2005 Ford Ranger Won't Go Over 55 MPH

[emanheeman]

I have a 2005 Ford Ranger Level 2 4X4 with a 4.0 Manual. It will not go over 55 MPH in 3rd, 4th or 5th gear. Once I get up to 55 the tach and speedo begin jumping down and the check engine light flashes. Seems like the car is being governed to 55 MPH. Has anyone else experienced this? Recommendations on how to correct it? Could it have anything to do with the CMP sensor?

Here's a video of it happening in third gear: https://drive.google.com/file/d/1lGeX_VUEZ6FfsdkvZMvpLeFgY5A2OZrQ/view?usp=sharing

 

[RonD]

Welcome to TRS

Well there is a 3,000rpm REV limiter that is only used when Speedo shows 0MPH or clutch pedal is held down(manual)
There is a speed limiter as well but 95MPH was most common

The video looks more like an engine issue, fuel system maybe, if it does it at different RPMs in different gears but 55mph seems to be the constant then fuel would be the most likely
Dirty fuel filter ???
Weak fuel pump ???
2005 expected fuel pressure at engine is 55psi

It takes a certain amount of fuel(HP) to maintain 55MPH in any gear, so if fuel flow is limited then thats how it would present, MPH specific not RPM specific

And sounds like there is an exhaust leak, shouldn't effect system in a way that would cause current symptom

Would also be curious about the CODES that are being set
Flashing CEL is "misfires are occurring BACK OFF throttle"
If its a fuel system issues would expect Lean codes
And could be Knock sensor cutting back if pinging is being detected from lean mix

 

[55trucker]

Sounds as tho you have a case of the *Sammy Hagar* virus,

did you do anything to the engine controls before this happened?

 

[emanheeman]

Welcome to TRS

Well there is a 3,000rpm REV limiter that is only used when Speedo shows 0MPH or clutch pedal is held down(manual)
There is a speed limiter as well but 95MPH was most common

The video looks more like an engine issue, fuel system maybe, if it does it at different RPMs in different gears but 55mph seems to be the constant then fuel would be the most likely
Dirty fuel filter ???
Weak fuel pump ???
2005 expected fuel pressure at engine is 55psi

It takes a certain amount of fuel(HP) to maintain 55MPH in any gear, so if fuel flow is limited then thats how it would present, MPH specific not RPM specific

And sounds like there is an exhaust leak, shouldn't effect system in a way that would cause current symptom

Would also be curious about the CODES that are being set
Flashing CEL is "misfires are occurring BACK OFF throttle"
If its a fuel system issues would expect Lean codes
And could be Knock sensor cutting back if pinging is being detected from lean mix

I hadn't even thought about the fuel system. I changed out the fuel filter about a month ago with Duralast (Autozone) brand fuel filter. I can look into checking the fuel pressure. Do you have any recommendations on how to check the pressure?

That rattle that can be heard in the video is from the shifter knob. Its really loose and rattling.

 

[emanheeman]

Sounds as tho you have a case of the *Sammy Hagar* virus,

did you do anything to the engine controls before this happened?

After buying the car in May, I swapped out the ignition coil, wires, spark plugs, fuel filter and did an oil change. Not sure if the previous owner had done something and I didn't test drive on the highway/at high speeds before buying it. The truck is very high mileage around 230,XXX

 

[RonD]

Spend the $10-$15 on an ELM327 OBD2 bluetooth reader, these work on any vehicle sold in the US or Canada since 1996, so not a Ford or even Ranger thing
And they work with any bluetooth phone or tablet/laptop
APP is free or $5 for more advanced info

You can of course get codes and clear them, but you can also watch Live Data while engine is running
You could watch if fuel trims are getting high as speed increases which would mean fuel flow is decreasing under load

Very handy tool to have if you plan on having or driving any vehicles


2005 Ranger may or may not have a fuel pressure test port, they were hit and miss starting in 2001 on the 4.0l SOHC engines
It will be on the fuel rail and looks like a tires air valve, because that is what it is, a schrader valve, usually on the passenger side of engine

 

[Dirtman]

The video looks exactly like what happens when the engine would hit the rev limiter sitting in neutral or hitting the speed limiter on the highway but there's no logical reason it would be at the same RPM at 55mph in different gears so that's a head scratcher for me...

