I just had my first opportunity to haul a real load with my '97 F-250 (460, E4OD, 4.10 gears, stock size 32" tires) and I found it almost impossible to use the cruise control at 70 mph. With my slide-in camper in the bed and my Bronco flat towed behind, on just about any hill it would downshift relatively violently.

By contrast, back when I had my '95 F-150 (351, E4OD, 3.55 gears, 33" tires) I could haul a similar load much more pleasantly. Granted, the F-150 weighed a bit less than the F-250, and the Jeep I towed back then weighed less than the Bronco, so I probably had about 1500 lbs less weight (maybe about 10,500 vs 12,000 lbs). But I don't think that was the biggest difference.

When the F-150 started up a hill with the cruise set at 70 mph it would give it some more gas, but the speed would drop some too. When it got down to about 60 mph it would downshift, but it didn't get that low on most hills, and when it was getting close I could tell and would kick off the cruise so the downshift wouldn't be quite as harsh.

The F-250 on the other hand will keep it at 70 mph as it pushed the throttle to near wide-open, and will give very little indication that it's about to shift, so I couldn't always kick off the cruise before it was snapping our necks back at full throttle in third gear.

I know it might sound strange to complain that a cruise control is too good at holding speed, but I know I'm not alone in this. In fact the guy at the campsite next to us on this trip was talking about how much he loved the motorhome he now had because the cruise would let it slow down a little on hills rather than always having to downshift like his old one.

So my question. Is there anything that can be done to adjust a cruise control so it doesn't try so hard to keep the speed right at the set point?

 

Once that throttle plate opens up on the 7.5L you're going to get a downshift at the E4OD --- that's perfectly normal unless you believe that downshifting is harsh/harder than normal --- if so, there are other areas to investigate.

As for adjusting the cruise control to do things Ford didn't intend, I wouldn't go there............it's a tight loop system and altering parameters in one part of the chain (e.g. bead chain, servo, amps) would surely introduce unexpected or unintended consequences elsewhere........

 

I know I'm going to get a downshift. I don't like that it happens automatically (I wish I had a manual, but after looking for about 3 years unsuccessfully I settled for an auto), but my '95 F-150 with an E4OD was a whole lot less annoying than this, so I'm hoping I can get closer to how that truck drove.

Yeah, I don't want to get into trying to mess around with components of the system. What I was more hoping for was something like a chip or whatever that lets you reprogram the engine (and/or transmission).

And it's not that the trans is shifting badly, it's just that going from wide open throttle in 4th gear with the torque converter locked to WOT in 3rd gear with the torque converter unlocked is a VERY noticeable change in acceleration. It shifts much more acceptably if I don't have the cruise control on. Then I let it slow down some, and when the speed gets too low it will downshift, but not being held at WOT by the cruise it doesn't snap your head back.

And that was my solution on this trip, I just didn't use cruise control. But I'd like to be able to, and I could on my '95.

 

The issue is your going up hill in overdrive. Is is much like towing a trailer with the Bronco and the camper on there. If you read the owners manual it says to lock out overdrive when your pulling a trailer, especially up a hill.

 

Granted, I could take it out of overdrive on hills, but that's more monkeying around than taking the cruise off on hills, and it pulls hills fine in overdrive if it's not on cruise and I let it slow down a little.

Or I could just leave it out of overdrive all of the time when towing, but with the 4.10 gears that gets a little buzzy, and isn't the greatest for mileage.

And again, my previous truck with a smaller engine, taller gears, slightly taller tires and the same trans worked much better. I could pull hills in overdrive, cruise set at 70 but speed sagged down to 65 or so, that my current truck is slamming into third on.

 

I can not comment on your old f150 but pulling that kind of load in hills using cruise is not really going to work well. On these older trucks it makes it shift to much. I think its fine on the flats but I would just manually drive it when towing in the hills. You will get better mpg also

 

Take it out of OD on the hills. Plain and simple

 

Thank you all for the advice on when to use or not use cruise control.

And I'm assuming from the lack of response to my question that no one knows of a way to adjust how much "authority" or gain a cruise control has.

 

That is correct.. it would be a custom electronic project I would think.

 

I seriously doubt Ford made provisions to adjust controller gain. That would cost an extra $0.15 per truck for a trim pot or equivalent hardware. If you're dead set on finding out, crack the controller open and have a look around. You'll be able to tell real quick whether the design engineer intended anything to be adjustable.

You could also just replace the controller with whatever you like. You'd have to find one that can work with the existing I/O (speed input, switch inputs, servo output) or better yet just re-do the entire thing! Be a fun project if you like messing with electronics. Create a PID loop, test, debug, and enjoy!

 

OK, thanks. I'm not that into electronics to try it myself. I was hoping that with all of the aftermarket programmers / controllers available for engines and transmissions that maybe a company might have already done the custom work.

 

To start with the engine and PCM computer does not even know the Speed Control module is even there. We call it Speed Control in this era of the Ford model and not cruise control.

It does sound like there was something wrong with the Speed Control module in your 150 as it should have not let the speed to drop to 60 when set at 70. I have had to replace the speed control module for doing that.

Your TPS (Throttle Position Sensor) sends a voltage to the PCM computer and the PCM computer only knows of the voltage levels from the TPS. They are CT (Closed Throttle), PT (Part Throttle) & FT (Full Throttle).
•Closed Throttle can be anywhere between 0.6-1.0 volts
•Part Throttle is triggered @ 0.04 volts above Closed Throttle
•Full Throttle is triggered @ 2.71 volts above Closed Throttle

When your speed starts to drop the Speed Control Module opens the throttle and this turns the TPS to try to maintain the set speed and when the voltage hits FT from the TPS the computer looks at its tables and decides if it can down shift or not from the speed information from the PSOM and the engine RPM from the PIP sensor. It has no idea that you are using Speed Control, it just knows the throttle has opened to FT.

There was a post on here a while back that the poster said that he adjusted the TPS voltage and the speed control worked more like he wanted it too. I do know if this works or not as I have not tried it. But I do not see how it could as when you start the engine each time the computer looks at the voltage from the TPS and saves that reading as CT. So if he adjusted it he would only be adjusting the CT point and he should still get FT at the same point above CT.
This is why you can not touch the throttle when you start the engine. Note that FT during cranking will also shut off the injectors for starting a flooded engine. Then you should shut it back off and restart with a closed throttle.

 

You can also damage the transmission by towing in OD to begin with; you can also lug (and damage) the engine by going up a hill in OD and the RPM drops too much.

On trucks this old, 1000lbs difference can cause huge changes in behavior.

 

Someone earlier (1990 F350) said to not mess with the speed control and I agree. Someone else (Conanski) said it would be a custom electronics project and I agree along with the fact it would be a dangerous project.

There is a discussion about adjusting TPS and I'd stay away from that too as it's a direct potentiometer input, based on throttle plate angle, to the EEC-V.

 

This is an old wives tale and needs to stop being passed along.
The ONLY time you hurt the transmission when towing, is when it's hunting for a gear. It's the up/down shifting every 30 seconds that's harmful. New trucks don't even have an od off button. The only way to damage an engine by lugging it down under load is by detonation/preignition/knock/pinging. Which that means your timing isn't set right or you have poor fuel. EGT on a diesel is more of an issue than gas engines, and a higher rpm can help.

Tow in overdrive on highways and when cruising around town. Low speeds, up/down hills and when it's hunting for a gear, lock out overdrive.