bsummit

I noticed my fuel pressure was getting low and was thinking it might be the electric sending unit going bad so I got a filled gauge and hooked up direct under the hood and got the same readings. 3 to 5lbs of pressure. Well at this point I said change the lift pump and thats what I did. Now I don't have any fuel pressure and the pump has lost it's prime. I took the top off the filter and tapped the started to see if the pump was working, and it is. I got fuel all over everything, but when I put the cap back on the filter and cycled the pump, I still don't have any pressure. Could I have something hooked up wrong and what is the best way to prime the pump. i know I got to get the pump working first. It's just been a bad day. I got to try and get it running by noon tomorrow. This is the second lift pump in 85K miles. Could the pump be sucking air somewhere?

J Lent

Sounds like a air lock....if it works without the cap, but not with the cap on. Just crack open the fuel lines on cylinders #3, #4 & bump the starter....you will here the pump run. While the pump is running tighten the lines after all air is out & only fuel is coming out.

bsummit

Thanks J Lent, I'll try that in the morning. Will let you know if it works.

bsummit

Ok I'm back in business. I bled the low pressure line at the injector pump and it started on the 3rd try. I have fuel pressure now. With a new lift pump the pressure is not as high as with the last pump. It's holding at about 12lb. I guess I can't complain, better than 3lb.
Thanks again J Lent.

bsummit

Ok my fuel pressure has settled in at 10lbs which is low for a new pump. Could I still have an air leak some where in the fuel line? And if so, where would I start looking first..?

Sea:\>Drive

Drive it for a bit. I have an electric gauge and recently put in a Holley Black and had all kinds of weird readings. Changed out sender, dropped tank and cleaned, inserted clear line to look for air, mulitple manual gauges to compare readings, then gave up.

I stopped being hung up on the numbers, and just use it to look for consistency. Mine had settled to around 12psi @ idle and no less than 9.5 @ WOT. Then the other day I look over and she's running at 14psi while I'm doing 70 down the highway...

knjnf

Hey...I just replaced my second lift pump yesterday. First one at about 85k and this new one at 158k. Bleeding lines has always been a problem. I also found out that my fuel gage is wrong. 1/4 tank is empty.

Always carry a fresh fuel filter and a 17mm and 19mm wrench.

JOHN