Zx td rev counter

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deian
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Zx td rev counter

Post by deian »

Hi,

Anyone know what the common causes of a non working rev counter is on a ZX 1.9td? It's be nice to know what the engine is doing.

Thanks
Peter.N.
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Post by Peter.N. »

Hi Dei

The usual problem is either a faulty TDC sensor or the wiring to it. The sensor lives on the gearbox end of the engine, just below the cylinder head. There are a pair of (or maybe three) wires that go into a connector on the end of the head, these connectors can get corroded, pull them apart and scrape the metal clean and apply a little grease, if that doesn't cure it, its probably the sensor.
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Post by deian »

Ok, that sounds nice and simple to fix, at least I don't have to fiddle behind the dashboard too much, thanks for that peter.

So this sensor, is that all it does? It's got nothing to do with the running of the engine?

Thanks
Peter.N.
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Post by Peter.N. »

Yours would be a purely mechanical fuel injection system, so, yes that's all it does. On the later electronic systems it may be used as a reference signal for the ECU.
deian
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Post by deian »

oki doki, thanks for that, mechanical sounds good, lets hope it likes veggie oil, 50 50 first
James.UK
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Post by James.UK »

I fixed my rev counter by... Undo all the fixings round the plastic trim- cluster surround, lower the wheel to bottom poss, unplug any-all switches located in the surround, pull the whole surround forward as far as you can and it should come out enough for you to get behind it. :)

I then tightened up the four lil nuts holding the case around the rev countercover and tried it by starting the engine (resting the surround on the dash top.) It worked! So I carefully put everything back and it's been fine ever since. (approx 3 months ish) :)

PS. It helps if you pull the speedo cable through the bulkhead as far as possible to allow the guage cluster max room to move...
.
James. (Nr M67 East of Manchester).
Dark Blue ZX 1.9D Auto 1994 'L' 5 dr (modified) Aura. 98K miles used daily. Ave mpg 40
Wedgewood Blue 75 CTD auto Connoissaur. 2002. 144k. used daily. ave mpg 40 ish.
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oscarloco
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Post by oscarloco »

Mine was doing crazy things. The revs stayed static around 2500 even tough the engine was above or below that. Or it would jump from 1000 to 2500 and back to 1000.

The cure? Clean the battery terminals and replace the cheap lead clamps with better bronze ones.
Oscar Lopez
'94 ZX 2.0 8v petrol (restoration to its former glory on its way after being neglected by stupid Ex)
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Post by elma »

On my car it was the sensor on the flywheel.(i think that is the tdc one)
It is taken out from underneath the car but is unplugged from under the bonnet.
I removed the airbox so some light got down there, jacked up the front.
Lay underneath on my back with legs sticking out of the front of the car.
With my head positioned in the middle of the car the os driveshaft was about in line with my chin. From here you can see the sensor going into its little mount by the flywheel. This is all if you look a bit to the left.
It undoes with one bolt (10mm or 13mm i think)
Then its fiddly to get out, but it does come. Its a friction fitting which the bolt pinches tight so it doesn't need unscrewing all the way.

The wire is plugged into the (i think) brown connector underneath the airbox.
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Post by deian »

Thanks for all the replies, I recently cleaned and tightened the battery terminals, so it's not that oscarloco, but it's here for reference for others :wink:.

I will do the easy thing first, pop under the car to look for the sensor and check the wiring and plugs going to it. Elma, your descriptions are quite excellent, I will do some stuff tomorrow. Thanks to all of you so far.

James, fiddling behind the dash will come last, but I reckon it will happen quite soon as a bulb needs replacing behind the dash, but easy thing first.
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Post by elma »

Don't worry about taking out the dash, its no chore at all. Only pain is if you have to wait first for airbags, one of the reasons i prefer the '94 cars.
I reckon the sensors your best bet, may even just need adjusting not replacing. Problem with mine was someone had adjusted it too close so the end had been whacked to bits by the flywheel.
If you look over previous threads you can test it with a multimeter but its a ten minute job to change so I didn't bother as I knew my spare sensor worked for sure.
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Post by deian »

Thats ideal, no airbag in mine either, just wondering how much slack there is for the speedo cable and the cables behind, last time i fiddled behind a dashboard was on a pug 106 checking the speedo cable out, but the thing was real tight... any tips would be great.
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Post by elma »

Aah, just wrote you a reply then read the thread properly.
Semi disregard what I just said, Its probably very similer but I assumed you were talking bout a xantia. I've never even been in a zx so I shall go and be quiet now.
deian
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Post by deian »

can't be as hard as a xantia no.
elma
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Post by elma »

Well on a xantia its really easy, so I hope its not then you'll have an easy day.
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