2000 FORD RANGER 3.0 V6 2WD AUTOMATIC. This thing is finally back in my garage for round 2 of trying to fix it. Truck starts right up, will idle till it runs out of gas. can even rev it up. If I put it in gear and drive it, as soon as I go 1-3 miles or try and accelerate excessively fast it goes into full BOG mode. engine stays running, not well, and any gas I give it trys to kill it. cant put it back into neutral and rev it up anymore, its just stuck in this shitty mode. BUT... if I shut off the engine and start it right back up, I get to run for a short while again, till the BOG comes back.

 

Welcome to the forum

Fuel pump should run full time when engine RPMs are above 400, but it should only run for 2 seconds when key is turned from off to on.

Damper wouldn't be the problem if that vacuum hose didn't have gasoline in it, vacuum hose is there for safety reasons, in case damper should leak, fuel wouldn't drip on exhaust, so not an "active" vacuum device.
If it made a difference in engine operation then that hose may have a leak.
The Damper is a rubber diaphragm that absorbs Pulse Waves from injectors opening and closing, without it the waves could increase and cause higher and lower pressure at the injectors when they open, causing more or less fuel to flow into the engine.

Computer issue:
PCM(the computer) has two main software systems, Closed Loop and Open Loop
Open loop also has Choke Mode

When you start a Cold gasoline engine it needs to be "choked" fuel injection doesn't change that.
Choke = Rich Fuel Mix, High Idle and Advanced spark timing
This used to be done with a choke plate on a carburetor, but no Jets to suck extra fuel from with fuel injection, so PCM must do it.

When you start a cold fuel injected engine do NOT touch the gas pedal
Cold Engine should start and RPMs should jump up to 1,500+, then drop to about 1,100rpm
PCM opens the IAC(idle air control) Valve all the way when you turn the key on, this causes the RPMs to go high anytime you start the engine cold or warm.

PCM has an ECT(engine coolant temp) sensor on the engine, when key is turned on PCM looks at coolant temp, this will set Open Loop condition, PCM always starts up in Open Loop, ALWAYS warm or cold.
If coolant temp is cold, under 140degF, the PCM goes to Choke Mode, if coolant is above 140degF then just Open Loop no choke.

Open Loop means PCM is using internal air/fuel mix tables based on RPM and engine size, most sensors are ignored in Open Loop, Crank sensor(RPMs), ECT and TPS are used, and MAF but only partially.
On the 3.0l engine the Cam sensor was known to be used in Open Loop in some model years, but hit and miss on what roll it might play, have read no start issue, and bogging and misfire issues related to Cam sensor even in Open Loop.

O2 sensors can only work when they are heated to above 600degF, the chemical reaction used to detect Oxygen in the exhaust needs a high temperature.
This is why all O2 sensors are "heated", to get them working ASAP

PCM monitors O2 sensor voltage and ECT temp
When O2s start to work, .1 to .9 voltage starts to change, and coolant temp is above 140degF, then PCM changes to Closed Loop.
On a warmed up engine this may only take a minute or two
On a cold engine 5 to 8 minutes.

In Closed Loop MAF and O2 sensors are the main sensors, PCM is doing "on the fly" air/fuel mix calculations based on in coming air WEIGHT and Oxygen levels in the exhaust.


So when you have a engine issue first see if it is happening in Open Loop and Closed Loop or just during one of these.
Your issue seems to be related to Open or Closed Loop but can't tell from your post, but the good running and then poor running after a few minutes points to that


You can buy an OBD2 Bluetooth Reader, under $50
These connect wirelessly with smartphone or tablet as the display
They work on ANY vehicle sold in the US/Canada since 1996, its the Law, so not a Ford thing, or even made in North America thing

With an OBD2 reader you can view Live Data like coolant temp or MAF air flow, to see if PCM is getting the correct info to run the engine correctly.

Computer programmers mantra: "Garbage in = garbage out"

Yes, PCMs can fail, no way to test them, but you can see if they are getting the correct input so should have the correct output

PCM Codes are not in "english", they are in computerese, binary, not to be used unless you understand what they really mean.
i.e. Lean code does NOT mean engine is or was running Lean, that's the "english" translation, in binary it means the PCM is opening the injectors longer than it calculated for the air flow data used, and the O2 voltage received.


Not a big deal but try to break up your posts into paragraphs, one long paragraph makes it hard to read

 

Thanks RonD,
I really appreciate the quick response, and sorry about the GIANT paragraph. I have a bad habbit of doing that. :)

 

UP DATE TIME!!!
I tore every sensor on the engine off. checked wires, grounds, connectors/connections, cleaned everything up and put it back togeather.

Swapped the fuel filter out, it was mighty dirty... tank port not covered for a couple months... still havent put the bed back on yet.

Cleared the codes and started a test cycle:
Now Im pretty positive im going in to limp mode due to a transmission failure.
I got it to operating temperature, ran around the block. Hit 35mph, Fell flat on its face. Started it back up, ran down the road, hit 35 back on its face.
Threw a CEL. Transmission codes, wrote em down, went back for a second test.
Hit 35, down again.

At this point I'm getting excited!!! still messed up but FINALLY consistant results.
This time I wanted to ease up and see if I could creep past 35. Listen to the transmission shift as I SLOWLY get to 35... Dies as it tries to shift.

Eureka, those random tranny codes might have been my real issue all along. or at least a part of the issue/ the main one. Today im gonna check the transmission out and try and get some clue as to what is going on down there. cant get live data yet or a better code scan till I get my hands on a new scan tool.

If your curious about my codes I'll post em this afternoon. My scan tool was old and took a dump, been lazy and using a friends instead of getting a new one, now im using my grandfathers... its cheep and only reads active CEL codes. and just gives the code #. I'm buying a new one this week....

