Sputtering when throttle applied ... what gives?

[Zorro]

truck is a '94 4.0L, 130k mi, 4x4 if that makes any difference. I also swapped to a manual transmission a couple months ago, and I did swap the ecu as well.

Coming back from work (15min), it started sputtering towards the end of the drive. It would sputter if more than 1/4 throttle was applied (or thereabouts), but do fine as long as I wasn't stepping on it.

Back home, I checked the plugs, they're white, fuel starvation.

Could it be the fuel filter? fuel pump? injectors?

I'm not out of gas, gauge says I'm half full ... although I tried adding a gallon (from a little red one gallon tank, not gas pump) ... and it overflowed after half a gallon. No idea where that came from, but there was no way to get any more in ... and I'm positive it's nowhere near that full.

Bottom line ... help out a pour soul out there

TIA

 

[JohnPi]

I had a similar problem on my '93. Fuel Filter. Something worth checking into, if you don't know the last time it was changed.

 

[289-tiger-]

overflow of gas on a half empty tank would indicate a twist or kink in the internal filler hose (don't know if you replaced the notorious cracking filler hose on 94's)fishing a flexible tube down the filler pipe would find that.
Check fuel pressure at the rail.
The MAF will also give you the issue without throwing a CEL.

Good luck

 

[Big Jim M]

Fuel filter can cause the sputtering...but usually starts at high speed and is easily recognisable.
Also sparks and wires can cause sputtering under a load..
Big JIm

 

[Zorro]

I must be blind ... I've looked at the manual 5 times now ... and there is no mention of any fuel filter anywhere. Uh?

I will clean the MAF, see if it changes anything.

 

[86_cookiemonster]

Did you check the plug wires? I know my ranger and taurus started acting up like that when the plug wires started to go bad.

 

[AllanD]

On a 1994?


Drivers side frame rail.
Right about even with the rear rivet for the radius arm bracket

You'll need a RED fuel line disconnect tool to replace it.

AD

 

[289-tiger-]

On a 1994?


Drivers side frame rail.
Right about even with the rear rivet for the radius arm bracket

You'll need a RED fuel line disconnect tool to replace it.

AD

Actually, on the 94 Ranger 4L to replace the fuel filter it should be attached to the lines by simple nylon "hairpins" that should be replaced after removal, most auto part stores carry these. A screwdriver will do to remove. Don't forget to depressurize the system.

Good luck

 

[Greg5567]

you may need to replace injectors....i have the exact problem in my truck
94 Ford Ranger XLT 4x4 and the injectors need to be replaced, mine sputters if i put to much gas on it to fast, i think i can slowly put my foot down harder the faster im going but from a dead stop if i floor it i sometimes stall?

 

[Zorro]

Ok, fuel filter did not fix the problem. Thx Allan ... can't believe I couldn't find a word on fuel filter location in the manual! 289 tiger you are correct, it was just little plastic pins.

I'm going to check the fuel pressure now ... a faulty fuel pump would give an erratic or wrong reading, I assume.

I just want to go through all the fuel related issues first, as the spark plugs are white (sign of too poor air/fuel mix, ie not enough fuel).

Unless it's just the MAF ...

aargh.

 

[Zorro]

I put in new spark plugs ... and problem's gone! One of the plugs was broken, but I couldn't tell if I'd broken it while removing it, or if it was already broken.
Works fine now!

However I did check fuel pressure, and it's pretty low, oscillating between 15-20psi ... is the fuel pump on its way?

 

[289-tiger-]

Fuel pressure should be 35-45 p.s.i. key on engine off steady. You may have found your lean fuel issue. If you determine it is the pump, it is a lot easier to pull the bed and not drop the tank. (3 screws at filler, disconnect taillight harness and unscrew the bed bolts and remove bed)

Check electrical to pump before taking the plunge for a new pump.

Good luck Sir.

 

[Zorro]

Are you saying the wiring to the pump could be at fault?

As far as reaching the pump ... I'm not sure removing that bed is as easy as you make it sound. I'm in Canada, which means every single bolt will most likely have to be torched off ...

 

[289-tiger-]

Yes, corroded or bad connections are possible, just a good thing to check.

Try loosening and retightening the 6 torx bed bolts and the 3 filler screws to see if anything is siezed up. The connector to the lights is below the tailgate. You will need a friend or a "come along" to raise the bed. Would not recommend torching the filler screws

If corrosion is that bad and pump is faulty you will need a new locking ring for the pump.

This method allows you to stay on your feet during the job.

Good luck

 

[UrbanRedneckKid]

You will not need a new locking ring for the fuel pump. It has a giant plastic ring/nut that screws to the top of the tank. Just buy a pump, it comes with all the seals, hose, clamps, and screen.

Only use Carter or Ford fuel pumps, anything else is junk.

My truck was running lean, just as yours is. Had the same fuel pressure your does. Then a week later, there i was putting a pump in it.

FYI, it is a waste of time to put a new fuel pump in without completely emptying the tank and cleaning the hell out of it. you must make sure there is absoultely no dirt in the tank, that screen on the bottom of the pump does almost nothing (but that doesn't mean to leave it out) Good Luck