Ford E-450 "Drive by wire" ???

Drive-by-wire is the throttle scheme, nothing to do with steering and wander. Your replacement E-350 must have the caster set much more appropriately than the identical unit that was a wanderer.

I have a 2004 E450 and I can guarantee there is no drive by wire involved in the steering. As pauldub states, the difference in driveability is all in the +caster settings. In my opinion, the lesser +caster makes for easier steering for city driving but you want more +caster for best stability at highway driving speeds.

A couple of things come to mind...yes, drive-by-wire is commonly referred to when there is no throttle cable, but an electric motor drives the throttle plate at the intake. The accelerator pedal is just another input to the PCM and uses a TPS (throttle position sensor).

However this can also affect steering, since most power steering systems are variable boost, where boost is increased at low speeds to reduce steering effort when parking, and reduced at high speeds to increase control and road feel.

If the PCM was not properly reducing steering boost at high speeds, overboosted steering will produce a vehicle that is hard to control and wanders a lot, since steering input is magnified at higher speeds. This is likely what the Ford engineer was referring to.

The newest thing now is electric power steering. So instead of a steering linkage and hydraulic boost system, the steering rack uses and electric motor controlled by the steering wheel. Saves weight because you don't need a steering linkage through the firewall, no PS pump and associated plumbing, and no HP drain on the engine driving a PS pump. Brings new meaning to drive-by-wire....but they didn't have that in 2004.

Were you running the same type of front tire & the same front tire pressures on both?

Jim, "This program was brought to you by a series of unfortunate events."

Handbasket wrote:
Were you running the same type of front tire & the same front tire pressures on both?

Jim, "This program was brought to you by a series of unfortunate events."

I just wasn't aware of and "drive-by-wire firmware" on a E-450

BurbMan wrote:
The newest thing now is electric power steering. So instead of a steering linkage and hydraulic boost system, the steering rack uses and electric motor controlled by the steering wheel. Saves weight because you don't need a steering linkage through the firewall, no PS pump and associated plumbing, and no HP drain on the engine driving a PS pump. Brings new meaning to drive-by-wire....but they didn't have that in 2004.

I doubt very much if there is a car on the road with no steering linkage. This would be too dangerous. There has to be a mechanical connection from the steering wheel in case of an electrical failure.

I stand corrected, the new electric power steering does maintain a physical linkage, see here.

Back to the OP's question, just because the steering isn't drive-by-wire doesn't mean that electronics aren't involved in controlling the amount of boost. Overboosting at highway speeds will produce wander.

BurbMan makes a good point. Something to really look into and missed by many people!