1987 jeep cherokee fuel and no start problem

i have a 1987 jeep cherokee with inline 6 and multi port injection.

some time this vehicle only starts when hot
some times only when it cold

i have recently fixed the fuel leak.

when its hot or cold and not starting if i relieve the fuel pressure at the fuel rail, in most cases it will start imediatly.

however if fuel pressure relief does not work. i disconect the vacum line at the what looks to be the EGR valve or the pressure regulator at the front end of the rail, then usually starts right away.

i have not tested at this time to see if the fuel pump is failing nor have i tested fuel pressure.

I have read through alot of the forms here ot some ideas but im trying to narrow down the problem to one specific part.

there is no problems with cranking.
there is spark - coil, plug, dist cap have beeen replaced.

it seems the problem is with fuel delivery of sorts.

it was mentioned that sometimes the heat from the engine could be heating the fuel rail to a point which turns the fuel into a gas not allowing it to atomize.

any help in this matter would grewatly be appreciated

step 1 you need to read fuel pressure and know what it is doing at no start either fuel pressure is present are not. if you don`t have pressure it could have leaked down and engine is flooded and pulling that vacumn line off is just giving more air. test fuel pressure and go from there otherwise we can just keep guessing all day? good luck let us know what ya find. signed, always stuck in diagnostics

Mathew

Alright i tested fuel pressure and well it is running its around 40psi

tested pressure well in accesory mode lands around 18 psi

currently i have pllugged both end of the fuel pressure regulator to see if that curbs the problem, if so i think i may need a regulator

Have you fixed this yet? The spec on fuel pressure is 31 psi with the vacuum line attached and engine running. It's 39psi with the vacuum line off.

Was the engine running when you got 18psi?