2.5L ('98-'01) Compression Low

[Theunknownstep123]

99 2.5 ranger 170k miles. Getting fuel and spark and have checked all systems over. It will not crank unless on starting fluid. Compression test with two kits yielded: Cylinder 1-165 Cylinder 2- 140 Cylinder 3- 90 Cylinder 4-155

Could the low compression in cylinder 3 be causing my no run issue. Is there a common problem with compression caused by valves or rings etc on this truck? Thanks!

 

[franklin2]

You have enough compression on the other cylinders for it to start. When you get it running on starting fluid, it runs ok with a slight lope maybe? Or it runs fine?

I would get a scanner on it and see what the coolant temp and the air intake temp sensors say. They should be close to ambient temp when starting a cold engine.

Once it's warmed up, does it start ok after that?

 

[Theunknownstep123]

It won’t stay started, it’ll only run for a moment on the fluid and die once it’s all used up. Haven’t been able to keep it running. It’s been sitting a long time, replaced crank sensor and changed pump, filter and cleaned injectors. Once I did all of this it ran for about 30 seconds and ran well until it bogged down and died. I haven’t been able to keep it running unless using starting fluid since. Would not start at all even with fluid before changing crank sensor.

I do have a good scan tool and can check all the sensors soon. It does just seem to be a fuel issue

 

[pjtoledo]

what is the fuel pressure with key on before starting?

15-20 psi is a "has fuel" but it isn't enough fuel to run, so we need the numbers please.

 

[rusty ol ranger]

For sure check pressure.

You replaced the filter pump and injectors...so thats good.

Its firing on ether so it sounds like the ignition is working.

90 psi is low but i wouldnt obess over it espicially if its been sitting. 90 is actually, should be enough to fire that cylinder and for sure the other 3 are. That cylinder might even come up once you get it running correctly and the rings can move around.

That said...depending on how long it sat (after checking fuel pressure of course) you may need to drop the tank...there might be a bunch of shit in it and its blocking up the sock on the pickup tube.

Also...you have drained the tank and added fresh fuel right?

 

[Theunknownstep123]

Pressure is really good, when turning key to on position it sits right around 60 and stays. I did drain all of the old gas and filled with new.

 

[rusty ol ranger]

Pressure is really good, when turning key to on position it sits right around 60 and stays. I did drain all of the old gas and filled with new.

Leave your gauge hooked up and crank it and see if the gauge dances around that will tell you if the injectors are firing

 

[slater50]

Its not the low hole causing the issue...