Just drove home from florida today. I will check that tommorow. Mine isnt as bad as The guy in california. I can run up to about 83 or 84 without hit rev limiter. Not a real problem in tenn. but some of those interstates in Fla. You have to run in rh lane to stay out of the way. By the way gas ranged from 292.9 to 309.9 cheapest good gas was in ALa. at 279.9 for bp. regular.

 

Wow, around here prices jumped 10 cents last night, and then dropped 5 tonight...

 

I bought the PSOM from a speciality company in Detroit. There are two programmable things for the PSOM: The odometer reading and the tire size. There is a chart that equates tire size to a code in the PSOM and that plus the odo mileage were programmed into the PSOM before it was sent back to me. The speciality company had me do the sweep sequence to pull out the code from my speedo so it could be programmed into the new one. Basically with replacing the PSOM nothing changed as to fixing the problem.

The VSS was replaced, all the wiring was checked, the MASE mechanic says he was able to monitor the signal coming from the VSS and it was steady. He gave up.
Ford tech support was useless and did not even know this thing had a speed limiter.
They call the cut out at 75 a rev limiter. But, I can go 74 and put it in 3rd and with a 4:10 gear, really push up the RPMs and nothing happened as to the cutting out. So, it is really a speed sensor limiting device as to my thinking.

I have heard several listers question the 4:10 gear. What ever gear that was in this van when I bought it was so tall that overdrive was useless. This van is a high top conversion loaded to the max. I sure like having the TV and VCRplayer with headphones in it as the kids watch that screen and leave me to my senses.

Even with the 4:10, it luggs in overdrive going up a hill or bridge. I do hear what sounds like spark knock being checked but the computer shows no codes as per the mechanic.

I have had a lot of work done on the van. It has 155K on the clock and does not burn oil and has good oil pressure. Just put 500 miles in three days of vacationing and no problems except the speedo deal here.

This 94 was the last year for the I computer which has liimited data. Sure wish it was the II computer which has more data.

Tom Taylor
94 f150 van

 

There is the problem, the company used your OLD conversion constant for the swap. This is causing the transmission to shift wrong causing the lack of power. Please double check the code, as it sounds like they didn't put the right one in.

 

The exciter ring did not change and the VSS takes its reading from that. I did not change tire sizes and the vendor programmed the replacement PSOM with the same code, as he should have.

If your speed sensor is located on the rear differential housing (exciter ring on the ring gear) this will only change the speedometer reading if you change tire sizes.

Changing the differential ratio changes engine RPMs and not speed. I can go 73 mph and pulling it into 3rd and with a 4:10 the engine RPMs really jump but the speed rev limiter does not kick in - to prove the point.

 

Tom, you are correct about programming the PSOM. The code change is only for a different tire size. Since the reluctor (read by the speed sensor) is mounted on the diff housing it reads _after_ the effect of the gear ratio so it has no effect. If the speed sensor was mounted in the tailshaft housing as it is in some other vehicles, then you would have to change the programing.

I am wondering if the speed limiter isn't kicking in. The PCM may be ignoring the speed sensor and reading the rpm in OD and determining that you are exceeding the limit and cutting it out based on engine rpm in OD alone. My van has a 98 mph speed limiter. I know because I have hit it.

Have you replaced the PCM? That may be your problem too.

Reference your quote above, my van had a 3.31 gear when I bought it and I would assume that is probably what yours had. That is the most common gear in a '94/'95 E150 5 liter. While it felt a little lazy with that gear it would pull OK and I towed with it for a few years and I always towed in OD. I changed to a 3.55 and that worked great.

I am thinking that if you are still having trouble pulling OD with a 4.10 gear then you have an engine problem. My van has 249,000 miles on it and I have had a couple of little things that caused power to fall off noticeably from time to time. First is a tune up. Plugs, wires, cap, rotor, filters, etc... If you haven't done them then start there. Next would be the twin cats. They are very restrictive and with that many miles I would bet they are partically clogged. I replaced mine with a single, high flow, unit and a free flow cat back system which really woke the motor up but if the cats are restricting flow that will kill your power. The intake system too is a problem. Clean the throttle body and intake track helps part throttle power alot and if you have any kind of EGR problem that too kills power. I recently replaced the EGR, the EVP Sensor and its vacuum solenoid along with cleaning the throttle body and intake manifold.

With 150K+ miles you are due for such maintenance. It would probably help to to do a commercial intake/fuel system cleaning like BG or TerraClean. That helps clean the intake and exhaust valves too and the get alot of varnish and carbon buildup on them with high mileage.

Steve
'95 Clubwagon XLT

 

mine came up 972 iam the guy with 3.73s van came with 3.48. I didnt find anything about reprogramin psom. am i looking in wrong place.

 

Ok heres my plan my van reeds the speed in two places sensor in side of tranmeasures driveline speed speed witch is know higher. it is also a hal efect sensor best i can tell. i just bought a older style speed sensor for an explorer off ebay this is the one that has the speedo gear on it simular to a speedo cable end my trans has a cap in this hole. i will put a 3.73 spedo gear on it and get my driveline signal from it. my ouput shaft has a gear machined on best i can tell from fingering around in it. it will be week end before i have everything. but i think it may work not out of much money if it dont.

 

Steve: That is good information. I had not thought about the computer reading OD AND RPMs. Last year I had a radiator leak so decided to pull everything and start with the water pump, all tune up parts as to the ignition and new wires, all new hoses (which gets expensive when you have a rear mounted AC/heater), radiator, thermostat, valve cover gaskets etc and then had it on a diagnostic computer several times and not logging any codes. The idea about the exhaust being restricted makes sense as the engines just feel plain restricted. Tom

 

Had a local mechanic cut out the cat and replace it with a Flowmaster cat with low restriction. Did not make any difference. So, I have eliminated that.

Tom

 

My Speedometer in my 94 f150 acts eratic only when I go over 70 miles an hour, then it jumps all over the place. I have replaced the sensor in the axle, and cleaned up the connections to it. I had been thinking it may be the cluster itself but my only affordable option would be to try a used one that may have the same issues, being that old too.

 

I replaced both sensor in axle and cluster in my 95 and it still does it. Mine was also dieing in reverse. I might try a different sensor.

 

After reading all the posts, here's what I think for what its worth:

1) You've changed sensors, but have had no change. O.K. Not a sensor problem.

2) You've checked sensor output - smooth and clean = "tone ring" seems OK

3) Check wiring to the PCM, clean, repair/replace anything that looks suspicious. Check ALL ground connections to make sure they are clean and tight. I wonder if a poor ground at a critical location could be responsible?

4) Still not working right? Check the PSOM calibration and proper operation. Is there a way to test the output of the PSOM to see if produces a consistent signal to the PCM?

5) If that checks out OK, then you need to look at possible PCM problems. The PCM processes the signals for both the speedo and cruise control. If it's got the hiccups then you're in trouble. I like the idea that the PCM may be comparing RPM, gear selection, and MPH to make a judgement about speed limitation.

It seems to me that if you've checked out everything else, that leaves only the PCM as a possible culprit.

 

Mines been doing it for years, it started with it dieing in reverse. It no longer dies in reverse but the speedometer still fluctuates at higher speeds.

 

mine still bounces around my fathers super duty does the same thing they replaced the tone ring and fixed his.