trafficnazzi

Hi, I just replaced the sending unit in the tank and now my 70 delta 88 wont start, I have spark. My original sending unit was a cannister type with a single feed tube. I installed a new unit with a vent tube that I blocked. Any thoughts? Could the pick up be too short, maybe they sent the wrong one?

oldcutlass

I moved your post to its very own thread instead of hijacking anothers. Since you have spark then I would look at your fuel system. Start with seeing if there is fuel at the fuel pump and go from there.

trafficnazzi

Sorry, I didn't know how to start a thread. The car ran fine in the fall. maybe the pickup isn't deep enough on this universal sending unit. But If I put more fuel in, then I have to syphin more out to drop the tank. I was hoping for air in the line. Is that common?

oldcutlass

Did you pull the line off to the pump to see if there is fuel coming out?

Tedd Thompson

You can pressurize the tank with a few pounds of pressure to get the fuel in the line and the air out try starting the car at the same time. Or just try a little fuel in the carb bowl and see if it fires up. Often this is enough to get the fuel flowing, sounds like a air lock to me. Try this with the gas cap loosened ... Tedd

trafficnazzi

Hi, I've done the fuel into the bowl and only after about 4 oz's does it try to start for a second. I'm just about to take off the line at the pump but I'm sure it will be dry. I'm tempted to put the original tall boy looking unit back into the tank. It worked except the fuel gauge didnt. I now think I could of just cleaned the ground and maybe the guage would of worked. thanks

MDchanic

Well, if you're certain, there's no need to troubleshoot, is there?

When you installed the new pickup, did you measure or otherwise confirm that the pickup sock was resting on the bottom of the tank?

- Eric

trafficnazzi

I compared the new sending unit to the old one but since the old one looks like a tall boy can, it wasnt much of a comparison since its hidden. I added more fuel and the guage moved accordingly so I think the pickup is deep enough. I just checked and replaced the 8 inch line connected to the inlet into the pump and its dry. I've ran out of fuel before and I've always just added gas and it started. Never had an air lock before. I think its time to replace the fuel pump.

joe_padavano

Before spending time and money on replacing the pump, have you tried filling the carb float bowl through the vent tube first? Often the issue is just losing prime. Once the engine is running, the pump usually starts pulling fuel from the tank. I use one of these solvent bottles to fill the carb, but a baby syringe also works.

MDchanic

What Joe said.

"Air lock" is not a thing that happens with these. Vapor lock, maybe, on rare occasions, if there's no return line.

Also, did you replace all of the rubber hoses and check the steel lines for pinhole leaks?

- Eric

frankr442

What's the brand and part # of the new sender? The return nipple should be a smaller diameter, but are you sure you're hooked up to the feed nipple?

trafficnazzi

Hi, no leaks at all. I guess it might just be that the fuel pump calfed over the winter. I'll replace the fuel pump today and let you know. I thought these pumps would last longer than 30,000 orig miles. I've never heard about priming the carb through the vent tube but do you know where this tube is located on a 2 barrell?

oldcutlass

If you have no fuel at the pump, it can't pump fuel to the carb. I'd wait on the fuel pump.

Octania

sounds like you hooked to the wrong line on the new sending unit. The size should have indicated which to use, but with replacement parts, assume NOTHING.

trafficnazzi

Proper line is hooked up.

MDchanic

He hasn't run it from a full float bowl, yet, so we don't know this.

FIRST, as Joe suggested, get a very small funnel or a syringe, or whatever, find the vent stack of the carb., and pour in gas until it starts to overflow.

In this picture, the vent stack of the 2-Jet is located in the bottom edge of the airhorn, sitting slightly diagonal, pointing toward the fuel inlet:





THEN give it a good crank and see if it'll run for 30 seconds or a minute.

If it stalls, fill it again. If you don't pull up gasoline from the tank in 2-3 tries, you're probably not going to, and other possibilities need to be investigated.

- Eric

trafficnazzi

Small tube is offset from the middle and the large feeder tube is in the center of the cap and leads to the sock. Large one is hooked up to the line going to the pump

trafficnazzi

ok thx, I'll try that just before installing the new pump

Octania

A new pump can't hurt
but it also won't help if the problem is the line hooked to the wrong tube at the tank.
or an air leak in the suction line, etc.


Always look FIRST at the last thing "fixed"


and related disturbed or affected items.