Greetings all... MAF sensor appetite

Craiger · Jul 1, 2018

My first posting here failed and I lost the message
Anyways, I'm an old guy with a lot of experience in automotive/truck repair.
Started in 1968 or so, and repaired mostly imports and was the go to guy on the then new Bosch MPC fuel injection system.
I put away my wrenches in 1993, professionally at least.
I have a 2002 4.0l XLT purchased in the summer of 2003, it now has just a bit over 70k miles. :icon_thumby:

The black beauty had the winter off this year, just too many projects to tend to and having the brake line rupture (the longest one) I thought it best to wait until i had time to properly attend to it. I had disconnected the battery and put it on a battery tender charger thing. Having had disconnected the battery... not a good idea in hindsight.
Last week I went to start the mighty 4.0 and it just cranked over with only a hint of fire in the cylinders. Now the last time my Ford did this it was at a rest area somewhere in Indiana and the time before that at a drug store after picking up some items. Both times it was the MAF mass airflow sensor. Sadly I have no codes to read.
Has anyone heard of these MAF failing in such a fashion? I installed a new one without much thought to testing anything and the result is a no fire up, just cranks away. The MAF was last repaired a year ago April and only has about 1500 miles on it.
I am thinking something else other than the MAF sensor.
Anyone having dealt with this issue?

Denisefwd93 · Jul 1, 2018

Welcome aboard I'm an old gal, I'll be 70 this month most of my whole life was in the HVAC business in it around it and ultimately owning the family business. Wooden Boats and Wooden Boat restoration antiques and house restoration are my strong points, auto mechanics I'm learning as I go!

Many of the people on this forum are really sharp!

I'm on my second Ranger both have 4.0 engines and one of the first things I learned how to do was clean the MAF, I don't think that is the reason she's not firing up. Most likely you'll need to check Spark & fuel.

Craiger · Jul 4, 2018

Thanks for the reply Denisefwd93.
This one really has me stumped. the 4.0 will fire and run on starting fluid (ether) and I get a dribble of fuel out of the test port on the fuel rail. The pump on this truck was never very loud. in the past, the mass airflow sensor was the culprit, that one was replaced a year ago April 2017.
It very well may be the fuel pump, jumping the relay for it does nothing. I still need to try jumping out the roll over switch
HAPPY Fourth of July

Denisefwd93 · Jul 4, 2018

I don't think you need a ASE certification to know it's a fuel pump lol

RonD · Jul 4, 2018

Welcome to TRS

Fuel pump only runs for 2 seconds each time key is turned on, but it runs for 2 seconds EACH TIME key is turned from off to on

So cycle key off and on as many times as you see fit and listen for the fuel pump, or check test port on engine.

In 2002 model Ranger you would get a "Check inertia switch" light on the dash if there was no12v fuel pump power, or Check Engine Light(CEL)
Computer monitors the 12volts it sends to fuel pump, even for that 2 seconds, so you would get a warning light on dash if fuel pump power was the issue.

Computer does not have a fuel pressure sensor, so if fuel pump failed there wouldn't be a warning light............just a no start

And no, the MAF sensors don't fail that often, they should be cleaned every 2 years or so but shouldn't cause a no start just bogging or Lean Codes when failing or dirty.
Your Computer already knows it is running a 4 Liter engine, so it knows how much air will be sucked in at any given RPM and throttle position, its just math, and that all this computer was built for, on the fly calculations.
MAF is there to "weigh" the in coming air, sea level and 4,000ft elevation air is a different weight, colder air is heavier than warmer air, i.e. "hot air rises"
Gasoline's 14.7:1 air:fuel ratio is a weight ratio, 14.7 pounds of air to 1 pound of gasoline
So the weight of the air is important for best running and fuel economy.

There are some engine computers that won't allow starting with MAF sensor unplugged, but most do start and run, it's the software inside, because the engine can run based on air:fuel mix tables in memory without MAF sensor input, it just may not run well if you are not at sea level with moderate temperatures, lol.

Craiger · Jul 4, 2018

Hey, thanks RonD.
Is there a sure fire way to run this pump with out jumping it near the tank location? I tried at the relay but that didn't do anything. I swear I can not hear the pump, even with the gas cap removed and a helper cycling the ignition switch on & off
Thanks

RonD · Jul 4, 2018

Then pump is dead, it isn't that quiet
You can tap on the bottom of the tank and see if pump starts working again, rubber mallet or wood, not steel hammer.
Electric motors will continue to run once started, its the getting them started is when you notice the failure

Best way to change fuel pump is to pull the bed back or off

There are six T55 torx bolts in the bed, and 3 Phillips screws at the gas cap filler tube that need to be removed.
And then unplug the tail light wiring

Some put back in the two rear bolts in the bed, but not tight, then tilt the bed up and prop it up using ???, 2x4s..........up to you really

Lots of videos out there on changing Ranger fuel pumps

Dropping the tank is also an option, but very hard disconnecting hoses and wiring to get it down.
And then VERY hard to get it back in and lined up to bolt in the straps
If you have a shop with a lift and transmission jack then this would be best way, but with truck just jacked up it is a real pain.

As far as replacement brand, I would spend the money for Motorcraft, only because fuel pump is a pain to change.
Less expensive brands often come with 2 year or even lifetime warranties, hold on to the receipt, it often takes 2 or 3 of these to get one that lasts, past the 2 year warranty.

