up to the front. That is when I noticed fuel dripping out the hard fuel line I had disconnected. So, just having the back of the car jacked up was enough to get fuel flowing. After a bit of cranking, car started up.

That would seem all is good. However, the car is exhibiting the same effects that caused me to think fuel pump was bad. What it does is "surge". It will flow fuel (well, fuel will bubble into filter) for about 10-20 seconds, then stop, then "surge" again, etc. It does this over and over. All fuel lines look good. I am using a brand new Nissan OEM fuel filter for my car (1970 2000). It is clear,so I can see the fuel surging. Previously, I had a white filter that i could not see in so I have no idea if this is normal activity for my car. I re-tightened all connections and I still have this issue.

Is this normal?

Okay, even though you swear everything is on tight and have new rubber fuel lines, I decided to put new rubber fuel line (again) going from hard line to filter. Yep,that did it. So I guess I didn't need to rebuild fuel pump, but at least that is done.

So, lesson is don't be an idiot like me. First thing to check is rubber fuel lines and replace. And check again and again.

Yah just never know! What a car teaches you is PERSISTENCE, and you figured it out! Glad to hear you're out running again.

A HF vacuum pump with tank on is my first test if it does not fill it up easy its got line/ tank probs

One other test you could do, is fuel pressure test, at the fuel line just before the carbs. Put a "T" fitting in the fuel line, just before the carbs on a R 16 engine, to test the pressure with engine running. Pressure should be 2 1/2 to 3 1/2 psi. Rubber fuel line leaks can be pain to find..... just replace all rubber fuel lines on older cars.

Fuel pump issues...... 1966 1600 OK New fuel pump, tested , sucks and pumps (3 Feet). Spacer plate installed fuel bowel clean and full of fuel, tank is full of fuel. Installed new pump.. got fuel to the pump...but the pump does not want to pump fuel out, when engine is cranked. Had pump off and on several times....no improvement. Checked the cam pump lobe... seams to be fine, no grove. The stroke on the lobe is 1/4 inch...best I could measure it. Thinking of adding a flat piece of flat metal to the pump arm... give 1/ 8 inch more travel. Measured the pump arm movement and there is plenty of arm stroke movement. The angel of the arm is the same as the old pump. Anyone ever had this fuel pump problem. Any help would be appreciated and get me on the road.. Thank you OU812

Don't add the piece to the arm. It will not give you a bit more stroke length. It will just move the stroke out of the diaphragm's range and probably cause it to tear. Quit looking for unusual problems and go over your connections again.

Thank you... yep that is what i've have started to do. Starting at the tank (supply) and working forward. Thank you OU812

Do you have the correct spacer between the block and the pump? There are At least two different thickness spacers out there.

Yes, I have the correct spacer. All seems good now (so far) as it appears that I may not have tightened all the hose clamps down enough (that's my best guess anyway).

My next issue (other than trying to figure out lean condition) is trying to get that o-ring installed back onto the fuel sender on top of the gas tank. I took it off to see if any tank issues, and now I am having a heck of a trying to get the fuel level sender installed back into the tank. I just can't get that metal ring (that hold the fuel sender onto the tank) to turn with that o-ring. I have tried using a long screwdriver and a few taps with a hammer, but the metal ring just won't budge. Grrr.

Clean things up, maybe a little WD40, screw driver and hammer to tap it around... it will go.

Back on the road..... Started at the fuel tank and worked forward... With a 54 year old car... it was time to replace some rubber fuel lines and clampe. Found a few rubber fuel lines that were weather cracked, cork gasket at fuel filter out of place.... all in all. Fuel pressure at carbs back to 2 1/2 psi. So back on the road.... Took the lady out for 30 mile run. Great. Thank you all for your input, Hope I can do the same some day. Thank you OU812