TD5 clutch switch

|| Recently, I had to have the clutch master cylinder on my 2004 TD5 || Defender changed under warranty, due to a fluid leak. Since then (6 || weeks), I have had two occasions when the engine has run unevenly || and jerkily at highway speeds. In the most recent example (last || Wednesday), I was driving in the country, and the engine was running || quite badly for about 50 Km, until the orange engine warning light || came on, and I lost throttle control. I checked for obviously loose || plugs etc., and remembering the clutch master cylinder change, || unplugged the clutch switch. || || All was back to normal after restarting, and since then, the car has || run faultlessly. || || My question is, could intermittent opening and closing of the clutch || switch contacts, while driving, cause engine hesitation, and the || warning light? It does seem unlikely, but any information would be || appreciated.

ISTR the clutch switch sends signals to the ECU for the anti-shunt feature, which temporarily reduces fuelling when you operate the clutch to make for smoother gear changes. If the clutch switch is duff and sending the wrong signals, this might explain why you're getting problems with power, warning lights etc.

BICBVVW.

This is probably the same switch/algorithm which caused the lack of power when pulling away in early DII's. Busy junction, gap appears, try to go and despite having your hoof flat on the the floor on the accelerator pedal you would chug sedately out into the flow at little more than idle. And then the computer would suddenly say "Ok, he really does mean go" and you'd blast off with acceleration that would have impressed Captain Kirk, only to have to tread all over the stop button again because you were now travelling too fast for the traffic stream you'd just pulled out into. Computer programmers, pah!

Steve

Steve wrote:

|| "Richard Brookman" wrote || in message news: snipped-for-privacy@individual.net... ||| Graeme Evans wrote: ||| ||||| Recently, I had to have the clutch master cylinder on my 2004 TD5 ||||| Defender changed under warranty, due to a fluid leak. Since then ||||| (6 weeks), I have had two occasions when the engine has run ||||| unevenly and jerkily at highway speeds. In the most recent ||||| example (last Wednesday), I was driving in the country, and the ||||| engine was running quite badly for about 50 Km, until the orange ||||| engine warning light came on, and I lost throttle control. I ||||| checked for obviously loose plugs etc., and remembering the ||||| clutch master cylinder change, unplugged the clutch switch. ||||| ||||| All was back to normal after restarting, and since then, the car ||||| has run faultlessly. ||||| ||||| My question is, could intermittent opening and closing of the ||||| clutch switch contacts, while driving, cause engine hesitation, ||||| and the warning light? It does seem unlikely, but any information ||||| would be appreciated. ||| ||| ISTR the clutch switch sends signals to the ECU for the anti-shunt ||| feature, which temporarily reduces fuelling when you operate the ||| clutch to make for smoother gear changes. If the clutch switch is ||| duff and sending the wrong signals, this might explain why you're ||| getting problems with power, warning lights etc. ||| || || This is probably the same switch/algorithm which caused the lack of || power when pulling away in early DII's. Busy junction, gap appears, || try to go and despite having your hoof flat on the the floor on the || accelerator pedal you would chug sedately out into the flow at || little more than idle. And then the computer would suddenly say || "Ok, he really does mean go" and you'd blast off with acceleration || that would have impressed Captain Kirk, only to have to tread all || over the stop button again because you were now travelling too fast || for the traffic stream you'd just pulled out into. Computer || programmers, pah! || || Steve

Yup, that's the one!

The upside of it was the anti-stall feature that *increased* the fuelling if it detected a load reducing the idle speed (eg extra load on the alt, or starting the aircon). It made crawling in traffic a doddle, as you could do it all with just the clutch, as long as you weren't too brutal.

Yup, it's got me a few times. I've always put it down to turbo lag rather than the fly by wire nature of the engine though. I generally just wait for a bigger gap, my boy racer days are a few years back.

I did have to take off a bit quick the other night though to get across the traffic on the A69, I did remember to wind the revs up to 2,000 or so before letting up the clutch and off she went with none of that hesitation, much to the surprise of No.1 Son (age 6) in the back who accused me of speeding and I was lucky that there wasn't a Police car about...

Yup, use that all the time when slowly manouvering or in traffic. Pick a suitable gear for the speed you want to pootle at and away you go.

None of this helps with the OPs problem but I have noticed that mine occasionaly goes a but lumpy for a few seconds when just driving along. Where is this switch again?

While we're on the topic, what does the throttle position sensor do on a

300Tdi Disco? I've been playing with the diesel pump settings with a good deal of success but would like to understand a bit more. TonyB