my little '93 ax 1.0l has been playing up for a while now. It all started at the end of summer when the idle went all wacky revving all over the place. After a few days this got better and then everything was normal again. It appeared again a couple of months later but this time with large flat spots early in the rev range and the engine sort of hung onto the revs like the throttle cable was sticking (checked but not). Disconnecting the battery to reset the ecu would cure this for a couple of days and suddenly the problem dissapeared again.
Ok so all was fine until something in the car decided to drain the battery and the car was left with a flat battery for a week or so as it was not in use. I charged the battery and started the engine, but ever since the idle has been really rough like its not running on all 4 and the fuel consumption is up.It seems fine at mid to high revs tho. I have noticed that there are some exhaust gasses leaking from where the manifold meets the downpipe but this is nothing severe.
Could this be the slow death of my ecu? would these symptoms suggest this? or is a sensor at fault? I replaced the solenoid on the front the the throttle body but no difference.
any ideas?? thanks, tris.
p.s there is still something draining the battery but this may not be related, just bad luck!
ax engine electrics
Moderator: RichardW
Could it be water in the fuel ? Try some alcohol in next tankfull.
Does the ECU fault lamp come on as lamptest when key turned (bulb working) ?
There are many standard service issues that can cause the symptoms.
Battery drain :
Take a careful look at all things from outside in dark hours (not opening doors and activating any courtesy lights). It will be possible to see if glovebox/boot/engine bay lights are held on.
Use the old trick running the engine idle when dark. Any arcing from ignition components is clearly seen then.
Put any electronics dingies in the car lately ?
Does the ECU fault lamp come on as lamptest when key turned (bulb working) ?
There are many standard service issues that can cause the symptoms.
Battery drain :
Take a careful look at all things from outside in dark hours (not opening doors and activating any courtesy lights). It will be possible to see if glovebox/boot/engine bay lights are held on.
Use the old trick running the engine idle when dark. Any arcing from ignition components is clearly seen then.
Put any electronics dingies in the car lately ?
Anders (DK) - '90 BX16Image
Hi,
if the ecu bulb is the left of the dash and coloured orange during the lamptest then yes it is lightinhg up. At the moment the battery is too dead to start the car so i cant check for arching.
I have made no new additions to the electrical system. think the only thing drawing power is a rather noisey clock. I did have problems last week with the interior light not coming on unless it was tapped but other than that nothing seems to stay on.
if the ecu bulb is the left of the dash and coloured orange during the lamptest then yes it is lightinhg up. At the moment the battery is too dead to start the car so i cant check for arching.
I have made no new additions to the electrical system. think the only thing drawing power is a rather noisey clock. I did have problems last week with the interior light not coming on unless it was tapped but other than that nothing seems to stay on.
I imagine you have the magnetti-marelli throttle body fuel injection system on your car - in which case if its similar to the one fitted to the BX 14 you will have a throttle potentiometer - basically a variable resistor like a radio volume control operated by the throttle.
From what you describe I'd guess its worn out and got noisy. You may be able to test it with a multimeter by passing current through it (resistance setting) and see if its nice and progressive. If its in any way jerky - its knackered. You may be able to dismantle it and clean/re-align everything but I've never seen one and have no real idea.
If the tests Anders suggests for tracing the electrical drain get a test bulb and connect it into the earth lead and see if it lights up with everything turned off. If it does - hunt by first pulling all the fuses then disconnecting suspect bits until you find the drain. If the drain isn't sufficient to light the bulb leave it in place and connect a multimeter set for volts accross it. The bulb will then function as a resistance and you will be measuring the current accross it.
Its not a good idea to take a direct current reading unless you are sure the meter is not going to be overloaded. The 10Amp settings are unprotected and a mistake can blow the meter instantly. The lower current ones may be protected but are very sensitive for the huge currents available in car electrics.
Some small background drain is to be expected but it should not be much. (less than 100 milliamps?)
From what you describe I'd guess its worn out and got noisy. You may be able to test it with a multimeter by passing current through it (resistance setting) and see if its nice and progressive. If its in any way jerky - its knackered. You may be able to dismantle it and clean/re-align everything but I've never seen one and have no real idea.
If the tests Anders suggests for tracing the electrical drain get a test bulb and connect it into the earth lead and see if it lights up with everything turned off. If it does - hunt by first pulling all the fuses then disconnecting suspect bits until you find the drain. If the drain isn't sufficient to light the bulb leave it in place and connect a multimeter set for volts accross it. The bulb will then function as a resistance and you will be measuring the current accross it.
Its not a good idea to take a direct current reading unless you are sure the meter is not going to be overloaded. The 10Amp settings are unprotected and a mistake can blow the meter instantly. The lower current ones may be protected but are very sensitive for the huge currents available in car electrics.
Some small background drain is to be expected but it should not be much. (less than 100 milliamps?)
jeremy