2005 Ford Ranger Won't Go Over 55 MPH

[emanheeman]

The VSS and rear WSS are the same thing. Computer uses the signal from the VSS mounted on the differential for both speedometer and rear ABS function.

I believe this not the case because my speedometer still worked fine with the rear WSS on the rear differential unplugged. I think there is a VSS on the transmission but am searching my workshop manual to confirm

Update/Edit: I attached a picture of the VSS on the transmission

 

[Dirtman]

As far as I knew 98-2011 used a single sensor for the VSS and ABS?

Of course I've only dealt with autos so maybe the manual trans still uses a sensor on the trans? Doesn't make much sense for them to do that but who knows.

 

[RonD]

Its a 4WD

In 2001 Ford switch to from VSS to OSS speed sensors located on transmission, on 4WDs the speed sensor WAS located on the transfer case for correct speed in 4LOW
So with OSS on the transmission the Computer must correct for speed when in 4LOW
If computer "thinks" you are in 4LOW all the time................well 55mph would be way to fast, lol

Shift into 4low see if computer corrects for speed
Then shift back into 2WD


You are kind of at a place were the Computer might be the issue
2005 Rangers were unique in that Ford skipped 2005 models for PATS(passive anti-theft) but the computers were still "married" to the instrument clusters(HEC)
But I think you can "remarry" them using Forscan, an inexpensive Ford diagnostic tool

 

[emanheeman]

A little scared to play around with switching the car into 4WD because the transfer case has no oil in it. (It has a very fast leak. It'll drains in about a week. Another problem that needs to be fixed.)

 

[RonD]

Then just switch to 4high and then 4low, see if it works, then shift back to 2WD, may need to move forward or backward a bit, but for sure won't hurt anything to do that with low fluid

You shouldn't be driving it at all with no fluid in transfer case, just FYI, fluid is needed in 2WD same as 4WD
The chain drive is always spinning in 2001 and up Ranger 4x4s, as the front hubs are always locked

 

[emanheeman]

Just drove the truck with the VSS on the transmission unplugged, took it for a test drive and had the same issue. Then I tried switching into 4 high, rolled it backward and then forward and then tried 4 low, backward and forward, went on a test drive on the high way, no change.

 

[RonD]

With OSS on transmission unplugged the speedometer was not working correct?

And the CEL came on?

 

[emanheeman]

With OSS on transmission unplugged the speedometer was not working correct?

And the CEL came on?

Yes, the check engine light was on and throwing a code

 

[RonD]

And computer still limited fuel/spark at about same speed, or was it less?

I would think it should be sooner as REV limiter would kick in at 3,000rpm with no speed signal

 

[emanheeman]

The speed sensor wasn't plugged in so I am not sure what speed it was at exactly but it felt about the same 55 MPH. There was no rev limiter with the speedo disconnected. I reved over 3,000 RPM in the lower gears and didn't have any issues. I also just went out to the car and was able to rev the engine up to 4500 RPMs while parked. I didn't want to go past that with no load on the engine

 

[fastpakr]

Just for fun, have you tried hooking up a fuel pressure gauge and running it to somewhere visible while driving?

 

[RonD]

............................. I also just went out to the car and was able to rev the engine up to 4500 RPMs while parked. I didn't want to go past that with no load on the engine

Try it with clutch pedal down(thats the neutral signal)
Very odd it will REV past 3,000 at 0MPH in gear(clutch pedal up) though

 

[Dirtman]

I'm still on the theory that the computer is getting bad info either because the ECM is fubar or the VSS is fubar.

 

[emanheeman]

I'm still on the theory that the computer is getting bad info either because the ECM is fubar or the VSS is fubar.

Is there anyway I could test that theory?

 

[Dirtman]

Is there anyway I could test that theory?

Have you thrown a new VSS on it yet? They aren't expensive and I'd be inclined to replace it on suspicion alone.