Citroen ZX (1992 - 1998) - 1994 1.9TD - intermittent tacho

Honest John Back Room » Technical matters
View Threaded
Thu 17 Jan 2008 13:06
1994 1.9TD - intermittent tacho - whodee
I've searched but not found the answer to this prob'.

I've a 1.9TD '94 plate with 150k ish on the clock. The tacho has begun to operate intermittently. It may be effected by temperature as it seemed to be working better during the cold snap a month or so ago. It also can be made to operate if the engine revs quite high.

Ive removed the tacho to see if there's anything obvious wrong there and found nowt. I've read about problems with the TDC/Crank angle sensor and have been told that if that was faulty the engine would misfire. Tho' I can't see from the wiring diagram in my Haynes that it's actually connected to the EMS and there's no mention of it in the fuel/ emission control part of the book either.

So, anyone have any ideas? If it was the sensor can I test it? It seems that a new one can be bought for less than twenty quid so it's almost worth just trying it. Now if I can just find the bloomin' thing!

Any help appreciated, thanks.

Edited by Dynamic Dave on 17/01/2008 at 13:35

Reply | Report as offensive | Link
Thu 17 Jan 2008 15:05
1994 1.9TD - intermittent tacho - RichardW
A 94 TD is purely mechanical - the crank sensor exists only to run the tacho. You will see it if you get the car on ramps and look up the back of the engine at the flywheel end - it's about half way up the bell housing flange, held on by a small (10mm probably) bolt. It might just be the end of the sensor is crudded up, or the cable connection may be dodgy. Pull the sensor out and clean it, and then trace the wire back and check the connector - may be enough to fix it. Like you say, a new sensor is unlikely to break the bank if it does need to be replaced.
Reply | Report as offensive | Link
Sat 19 Jan 2008 19:24
1994 1.9TD - intermittent tacho - whodee
Thanks for the info. I didn't think the sensor was for anything other than the tacho. I'll get the car over my pit as soon as I get a mo'.
Reply | Report as offensive | Link
Sat 19 Jan 2008 20:21
1994 1.9TD - intermittent tacho - blue_haddock
My 205 TD did exactly the same thing and it was the sensor on the box at fault. Wjip it out and clean it up and you'll be ok for a while.
Reply | Report as offensive | Link
Mon 21 Jan 2008 13:29
1994 1.9TD - intermittent tacho - whodee
Another job done!

Found the sensor and connector.
The sensor was a bit cruddy on the end but not enough to stop it working, or so I thought.
Wiped it clean and cleaned up the already clean looking connector and a working tacho is the result. Fab.
Now, how long it continues to work is a different thing but at least it points the finger at the sensor and not the gauge or circuitry behind the instrument panel. The sensor is a lot easier to get to.

Thanks for your contribution guys.
Reply | Report as offensive | Link
Mon 21 Jan 2008 18:56
1994 1.9TD - intermittent tacho - Peter.N.
It could be bad connections on the plug.
Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide

From which small car to buy at which price point to the best UK-built cars, our Top 10s have the lot. Click now for your shortlist.

Unsure of what to buy? Our Top 10s are here to help you....