LW4000 intermittent front impact

[GoBuckeyes]

Hi guys, looking for some guidance on this one...

One of our 4000's will intermittently turn short going across the front of the vehicle causing it to hit the drivers side mirror resulting in an impact. It has only done it 3 times, once in July and twice today. Each time it is the same. Vehicle pulls in, the first two passes of soap measure properly and then when it switches to HP it goes across the front but not quite far enough, turns 90 and gets hung up on the mirror shutting it down.

Here's what we've done:

In August it seemed like the trolley would sometimes hit the left stops so I put in a new Left Limit Prox.

Not sure off the top of my head but the X30 prox is less than a year old, tight to the picket fence and has no signs of physical wear.

Tires are in good shape and pumped up.

Why does it only happen on HP? First two passes work flawlessly. I'm not sure how to eliminate possible causes here.


Thanks

 

[whitescout]

The only thing that can make the arch turn early, is too many pulses from the #30 prox, or an input from the left limit. I would not only check the prox switches, but would check the prox cables as well. ( they are pretty cheap)

If it is only happening on a second pass of HP, I would inspect tires, rollers, and roller spacers, as you could be experiencing trolley drift.

 

[pgrzes]

I had a similar problem on my High Velocity. It was the prox wire where it went into the wego block! Was a pit azz to figure out!! There was a bunch of corrosion on the connection. I use a load of die-electric grease on every connection in the bay on my machine, totally coating all the insertion holes in wego blocks and all prox connections

 

[GoBuckeyes]

Thanks guys. Ill change those cables on Monday as it just did it again.

I also noticed that my VT board for that bay is the original software. Might be time to upgrade that too. I was told the newer software that uses the relay was a fix for count problems.

Merry Christmas

 

[Waxman]

changing out the prox wire is where i'd go instead of changing any software.

look at the simple stuff first. proxes and cables are common sources of trouble with travel / rotate errors on many automatics.