Odo clocking

[Guest Ash]

 

 

 

The odo reading can be altered by feeding it with a signal generator. Problem is, you can only go up. When you reach 999,999 the unit will latch. Meaning, it won't roll-over to all zeros. Plus, it takes ages (weeks even) to clock the odo by a million miles.  

 

Now, you can feed the chip with a faster clock signal which *considerably* speeds up the process. Anyone who understands digital electronics will be able to do it. But it's a difficult job isolating the various pins and so forth. (I very much doubt your average auto electrician would have the ability, which makes me wonder whom JIC uses to do their clocking).

 

By feeding the chip with a faster clock, you can count the odo up *much* faster. Though when I was experimenting with mine, I *uggered one of the characters on the display. So in the end I had to buy a UK one and clocked it to read the equivalent miles.

 

As a matter of interest, I clocked my old unit to as high as it would go and, sure enough, it latched at 999,999.  

 

The theory I came to, at the time, was that the units might not latch *if* they are clocked fast enough.

 

From memory, the maximum frequency you can clock it is about 1K. But if you play around with the inputs direct to the chip you can clock it at about a 1 Meg or something. But there's a lot about that theory that just doesn't sit right.

 

If it is true, the the latch was fitted to later cars as someone has suggested, then why did it happen with my car? Not only that, how can JIC do it with the late-model cars that they generally sell?

 

Yours,

J

 

 

[Paul Booth]

 

Why bother Ash, they're only £60 to buy?

 

[Peter Betts]

I agree with Ash's comments and I know we've spoken about this a long time ago :-)

It is possible using the pulsing method but I'd like to know how JIC get it done.

But as Paul says, at £60 for a new one (didn't know they were so cheap?) why bother. That more than covers the time spent on doing the other mods.

[Guest Ash]

 

 

Paul, I'm just curious that's all. It's one of those MKIV-mysteries I haven't yet solved.

 

Yours,

J

[Paul Booth]

 

I would suggest that JIC *don't* do it for every car. Toyota in Redhill tell me they still supply the odd odo (sorry) to JIC.

 

They're about £52+VAT.

 

[Digsy]

I've been wondering about this clock forward / clock back / UK odo thing ever since Paul talked to Steve and since Ash posted saying that the odo cannot be clocked backwards.

 

Basically, I've been going over the information *as it was told to me* by JIC and their conversions guy (Andrew), rather than how I may have interpreted it.

 

I have come to the conclusion that the most likely scenario as it was described by Paul: JIC do not in fact clock their odos back to the equivalent miles reading, but instead fit a new modified or UK spec odo which is clocked forward to the correct reading. This would fit with the known facts, get around the latching problem, and also take a lot less time.

 

When Steve and Tim told me that they adjust the odo figure to read the equivilent  miles I assumed that they clocked it back, rather than use another method such as fitting a new odo - just because it seemed like the simpler soltuion at the time.

 

I openly admit that I don't know a huge amount about electrical engineering, so I try to make a point of only repeating information that I understand to be correct, and which can be independantly verified from learned sources such as Paul, Ash, and Pete. In this case I simply put two and two together and got five (or five-eighths!).

 

Sorry if I clouded the issue at all.

 

[Guest Ash]

 

 

Darren, no problem at all. To a layperson all this talk must seem confusing.

 

It's just that about 2 years ago there was a big discussion about clocking the MKIV odos. Myself and a few other people were trying to solve the problem of the extra miles that are created as a result of changing the legend on the odo to state MILES instead of KM's.

 

In my mind, there is still the big mystery of how someone can send the units forward to all zeros and then being counting up... when in my experience all they did was to latch.

 

I thought that maybe some explanation from JIC might help throw some light on the issue.

 

Yours,

J