 

Fuel injection computers have REV Limiters, these are engaged when in Park or Neutral on vehicles with automatics
Park and Neutral are detected by the DTR(digital transmission range) sensor on the drivers side of transmission, on the shift linkage.
The DTR also does Reverse Lights and passes starter motor activation, so no start "in gear"

If the DTR is always "telling" computer you are in Park or Neutral then you would have REV Limiter on-line when driving

Engine off
Put trans in Reverse to see if Backup Lights are on
Also put trans in Drive and try to start engine, FOOT ON THE BRAKE!!!!
Engine should NOT crank, if DTR is working
Starter motor should only work in Park or Neutral

This doesn't mean computer is getting the "in gear" signal so no REV Limiter, it is just a test

 

Even more goofy stuff now,

I got my hands on a kinda shitty scan tool, but one that can do live data, so I decided to see whats going on.
I'm still getting no DTC's :( but while monitoring the live data it shows

FUEL SYS#1 CL-FAULT on occasion then it will just go CL
FUEL SYS#2 N/A
CALC LOAD sitting right around 33.3% with rpm held at 2500 Load drops to 18%
ECT 207*F
STFT B1 -2.3% -- 0.0%
LTFT B1 .8% -- 5.5%
STFT B2 -10.2% -- -8.6%
LTFT B2 -10.9% -- 9.4%
ENG RPM @ IDOL 888 -- 921
SPARK ADV. 12 -- 16.5
IAT 93* -- 100*F
MAF .63 -- .67 LB/MIN
TPS 11%
O2S B1S1 .160V -- .695V
STFT B1S2 -5.5% -- -2.3%
O2S B1S2 .125V -- .685V
STFT B1S2 99.2%
O2S B2S1 .090V -- .700V
STFT B2S1 -10.9% -- -8.6%

 

IAT - Intake Air Temperature... is it really that warm there now in Arizona? I'm jealous.

 

Yes, nice and warm where you are from that IAT temp

Bank 2, Drivers side Fuel Trims are RICH
STFT B2 -10.2% -- -8.6%
LTFT B2 -10.9% -- 9.4%

Thats Minus 10 right?
If so it means computer is adding LESS fuel than it has calculated as correct, 10% less
Could mean a leaking injector
Could also mean O2 sensor issue, but they usually fail LEAN, so high + fuel trims, i.e. 10-15%, no -

MAF sensor looks fine for 900rpm idle
Should go up to about 7lb/min at 2,500rpm

 

New Data:
@ 2,500 rpm MAF only getting 2lb/min

The limp mode is only activating when the vehicle is at operation temp. Ran it around the block to warm it up. Ran like a champ. Got up to 70mph. But when it warmed up, flat on its face.

The limp mode is starving it for fuel and killing the voltage for the O2 sensors. When under load. In park at idle stats look fine. Press on the gas and down she goes.

CALC LOAD 100%
O2S B1S1 00.000V
STFT B1 48%
O2S B2S1 00.000V
STFT B2 48%

 

+48% ?? engine is being flooded not starved

O2 sensors generate their own voltage, .1 to .9 volts
.1 volts is too much oxygen in the exhaust, Lean
.9 volts is too little oxygen in exhaust, Rich

.0 volts means O2s are not connected and Lean

When O2 sensor voltage is low, Lean, computer starts to open fuel injectors longer
Say computer calculated injectors were to be open 100ms(milliseconds)
If computer saw lean from O2 then it would open injectors for 102ms(2%), then 104ms(4%) then 106ms(6%), ect............
Until O2 sensors showed .4volt, balanced oxygen levels in exhaust
Yours are going up to 48%
-48% would less fuel

O2 sensors are Heated, they have 4 wires, 12v and Ground for the heater, and 2 wires for the sensor, one is a common reference ground to computer(shared by many other sensor), the other is the .1-.9 volt to computer.

So you problem is this, the wiring on the O2s, or the computer it self, I can't see BOTH O2s failing like that.

When cold the computer ignores O2 sensors, they can't start working until they are above 600degF, which is why they are heated.
And this is why it runs OK cold

I would unplug the O2 sensors and see how things go, but wires might be shorted so unplugging won't help

 

Finally Fixed.

Defective MAF.

I diagnosed it the wrong way but... It's running great and it's out of my garage.

I decided to run live data on my 07 and compare stats. The MAF on it, under heavy load, pulls 20-40 LB/MIN. The 2000 wasn't getting over 4. Got it to 11 once but still lower.

So thinking... a ranger is a ranger. Went and bought a new one. Ran like **** at first. Like hardly started and barely moved at all. And still low LB/MIN. BUT... Once the computer got readjusted. Ran like a champ. Nothing stopping it now.

still a huge difference in LB/MIN stats but apparently an 07 sport is supposed to pull in Way more air than a 2000.

Thanks RonD you helped me understand how this beast thinks way more than I knew before.

 

Good work

Thanks for the update and fix


A 3 liter engine can only pull in 3 LITERS of air at wide open throttle every 2 RPMs(one complete cycle of engine)

So unless the other 3 liter engine is turbo or super charged the MAF air flow should be the same at the same RPM/throttle position
If one engine had partially clogged exhaust it would show less air flow at higher RPMs, because "used" air can't get out so "new" air can't get in

A 4 liter engine, or 5 liter engine, would of course pull in more air every 2 RPM which is why they would have more power than a 3 liter engine
Air = power on engines, which is why, and how, turbo or super chargers work to add power, they force more air into an engine, it's as simple and as complicated as that

If I remember correctly a liter of air at sea level and 70degF weighs about 1.3grams, but is has been awhile since I needed that info, lol.