Could the VSS be giving good info to the speedo but bad info to the ECM? I.e somehow the ECM thinks your doing 100 but the speedo is still correct?

 

[RonD]

Well in 2005 Ranger the computer is the source for speedo, 2001 - 2011 OSS sensor goes to computer then out to speedo/odo

But certainly possible to have internal computer fault

 

[Dirtman]

I dunno, just saying anytime I've seen exhaust restrictions or fuel restrictions that cause power loss, they don't happen so abruptly and at consistent speeds.

 

[RonD]

Exhaust restriction would be more RPM based, like a dirty air filter would be more rpm based

Any engine needs a certain amount of horse power to get to and maintain a certain speed, based on vehicle
And that's a function of the weight of fuel added to the engine, the energy released
An engine can be more efficient at a certain speed and rpm but the fuel weight needed doesn't change all that much to maintain that speed

 

[Dirtman]

Exhaust restriction would be more RPM based, like a dirty air filter would be more rpm based

Any engine needs a certain amount of horse power to get to and maintain a certain speed, based on vehicle
And that's a function of the weight of fuel added to the engine, the energy released
An engine can be more efficient at a certain speed and rpm but the fuel weight needed doesn't change all that much to maintain that speed

Exactly. Happening constantly at 3,200 rpm makes more sense than happening at 55mph. He says it happens at 55mph in 3rd, 4th, and 5th which would all be wildly different RPMs. This is a speed related issue not RPM based on his description?

The engine doesn't care what the "MPH" is, it has no way to tell. Only the computer does...

55mph in 5th takes 2,800rpm or x amount of fuel, 55mph in 3rd takes 5,800rpm and x amount of fuel. Totally different fuel use and RPM. So why would it cut out at 55mph in both gears if it's a fuel issue?

 

[55trucker]

If this were a fleet owned diesel tractor I'd say that a Tach-o-graph had been installed.

I didn't get to view the video clip, it did not buffer.

 

[rubydist]

I would start by putting in a new OSS, because if the OSS is bad and sending out double pulses that would pretty much be where you are hitting the governor. And, it also could be the input section of the pcm is bad and reading double the pulses that are really being sent.

 

[emanheeman]

Update: alright so I caved and dropped it at the dealership last Friday July 16th. It was a strange problem they hadn't seen before and i finally got a call today that they think they've figured it out. They think its the front wheel ABS speed sensors. Over the phone I was told that they connected a code reader to it, drove it and thats the code it was pushing out. They told me it would cost $900 to replace them. That was hard no from me because I bought the car for $2,000. Going to go pick up the car tomorrow and talk to the representative that I dropped the car off with a little bit more about how they came to that conclusion. Weirdly during the call I was told that to replace the sensor they were going to have to cut wires and re solder. Looking up the sensor and checking my workshop manual for the car, its all plug ins and clips so I wonder if a wire between the sensor and wiring harness is exposed or broken

 

[Dirtman]

Lost me on this one. I can't see how a wheel sensor on a 2005 can effect the the vehicles speed. The wheel sensors don't provide speed information to the ECU. The wheel sensor just pulses to determine if one wheel is going slower than the other indicating a skid to activate the ABS.

They all collaborate with the VSS which is the only thing the computer cares about relative to the vehicles speed.

On new models those sensors can activate stability control and slow the vehicle, but we are talking about 2019 rangers, not 2005. In 2005 they just weren't that sophisticated. So I'm curious what the dealer says when you pick it up. Get lots of details...