Troubleshoot this weird car problem
 

I noticed recently that the driver's side windshield wiper on my car will "whip" too far to the left (your left as you are sitting in the driver's seat). I immediately assumed that some piece of the wiper assembly had worked its way loose. This turned out not to be the case.

What I've discovered is that it only happens when the car is moving! If the engine it turned off, or if it's on but idling, the wiper works fine, stopping about 3-4" from the left edge of the windshield. But if you're driving down the road, then you have the problem. (It usually gets worse with time--when you first turn the wiper on, it's OK. After a half dozen or so swipes, it's bumping into the edge. Another half dozen, and it's actually skipping over the edge.)

Any suggestions? It's kind of hard to reach out and examine the wiper blade when both the wiper and the car are in motion . . . .

If it does this crazy thing, and then you pull up to a red light and stop, does it behave normally again?

For the amount of time that I'm sitting at the light idling, yes. Once the light turns green and I start moving again then the whole process repeats.

Are you going faster than warp factor 6?

This is a 1995 Ford Escort. I'm lucky to make it to 1/4 impulse power. :D

Oh yeah, you can also "start over" by turning the wipers off for a bit. When you turn them back on, they will behave for a few swipes before going crazy again.

Gearing in the mechanical box thingy that operates the timing of the blades. You probably have a worn down tooth or two. This is the step before "goes totally wacky and out of sync."

You probably don't just turn the wipers off, right? You're a precise kind of guy, so you let the wipers complete a cycle and end in the down position ... so you're starting off at the (roughly) same point in the cycle each time. The teeth are not entirely gone, but worn low enough that when your blades catch some wind it overwhelms the gearing system and hurries it along.

(I have no idea. I'm talking out of my ass. My secretary just had the wiper gear box go on her car and that's how it acted)

Does it do this on intermittent as well as normal setting?

Pie, it does, but it takes longer to work itself into a frenzy.

Wolf, the gear business actually sounds reasonable to a certain extent. I'm not sure it explains the way the wiper goes farther and farther to the left even if you're at a fairly constant speed. I'm also not convinced that, if it's a gear, it wouldn't jump at least occasionally even when you're sitting still.

this is an indication that the car is ready to be traded in for top dollar....on say, a Sentra?

"Top Dollar" on a 95 Escort wagon is, what . . . $150?

depends on how much gas is in the tank.

So how do you get it back? Do you physically move it back to a properly parked position?

No. It fixes itself once you turn off the wipers.

No. It fixes itself once you turn off the wipers.

Wipers have a Home position , when you turn off the wipers the controller brings both the wipers back to home position , I suspect that you have a worn gear at its outermost position ,

as LJ said time to trade UP

If a gear inside the wiper motor was stripped, then home switch would occur when wipers were in different locations.

Other 'gear' would be a shaft that connects wiper blade arm to 'rotating back and forth' wheel. If that was slipping, then wiper arm would stay just as far from home position as wiper arm has overreached left side. IOW you could move wiper blade back to a home position manually.

I am assuming you have a Ford blade arm - did not buy a new wiper blade holder because you bought some third party (Anco, Trico, etc) wiper blades? Sometimes these third party blades are not the right size - but close enough for the Pep Boy, et al customer. (If using Ford blades, then blades would not be replaced so often - saves money.)

That leaves something shifting in the arm(s) that connects wiper motor to the 'rotating back and forth' wheel. For example, go to where wiper blade arm attached to shaft from that 'rotating back and forth' wheel. Is the nut on shaft beneath that wiper blade arm still tight? Turn on wipers with ignition switch until blade is partially across windshield. Stop the wipers half way using the ignition switch. Now, grab the blade arm at its base. Is that shaft (through car body) firm or can you shake it?