If your gas gauge works fine then you may be able to just replace the pump not the whole assembly, which saves a few dollars

My take on using 3rd party parts vs Ford/Motorcraft is basically how hard is the part to change and what happens if the 3rd party part fails.
Most stuff is not too hard to change and wouldn't leave me stranded anywhere if it broke
Fuel pump isn't one of those parts, lol.

Craiger · Jul 5, 2018

Hmmm my post vanished?
Thank you RonD
I'll get to the thump the pump test today, I have a 1x2" stick that will reach the threaded ring I'll give that a few judicial taps to see f I cant wake the motor up.
I am not looking forward to dealing with the T-55 torx bolts... I have a factory liner and a fiberglass cover to deal with. I thought of exposing the 6 T-55's with a 2" holes cut into the liner but I just cant bring myself to doing that.

Craiger · Jul 5, 2018

Oh, by the by have a great birthday, I turned 68 this past june

Denisefwd93 · Jul 5, 2018

You talking about a half hours work if a Friend helps you lift the cap off. Maybe an hour or two tilt the bed up,

But you can always take it to a shop and have it done! It's what I used to do, it's almost always six or seven hundred dollars, that should motivate you to do yourself. Lol

Craiger said:
Hmmm my post vanished?
Thank you RonD
I'll get to the thump the pump test today, I have a 1x2" stick that will reach the threaded ring I'll give that a few judicial taps to see f I cant wake the motor up.
I am not looking forward to dealing with the T-55 torx bolts... I have a factory liner and a fiberglass cover to deal with. I thought of exposing the 6 T-55's with a 2" holes cut into the liner but I just cant bring myself to doing that.

Craiger · Jul 11, 2018

Ta Daa New pump is in

Denisefwd93 said:
You talking about a half hours work if a Friend helps you lift the cap off. Maybe an hour or two tilt the bed up,

But you can always take it to a shop and have it done! It's what I used to do, it's almost always six or seven hundred dollars, that should motivate you to do yourself. Lol

Thanks you guys for the heads up and direction/encouragement.
I wound up pulling out the four bed bolts and loosening the rears enough to tilt the bed up in order to access the fuel pump. Actually I broke the front right bed bolt. The pump install is/was pretty much a no brainer, I used a 1X2" pine board to turn the retaining ring.
The bed hardware: I went over to my local hardware store and found stainless steel 3/8th" hardware, it may not be as strong as the original, but it can pass right through the old speed clip nuts originally installed by FoMoCo. So I am only replacing the front bed bolts. It is pretty rusted out in that area, no doubt due to the factory bed liner and Wisconsin winters.
The two bolts, large washer, small washer, lock washer and nut everything stainless steel. the two sets of hardware set me back $9.25.
The bolts were an absolute nightmare to turn... impact wrench? Forget about it!! I used a 20" cheater bar/pipe over my Snap-on 1/2" ratchet, driving that T-55 Torx bit. Guess I found out I am not really up to this sort of thing anymore BUT I got it done. The bed sure could use some repair but I think a wide strip of steel bolted in via the two bolts would go a long way in securing that part of the bed than just washers.
The heat shield needs a few self tappers as well.
Now the next feat, replacing the long brake line that runs along the frame. What fun :annoyed:

RonD · Jul 11, 2018

Good work

Thanks for the update and how-to

Just add a new brake line inside the frame rail, no need to pull the old one out, you can feed a new line in.

Denisefwd93 · Jul 12, 2018

Good job but without pictures we don't know it really happened lol.

Just like most things thinking about it, makes it more difficult than actually doing it, you won't believe how much I've done to the truck I just got and I'll be 70 this month.
Transmission swap.
Fan clutch and fan.
Front brake hoses
Front calipers rotors brakes bearings
Air conditioner evaporator
Air conditioner condenser,
Air conditioner hoses,
IAC
TPS

Craiger · Jul 12, 2018

It CAN be done and it was

Denisefwd93 said:
Good job but without pictures we don't know it really happened lol.

Just like most things thinking about it, makes it more difficult than actually doing it, you won't believe how much I've done to the truck I just got and I'll be 70 this month.
Transmission swap.
Fan clutch and fan.
Front brake hoses
Front calipers rotors brakes bearings
Air conditioner evaporator
Air conditioner condenser,
Air conditioner hoses,
IAC
TPS

Pictures? I have a few
I would really like to repair this rotted front section before I bolt it back down
I almost feel like cutting it off and putting a wooden rail under that front support rail. Sounds like a travisty, but it would give more options to getting the bed tightened down. :dunno:

Poor Ranger never asked for this :sad:

Denisefwd93 · Jul 12, 2018

You wouldn't be the first one to use some wood under there, white oak would be the choice it lasts almost as long as Steel maybe even longer.

Bed bolts Dorman, not cheap

https://www.amazon.com/Dorman-924-310-Bed-Mounting-Hardware/dp/B00CS335VS/ref=mp_s_a_1_2?ie=UTF8&qid=1531435282&sr=8-2&pi=AC_SX236_SY340_FMwebp_QL65&keywords=ford+ranger+bed+bolts&dpPl=1&dpID=51Oebow0qFL&ref=plSrch

Greetings all... MAF sensor appetite

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