another non starting truck,seem to have the same air leak in fuel system,i have needed to slacken open the first injector to get truck started,this is ater installing a mechanical fuel pump,had some screws missing where the injector pump was,got those back in and tight,below that on the fuel line theres a brass plug,maybe a filter in there,dont know,now could i have a leak in the line at the tank,im getting a air block in there somewhere,been good for a month,now happened again,any ideas.

 

What year truck?

 

1993 with cummins,if i try some snoop or soapy water to detect a leak should i have the truck running or should i pre spray it then try looking for the leak while i crank it over

 

Soap probably won't do it. Look for an oily spot on the fuel supply and return lines. Have you changed the fuel filter lately, or opened the fuel system up anywhere? I'd inspect that spot first if you did.

 

i put in new mech, fuel pump,had bolts missing in injector pump,theryr all tight now,but if i have to slacken off an injector to get the fuel moving ,would my leak be somewhere up front of the fuel filter ,could the diafram in the injectr pump be toast,maybe distorted or damaged, ive started my truck without problem every day for the last week now,seems ok,still get killer milage

 

The best way to find a fuel leak is to blow a little air pressure into the fuel tank and look for leaks in the lines. The lines are normally under suction, and a little pressure in the tank turns those invisible air leaks into drips of fuel.

 

k,thanks WD,i'll try that angle next

 

on each fuel line at the nut where there is the compression fitting,there is a sleeve around each line where the nut slides over and then threads onto its fitting, there is no sleeve on the fuel line on the top side of my mech, fuel pump, this is the nut i have had to loosen periodically to get the fuel movin,i suppose theres enough slack in there to cause a leak, does that sound possible,it would be the last place to check,ive looked over the entire fuel line system,no leaks visible

 

It sounds to me like you have a leak between the lift pump and the tank. Concentrate on those lines.