losing prime
 

Help, I have a 96 jimmy. My truck will turn over but will not crank. I have to crank off starting fluid. After I get it cranked it runs fine, no miss or anything. The thing that gets me if I turn switch off and immediatly turn back on it cranks. If I let is sit for a overnight or while I am at work I have to crank off starting fluid. I have replaced the fuel filter, distributor cap and rotor button. This is my families only vehicle so I have to get it fixed fast. Thanks

RE: losing prime
 

Do you hear the fuel pump run when you turn the key to the On position?

If you crank it for a while, will it fire up? (crank means the engine turns over, but, no internal combustion noises, in this case.)

Can you check your fuel pressure?

How many miles on it?

RE: losing prime
 

got 140,000 miles. I dont have the tools to check fuel pressure. But I will go outside and see if i hear the fuel pump running.

RE: losing prime
 

at first if i cranked it for a while it would start up. Now it has gotten worse. It will only crank on ether. If I start it, run it for a while and cut it off it will start. If i let it sit for four hours or more it will not start unless i use ether

RE: losing prime
 

Theres 3 things that make an engine run...

Spark / Air / Fuel....

If it starts when you add starting fluid, that means your not getting fuel and your fuel pump is not pumping fuel when the key cranks.

Check the fuel presure with the Key on Engine Off it should be around 58-60psi

RE: losing prime
 

thanks for your help. i will get a pressure tool and check in the morning.

RE: losing prime
 

I am really thinking fuel pump relay here. But, I am curious to see this one fixed, and what it was.

RE: losing prime
 

which relay is the fuel pump. I know there are three in the glove box. which one is it

RE: losing prime
 

I think it is marked F-pump

RE: losing prime
 

If you've gotten the fuel pressure gauge, then good, because I'm voting for either a bad fuel pressure regulator or bad fuel pump. Hook the gauge to the schraeder valve on the fuel inlet line above the engine, with the key in the 'on' position you should see 55-62psi. Turn the key off and the pressure should not drop more then ~2psi. Let us know.