Don't scrap that diesel car just yet!!

[ARW]

And they are never learnt how to drive without a clutch.

[ARW]

taunt not learnt

[Bob Eager]

One of the first things I taught myself. I once had an old Morris 1100 and the clutch system failed somewhere north of Braintree. I got it all the way back to Canterbury with the clutch permanently engaged. That included throwing the money at the guy in the toll booth at the Dartford Tunnel, without stopping...

[The Natural Philosopher]

No. You stop and stall the engine on the brakes, engage first gear and then startt the engine in first.

Easy peasy.

[Richard]

OK. You've had your apprentice correct your typos.

[Bob Eager]

That's how I got started the first time. I didn't want to risk it in heavy traffic.

[dennis]

I think we have been here before, Bosch probably provide example code just like many other manufacturers do. They almost certainly have a tool kit that allows others to modify the example code just like other manufacturers do. Exactly why you think a group like VW wouldn't be able to or not want to write some of the code is the issue.

[Tim Streater]

The trouble with Our Dave is that he lacks imagination. The Party says that Bosch should write all the code for its customers, so that there might be an option as you say for Bosch to provide a kit allowing the customer to write its own software to drive the product is forbidden. BY ORDER!

After all, we've always been at war with Eastasia. Errm, haven't we?

[ARW]

Not in a loaded Scudo.

[Chris Bartram]

I taught myself that after my dad described it, practiced in a work van :-). Managed Birmingham City Centre to the VW dealer at New Oscott when the cable broke as I was leaving the car park. A couple of tricky moments, it was near rush hour, but thankfully less traffic in those days, can't imagine doing it now. Changed the cable on the car park at OH's work.

[Dave Plowman (News)]

Thanks for confirming you know less about industry than most things. No wonder you voted Brexit.

[The Other Mike]

Directly triggered rev counters from an ignition coil are a remnant of the

1960's and 70's with either a contact breaker or a contactless system but still using a distributor. Last car produced with contact breaker? 30 years ago? Last car with a distributor 20 years ago?

The commonly used means of acquiring an engine revs signal requires signal processing for measuring the passage of the toothed wheel and the position of the missing tooth on the crank or cam. It then uses this to synchronise the spark and fuel injection elsewhere in the ECU.

By the mid to late 1980's the crank pulse detector fed the ECU, that then triggered an (often external) external ignition coil pack and that unit often fed the moving coil revcounter with a suitable loop current or a PWM signal.

But when everything is in the digital domain it's often easier, cheaper and more reliable to send everything to the dash over a thin twisted pair to operate a dozen warning lamps and half a dozen gauges than use a huge bunch of discrete wires.

Rev counters and indeed most dash gauges including speedos nowadays are either driven by stepper motor or are a visual widget on an LCD display.

[NY]

Quite possibly. But, irrespective of how the signal reaches the dashboard and how it moves the needles on the gauges, I'd still expect the feed for the gauge to be from a crankshaft rotation sensor that is also used for determining timing of fuel injection and (for petrol) spark. Likewise I'd expect the speedo to be driven from a wheel-rotation or final-drive-rotation sensor. I suppose you could drive the speeo from a GPS receiver and give a true reading, but you'd still need the wheel rotation as a fall-back in case of loss of GPS.

Doing it any other way seems unnecessarily complicated.

[Dave Plowman (News)]

Of course. What I meant is I can't see any reason to 'frig' its reading, unlike with other gauges, as I explained.

[Dave Plowman (News)]

Point I was making was that I can't see any reason why you'd want a tach to read anything other than true engine RPM. No point in fitting one unless it's reasonably accurate. After all a rev counter is of zero use to many drivers. For those who can make use of it, needs to be reasonably accurate.

[The Natural Philosopher]

No, They are normally analogue millammeters. Driven by the cars computer systems.

[Andy Burns]

Mine (7 years old) certainly is a stepper-motor, the speedo and rev needles do a precise 'sweep' as part of the lamp check sequence when turning the ignition on.

[Tim Streater]

When looking for a new car 18 months ago, I rejected one model precisely because it does that.

[Huge]

Add another topic to the oh-so-long list of those that Turnip either knows nohing about or generalises from his limited and elderly experience.

And some modern cars don't have any physical dials at all.

[Andy Burns]

Of course, mine has the option to display a reasonably large digital speedo on the dash, which I tend to find easiest to read, especially since '30' does get a figure on the analogue dial.

Since someone has mentioned 'fudging' e.g. the rpm dial, I feel the digital speedo must do quite a lot of smoothing, as it never 'flickers' between a number and +/- 1mph