99 Ford Ranger sputters when lugging

ford
ranger
leaks

#1

My truck recently started sputtering while trying to accelerate, it runs fine at idle and at high RPMs. Had an error code of “Evaporative Emission Control System Leak Detected, Large Leak.”



I replaced the fuel filter (lots of bad ugly stuff came out of it) and cleared the code. The problem got better temporarily but still comes back intermittently; the check engine light didn’t come back on.



Any suggestions are greatly appreciated.



Thanks,



Tim




#2

Did you ever drive around without your gas cap on? That constitutes a large leak.

If not, did you do anything at all to check out the evap system? (The fuel filter is about the liquid gasoline & completely separate from the evap system which carries only fumes). There is probably a vacuum line stuck onto your throttle body somewhere - probably on the bottom. Start there and follow it back wards looking for broken/split lines & connections.

The sputtering could very well be from when the system purges itself. If there is a large leak it may be sending air rather than fumes into the throttle body. Or it could be from something else entirely.

If the light comes back on get the codes read and report the exact code (e.g. P1234) rather than whatever interpretation you got for it.


#3

For a few months (probably longer) I had a bunch of rust holes in my fuel filler neck which I suppose would be the same as not having a gas cap. The light didn’t come on until a few days after I brazed all of the holes shut and it ran fine for 6 weeks after that. Once it started running badly I changed the fuel filter, which was full of rust probably from the filler neck, and cleared the code. This was about a week ago.

Since then I have tried to find a vacuum leak by spraying the vacuum lines around the intake manifold with ether to no avail. I’m wondering if the fuel filter could be clogged again but I doubt that it is the root of the problem.

Its been running bad for about a week so I doubt that the light will come back on but I’ll get the code if it does.

I appreciate your help.


#4

Given the big ol’ rust holes in the filler neck don’t waste your time on the evap system unless the code returns.

Get a fuel pressure gauge on it and check it both static & under load.

With this history, maybe you’ll want to just totally clean out your whole fuel system. Drop the tank; clean the bottom & the pick-up sock on the fuel pump; change the filter again; blow out the lines; pull & inspect the injectors, etc.


#5

I just checked the fuel pressure and it holds steady at 60 psi at idle and when I rev the engine. The symptoms are getting less intermittent, happens pretty much every time I drive now. Very frustrating. Any ideas?

Thanks for your help!


#6

What engine is in it? And do you know what the pressure is actually supposed to be? I’m pretty sure that 60psi is about 2x what it should be. One thing that would cause this is a faulty fuel pressure regulator. Pull the vacuum line to the regulator and look for liquid fuel (there shouldn’t be any). Either way if it is over pressure & especially with leaking regulator you’ll be running rich…and not running all that well.

So verify the fuel pressure spec before moving on.


#7

Its a 2.5L 4 cylinder. The best I can come up with on the internet in regards to fuel pressure is 56 - 72 psi.

I pulled the vacuum line on the regulator and didn’t see any gas or any difference in fuel pressure. According to some other forums I’ve been reading the fuel pressure should spike if the vacuum line is pulled off of the regulator.

I’m going to keep looking to find the normal pressure.


#8

Autozone’s website has free online repair info. You just have to register an email address & plug in the car’s info. According to their stuff you should be at 39-40psi & it could be as low as 30 under load. (So call it 30-40psi). If you’re at 60 psi and pulled the vacuum line from the regulator w/out a change the pressure then its likely that this is the problem. (Or at least one of them). Check to make sure that the vacuum line actually has vacuum - other wise the FPR will just be inert and not take the pressure down to the right range.


#9

That’s a handy resource. When I pull the vacuum line I can hear the suction and it feels strong if I put my finger over it. Is there a better way to test the vacuum?

I checked on Autozone’s website as you recommended, the website said it should be 56-72 psi for a 1999 Ford Truck Ranger 2WD 2.5L MFI 4cyl.


#10

Right, but if you look under the fuel system part of the manual it says the regulator should bring that down to 39-40. (The 56-72 is KOEO). Did you check the pressure with engine running? If 1) the engine was running, and 2) your pressure was at 60, and 3) you pulled the vacuum line and the pressure didn’t change, and 4) there is vacuum to that line … then I would replace the regulator.

Or, given the history of the fuel system, pull the regulator off and inspect for rust - I’d not be surprised if it is all clogged up. Clean it out, reinstall and see what happens.


#11

I agree with you, the evidence is pointing to the regulator. I’ll try cleaning it out or replacing it tomorrow.

Is there a trick to separating the regulator from the return line?

Also, I was unable to find where it says the regulator brings the pressure down to 39-40 psi.

Thanks!


#12

Look under Repair Info --> Vehicle Repair Guides --> Fuel System --> Sfi system

The pressure info is under “General Information”

The regulator should more or less just pull off after you remove the screws - wiggle/wiggle. If you’re going to start by just cleaning out the old one I’d probably try to have new o-rings on hand.


#13

Cleaning it out didn’t get me anywhere. I just ordered one from ford as none of the local shops had it. Ford called it a “Fuel Pulse Damper” not a regulator but said it serves the same purpose. Apparently my truck has a returnless fuel system and there is a regulator in the tank. I hope this fixes the problem so I don’t have to drain the tank.