Need urgent help with stalling ZX

nistelrooy · Post by **nistelrooy** » 16 Feb 2004, 16:28

Hello All! Okay this problem has been making me tear my hair out. Its been going on for 4 months, and none of the local mechanics seem to know whats wrong.
My '94 2.0 ZX volcane tends to stall when i'm slowing down to a stop. While slowing down, as I shift to neutral, the revs will start to dip very low until i see the battery sign (symbol of a battery at row of warning signals. what does it indicate?) start flashing on the dashboard before the revs start catching up again. Sometimes the revs don't go back up and the car stalls.
Also, when the car gets in this mood, the revs will dip really fast and low whenever I downshift, even at highway speeds, followed by the flashing battery sign.
The problem seems to be random. On somedays the car runs fine, i can get stuck in the crawling KL traffic and it stops and moves without a fuss. I've also noticed that after a bout of hard driving (i.e shifting at the red line), the same symptoms appear: revs dipping, warning lights etc. when i have to stop.
I've had the throttle body cleaned numerous times, had the vehicle speed sensor, stepper motor and MAP sensor replaced but the problem still persists.
I took the car for a ECU diagnostic test and the results were a faulty ignition coil and knock sensor. Does this have anything to do with my problem?
Please help!

AndersDK · Post by **AndersDK** » 16 Feb 2004, 16:58

The battery icon would be the chargelamp.
It has nothing to do with the problem - other than the engine revs that low - that the generator can not provide a charge - hence the warning lamp. You should see this warning lamp also with ignition on initially before starting the engine.
I can't believe the ignition coil would be responsible for stalling at low revs - as this would also make for problems at higher revs.
The knock sensor (is this really fitted to a ZX 2.0 engine ??) may do some weird things if the sensor or it's cabling is at fault.
Otherwise I'd suspect the "trouble" (throttle) potientiometer on a 10y old car with these indications.

nistelrooy · Post by **nistelrooy** » 16 Feb 2004, 17:48

Thanks Anders.
Yes, the knock sensor is fitted to the ZX 2.0 8 valve engine. I read a section on it in the Haynes manual.
Will a faulty potentiometer show up on a ECU test? Is it expensive (i know i live on the other side of the world, but a general price please) to replace?

AndersDK · Post by **AndersDK** » 16 Feb 2004, 17:59

AFAIK you only have the throttle potientiometer as ECU fault code in rare cases - simply by the nature of this component.
The ECU will only store faults of more permanent nature - intermittent or random faults are not always stored.
My guess is a new TP is approx £25 from GSF.

nistelrooy · Post by **nistelrooy** » 16 Feb 2004, 18:12

Okay,
what would explain the charge lamp warning light coming on when i downshift sometimes?

AndersDK · Post by **AndersDK** » 16 Feb 2004, 18:20

Either low engine revs - thereby low generator revs - and low (insufficient) charge.
Or the generator fails randomly due to worn out brushes in the regulator module - not unlikely on a 10y old car.

nistelrooy · Post by **nistelrooy** » 16 Feb 2004, 18:33

Pardon my ignorance, but where exactly is the generator?

nistelrooy · Post by **nistelrooy** » 16 Feb 2004, 18:40

Are you refering to the alternator?

Guru Meditation · Post by **Guru Meditation** » 16 Feb 2004, 19:25

The idle stepper motor is known to cause problems on 306/ZX 2.0 8 valve, leading to problems such as you describe ie refuses to idle, these problems also occur intermittently-it'll be as good as gold for ages then some days everytime you declutch it will stall. My friend has an 'M' reg 306 XSi which has similar problems.

AndersDK · Post by **AndersDK** » 16 Feb 2004, 20:15

Generator = alternator
- got mixed up in english & scandinavian expressions [:I]