Got a 1986 Ranger 2.3 EFI 5 speed that I have owned since it was almost new and will never let it go. 290,000 mls and still running strong "except". Noticed the last couple of months that when I start it cold it fires right off. If I start it hot it always takes 3 tries and always goes on the third try except....on occasion it will not start at all. It is random and after I let it cool a bit (about 30 min) it will start. Over the years I have replace many of the fuel system components (fuel tank pump, high press. pump, inline filter and canister filter, fuel press regulator) but wondering what else might be the problem. I put a pressure tester on it the other day and when I selected the key to start the pump would spool up to build pressure and shut off. The press guage would register that but the pressure would immediately go back to zero. After start up it would hold a constant 30psi at all rpm,s. Shut the engine off and pressure drops right down to zero. Shouldn't the system hold pressure for at least a while after shut down? Could this be the problem with my sluggish starts? What would be the normal fuel pressure? Can't seem to find it in my Haynes manual. Once running it runs great. What do you guy's think. Thanks for any help.

 

dont know about your year but if its an elec pump and in tank, you could have a bad relay or one with corrosion on contacts. Thee mid 90's had a lot that had relay problems and would start much like yours after sitting. If it has a relay, change it out.

 

Should be 40 PSI KOEO. When I had the same problem the pressure was also at 30 & it dropped like a rock when I shut the engine off. It was hard to start, but no smoke once it did start.

If yours is not smoking when it starts it's probably the same problem as mine a bad check valve in the frame mount fuel pump. If it is smoking might be a leaky injector or pressure reg.

Congrats on keeping that good old Ranger on the road.

I have 240,000 miles on my 87 and still going strong.

 

I was thinking there had to be a check valve in the system some where to hold the pressure after shut down but couldn't find a schematic that showed one. Didn't realize it was in the high pressure pump. Mine does not smoke after I start it. The pressure does drop like a rock when I turn the key off. I guess the only fix is to replace the pump.

 

Yeah, it does sound like the pump

 

Lets think about this some more, as you may have more than one problem.

When the engine is cold, will it hold fuel pressure after you turn the ignition switch from off to run, long enough for the fuel pumps to run & cycle off????

When it acts out warm & won't restart, cycle the ignition switch from off to run, (but don't crank the engine), say 3-4 times, pausing at run long enough, say 2-3 seconds each time until the pump/s run & cycle off, Then crank the engine. If it'll immediately start & run, suspect a fuel pump problem. Seeing as how yours has two pumps & you don't seem to have been having power problems as you drive, it sorta sounds like the in tank low pressure feed pump belongs low down on the suspect list for now & I agree the high pressure fame rail mounted high pressure fuel pump belongs higher up on the suspect list.

Additionally, if you have a return type fuel system, that has the fuel rail mounted pressure regulator, also put it on your suspect list, maybe along with a leaky fuel injector/s. Remove the pressure regulator vacuum line to determine if its damp, or wet inside with fuel, if so, the regulator diaphragm is weeping/leaking fuel into the intake manifold & fuel pressure will bleed off when the engine is shut down. Same for a leaky fuel injector/s. If the fuel injectors have a runny nose, or the pressure regulator diaphragm is leaking fuel, the plugs should show carbon fouling evidence on the internal ceramic insulator & maybe the center & ground electrodes & as has been said, you may see restart evidence in the exhaust of a rich air/fuel mixture. If the fuel injectors are leaking, you should also be able to sniff the oil dipstick & if it reeks of raw fuel, the injectors or a leaking fuel pressure regulator diaphragm belong on the suspect list.

More thoughts for pondering, let us know how it goes.

 

Thanks pawpaw for the advise. All good stuff and easy to check. The injectors have never been out of the vehicle so they may very well been worn. I replaced the pressure regulator a couple years ago. I'm out of town for a few days but when I get back I will get right on it.