95 ranger 4.0 won't stay running

[Kennedy11]

I have a 95 ford ranger xlt 4.0 v6 with 188,000 miles. I drove to the store, when I came back out I went to start it and it backfired or what sounded like it. The truck will now only turn over and rise to 4000 rpms and then stalls out. It seems like it's starved for fuel. It has a new fuel pump, new plugs and wires, new coil pack and new battery. Any ideas? I need help i can't figure it out. The truck has had no problems to now. Thanks!

 

[RonD]

Not clear about starting?
You crank the engine, its starts, and it revs to 4,000rpms on it's own then dies.

But will restart right after and do the same thing, if it restarts it is not a fuel issue

If this is the case it sounds like the "back fire" blew off a hose, PVC hose, Power brake hose, or intake gasket.

Computer opens a small "air leak"(IAC valve) to set RPM from 750-1,500rpms, a big air leak will run RPM up to 3,500-4,000rpm before "rev limiter" will kick in.

 

[Kennedy11]

Well when it turns over it continues to backfire and spit and sputter then stall out

 

[RonD]

When did you last get gas?
If it was just before this issue then there could have been water in the gas.
Water settles to the bottom of the fuel tank and fouls the mix.

On another note, I would check compression in all cylinders.
Remove all spark plugs first!
Cold engine is fine.
Crank engine, you should get 165-175psi on each cylinder

Thinking maybe a timing chain issue if compression is coming in at 120-130psi
Base spark timing comes from the crank(CKP) sensor, if cam(valves) are out of time because of timing chain tensioner issue you could get the backfire, plug sparks while intake valve is still open and general no run issue because of low compression.
If you remove a valve cover and watch an open valve while you manually turn the crank one way then the other way you can tell if chain is loose, cam should turn with crank, no lag.

 

[Kennedy11]

I had gotten gas about a week before this happened. The truck currently has a 1/4 tank of gas. I did try adding heet to dry any water out of the gas but it didn't clear anything up. The compression is good, it has good spark as well. When I spray carb cleaner down the the intake manifold it will run for a little bit but not long it usually stalls after about a minute this why I think it to be fuel issue however I'm pretty much at a loss, the inertia switch appears ok, has a new fuel pump now, I did not change the fuel filter though but I've never known them to be so clogged that they prohibit fuel flow

 

[black_demon69]

need to check fuel pressure i believe it should be 30 to 40 psi if i remember also need to check injector pulse. what brand of fuel pump did you put in? if it is an airtex replace it they are junk. one more note i would replace fuel filter just to rule it out also it is cheap and good maintenance.

 

[RonD]

Week is too long ago, bad gas is noticed the next day or sooner depending on running time.

Dirty fuel filter shouldn't prevent idling, higher rpms yes.
But that being said for the $10 I would change it just to take that issue off the table.
Because yes, if it is dirty enough can limit pressure.
Turn key on, count to 3, then turn key off(you should hear fuel pump should come on for 2 seconds)
Repeat this 3 times, that will build up pressure in the rail.
Now try to start.

Also on the fuel rail is the Fuel Pressure Regulator(FPR), it has a vacuum line attached, check that vacuum line for gasoline or gas smell, replace FPR if fuel is found in that line.

How are you spraying carb cleaner into the intake?
If you disconnect the air plenum(big plastic tube on intake) then the MAF sensor would be off line, so computer wouldn't be operating injectors correctly.
I would disconnect MAF sensor wires if you are doing that, this tells computer to run base fuel mix based on RPM not air flow, CEL will come on, which is fine, it will go off when MAF is hooked back up.

 

[Kennedy11]

Could these issues be a result of a bad crank sensor or cam sensor? As far as spraying the carb cleaner into the intake manifold I'm just unhooking the black rubber tube that connects right to the manifold and spraying down in then then putting the tube back on

 

[Kennedy11]

Fuel filter disconnect won't disconnect

Trying to change fuel filter on 95 ranger 4.0 the quick disconnect will not let go. I'm using the plastic quick disconnect tools any suggestions?

 

[Kennedy11]

Fuel filter changed problem still exists

 

[RonD]

Fuel filter was a long shot but not a 0 shot, like air filter or oil filter it just needs changing now and then.

Crank(CKP) sensor failing will cause a no start, not rough start, and never ran across an intermittent one. CKP sensor sets base spark timing.
Cam sensor(CPS) failing shouldn't cause your symptoms, it sets injector timing and some spark timing at above idle RPMs, but computer would ignore odd CPS data and use Batch fire until data made 'sense', it would also turn on CEL(check engine light), if CPS or CKP sensor wasn't working correctly.

So I think you are looking for a mechanical issue.
Some "new" fuel pumps, non-Ford brands, have been known to fail within 30 days of installation.

How did the "key on 3 times" test work?

 

[Kennedy11]

Could it be a bad fuel pressure regulator? And do you know where it's located?

 

[Kennedy11]

The key on test 3 times didn't help either.

 

[SenorNoob]

Might be a stupid question but are you SURE it doesn't have a major vacuum leak?