HELP!

[mela!]

Test drove an FTO today. All was well except for one thing.

The car started and idled normally whilst we looked over it. Then got in to drive it. Drove 100m down the road, and as I slowed down to come up to an intersection before down shifting, the car stalled. It wasn't a bunny-hop stall (i.e. not my fault), but as I slowed down, the rpm dropped from about 2000rpm to about 200 and just turned off. The voltmeter also fluctuated a lot. Started it again, sat at the intersection in 1st, and it idled for a few seconds at about 1000rpm then dropped drastically and turned off again. The car continued to do this and by the time we stop-started ourselves back around the block, the engine wouldn't idle for more than about 2-3 seconds before dropping off again.
The car hasn't been touched in 3 months. It was serviced 8000kms ago (the oil is filthy and needs to be changed) but the owner went to pull it out of the garage a few days ago to put some petrol in it and the battery was dead. He jumped the car but did not run it for very long so the battery died again, and he replaced it. Based on the fact that the car was comfortably starting and idling at somewhere around 1000rpm, THEN dropping, and also the situation with the new battery, our best guess was the alternator rather than the idle switch being set too low.

Help/opinions?

The owner has apologised and told us it was running fine before, and will be taking it to get fixed tomorrow hopefully, but what is the general consensus on the situation? Has anyone else had this problem? I know that alternators are a common problem in the FTOs. A friend mentioned it could also be something to do with some brush sensors?
CONFUSED!

[Supplanter]

If the battery has been flat then the ECU would have reset. That means that for the first hour or so it will keep stalling until it learns how to idle properly. This may be why it was stalling.

[mela!]

But it idled fine for the first 10 mins or so before the stereo was on/was being driven?

Just found this:


Usual stuff to go wrong is;

Faulty central locking (easy and cheap to fix - see further down this Q&A section)
Poor brakes, discs can warp easily (either skim them or preferably upgrade them)
Battery not up to the job after a couple of years (change it for a beefier one. Nissan Micra battery is standard on the FTO!!)
Badly behaving idle (the idle control valve or sensor is usually to blame here ... just need to clean them usually)


Should get the idle control switch checked?
It already has a new battery all together so that's not the cause.

[Shane001]

If the battery has been flat then the ECU would have reset. That means that for the first hour or so it will keep stalling until it learns how to idle properly.

I assume disconnecting the battery altogether for a period of time would also reset the ecu, resulting in a need to 'relearn'?

The battery in my racecar is always disconnected (kill switch) every time it's turned off. Can sit for weeks / months without reconnecting. But I never have any problems starting, running or racing it afterwards? Maybe it doesn't need to re learn flat out

Could this be a bit of a myth? (no flames please, genuine question )

[Supplanter]

Any time I have had a flat battery (more than a few ) I have had idling problems in the first hour or so.

[spency]

I had mine off the road for 3 months with gearbox problems and the battery was out. I never had a problem with idling.

[Dras]

If your car is stalling or having real problems idling after an ECU reset, you should adjust the idle control screw on the throttle body. This will allow more air to bypass the butterfly and the stepper motor (controlled by the ECU) won't have to compensate as much.

[mela!]

Yeah of course I'd consider adjusting the idle speed, but why did it idle normally in neutral for 5-10 minutes without the stereo etc running, but then the stalling began AFTER we started driving it? :S

[Dras]

Sorry mela!,

My post was directed more at Supplanter.

Your problem may also be rectified with adjusting the idle speed but it is hard to tell without more info. A car idles higher when the engine is cold and when things like the A/C are running.

I would suggest to diagnose the issue.
Sort out the battery issue so that we can rule out the ECU learning to idle.
Deal with the poor idling for a day and just drive it around so that the ECU learns to idle.
If everything is now good, it was just the idle screw that should be adjusted.
If idle is still poor, it is likely your stepped motor that is causing issues.

Regarding the alternator, your said 'The voltmeter also fluctuated a lot'. This is not enough to go on. If it fluctuates while the revs are over say 1000RPM, then the alternator is likely shot.

[mela!]

Okay. Heard back from the owner who took it into the mechanic. He was told that it was definitely the alternator. Fingers crossed that's right, because I don't feel like driving all the way back down when the car once again isn't drive-able :l
BUT if it was the alternator after all, I've got a new car!
Thanks for the help guys

[silverGPX]

I can turn the idle screw right down to nothing and itll still idle on my GR & GPX. It's low but it still idles. It's the alternator. Probably dropping down to a voltage too low to keep running when you had the stereo plus combined use of brake lights and indicators etc etc.

[mela!]

For the record on this one (a year old, I know), was definitely the alternator and haven't had that same issue since.
Cheers!

[shadowarrior]

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[Bennoz]