Fuel Sensor...Fuel Pump...????

vang0017 · #1 07-14-2009, 07:12 PM

Recently, my 1996 Ford Ranger 4.0 V6 4 wheel drive...have been dying in and out. Sometime it works and drive for a bit, if i stop and turn off the engine ...then it will not turn back on... it cranks...but no starting completely... I check and it seem like there is no fuel coming...so i though it was the fuel pump but...SOME MECHANIC TOLD ME THAT... is the fuel sensor???

My question is... are there such things as fuel sensor for these kind of car...cause i never heard of it before... If it does have it...where would it be located at? And if the sensor is bad...would it cause these kind of problems... ??? please help... i don't want to spend 500$ for nothing. Thanx

STL · #2 07-14-2009, 07:27 PM

check engine light come on?

vang0017 · #3 07-15-2009, 07:11 AM

Quote:

Originally Posted by STL

check engine light come on?

NOPE... no check engine lights at all...

Grrranger · #4 07-15-2009, 08:53 AM

You need to have good fuel pressure to start with, which should run to a regulator before going to the fuel rail for use by the injectors. The way it sounds I would definitely suspect a fuel pump. A fuel pressure sensor may be present but it's purpose is to fine tune injector calibration through the ECM module.

wilson · #5 06-22-2010, 06:31 AM

My fuel problem is becoming more prevalent even after adding lots of Sta-bil so I am beginning to believe as some of you have suggested there is a physical problem in the fuel system.
The engine ALWAYS starts fine. I have never had a starting problem; and none at very low speeds; but when I need more fuel to go uphill or when towing a load; then the sputtering begins.
The pattern seems to indicate not enough fuel to the injector and may even be an injector problem. More testing and research is necessary.

dworth24 · #6 06-26-2010, 09:37 PM

i'm having same problem with my 04 ranger. my bro is a mechanic and he is stumped by this. codes i am getting say cam sensor is bad. waiting for part to come in. its a process of elimination thing

wilson · #7 07-14-2010, 07:44 AM

Misfiring this past week was severe enough to turn the "check engine" light on so I drove to the AutoZone where the analyzer determined fifth cylinder misfire. This was encouraging since i have replaced plugs, wires and coil pack within the last few thousand miles. I am now thinking there is an electrical wiring problem which I will search out.
Meanwhile; I still had the carbon emissions on the right tail pipe extension as proof of excessive oil consumption so I decided a third container of White Shephard was in order; and since adding that to the crankcase a week ago and cleaning the tail pipe there has been no further carbon build-up; so I feel good about stopping the oil consumption.
There may be a problem with the way I hooked up the tachometer when I bought the truck in 1998; but for the past 11 years it has run well most of the time. The misfiring has only been an issue over the past few months. This I will also re-visit to search for alternative connections.

Cdiz · #8 08-31-2011, 08:24 PM

i had this problem in my ford escort way back when. the problem was bad spark plugs. it would run fine when i wasnt hammerin on it but tryin to get it going is when it like sputtered out

-cdiz

FireRanger · #9 08-31-2011, 08:29 PM

"Fuel sensor"??? Time for a new mechanic. The only fuel sensor is the one for the gauge the engine does not care what that reads. I'm not sure how or even if the engine actually monitors fuel pressure, but I've never heard of such a sensor or sensor problem. And the computer does not show any fuel pressure reading when connected to laptop or scangauege.

In other words.... fuel pump.

Midwest Dually · #10 09-02-2011, 10:36 PM

I recently learned that when it comes to the fuel delivery of these trucks, that instead of the fuel pump being turned off and one via (+), it is grounded by the computer to run the pump.

To further make things more complicated and pointless.. It is not just an (on/off) fuel pump, but one that has an operating range. As the computer detects the need for more fuel, it operates the fuel pressure regulator, as cranks the fuel pump to the needed PSI. So at idle, not much fuel is needed, the computer tells the pump this. As the need increases by acceleration, the fuel pump is turned up higher to match the need. Again, its done through grounding the fuel pump.

I am battling the same issue. I replaced the Fuel Pump, Fuel Pump Relay, Fuel Pressure Regulator, MAF Sensor, Vacuum lines, IAC Valve, Inertia Switch. When I went to get the codes pulled, the ECU/PCM would not communicate with the code scanner. I had to conduct a PIN test at home with a jumper wire. I finally pulled a code even though the "Check Engine Light" was not on...

Code: 542= Fuel Pump Circuit Open, PCM to motor.

Not being given the most clear answer other then being told to keep testing things I have already tested, its becoming apparent it may be the Computer that has failed.

To make it really strange, I am only having this problem when the outside temperature is above 90 degrees. This may also be why the computer fails. There is a defect in it that once the ambient temperature exceeds 90 degrees, the computer has the issue from being too hot....

Should have this problem solved in a week as I am going on a ECU/PCM hunt, and have to duplicate the scenerio to get the result. If it works, it may be something to check into. if it doesnt, I am stripping the entire fuel system and running an aftermarket system.

FireRanger · #11 09-03-2011, 05:02 AM

The data port has a fuse that is probably blown if it isn't working. Also, the computer using PWM to control the fuel pump is neither complicated or pointless. It is quite common and necessary.

I'd trace out the PCM to Fuel Pump wire before replacing the computer. Your theory on temperature is pretty good but its just more likely that something else is wrong. PCM's rarely fail.

Midwest Dually · #12 09-03-2011, 08:59 AM

I tested the circuit from the pump to the PCM, including the distro box recently.. And just to make sure, I will retest again today.

My only stand on it all, is that I am not a fan of designs that get overly complex for reasons that are not clear.. Later on down the road, someone, some where, will be working on the dang things! LOL! My biggest concern is why the problem persists only when the outside ambient temp exceeds 90 degrees???? I have had this thing break down on me every single time and the temperature seems to be the only factor that is present during the breakdown.

FireRanger · #13 09-03-2011, 10:03 AM

There is nothing overly complex about it and the reason is perfectly legitimate. You not knowing about it does not make it pointless or wrong. The PCM modulating the fuel pump is nothing new. Those who need to work on them are usually well aware of it.

If you're sure there is nothing wrong between the PCM and the pump, and the pump is new, then I guess that leaves only the PCM.

Midwest Dually · #14 09-03-2011, 09:48 PM

The fact that still in most all of the diesel systems, the fuel pump runs a constant pressure that does not fluctuate, this also goes for many other types of gas run vehicles, would naturally be a surprising issue to someone when encountered with a "variable" fuel pump, not an "on/off" pump, similar even in high performance applications.

My point is coming from the aspect I am admitting that I am not understanding why the pump is a variable pump that will increase fuel pressure and decrease fuel pressure and the necessity behind it, when there is a fuel pressure regulator. The injectors themselves can only max out to a specified amount of fuel and at a preset amount of pressure. Why the fuel pump needs to vary in pressure as the throttle increases, negates the point behind a fuel pressure regulator. In a sense, its redundant. I am sure somewhere someone thought this was a good idea, and got it cleared to be part of this vehicles operating system, to later on down the road have a TSB put out about it, and in who knows, like other recalls, get put on that list too! LOL!

I am hoping its the computer!

FireRanger · #15 09-03-2011, 10:23 PM

In the 12 years I've owned a ranger and been on ranger forums, your the first person to have this problem. So apparently it isn't as troublesome as you would like it to be.