Bad idle, need help

[Lorc88]

Hi everyone, 

I have a 2007 Corolla e120 3dr hatchback it's a 1.4 vvt-i

The timing chain had stretched and the car struggled for power. As I couldn't afford to fix it I left the car sat up for a year on the driveway. I've now had the timing chain fixed along with new oil and filters and a water pump. A few days later the alternator gave up the ghost do I had it and the Battery replaced, (new Battery, reconditioned alternator). Now after a few minutes after start up the car idles at 1100rpm and revs up to 1400rpm by itself an then drops off, it does this constantly even after driving it. When I stop at traffic lights I look like a pleb that keeps revving it. 

Anyone else ever experience this sort of thing? Any help would be greatly appreciated 

I've attached a video I took, ignore the Battery light, this is most likely to be a bad earth point as the alternator does charge the battery. 

VID-20180326-WA0020.mp4

[oldcodger]

Hi,

Hard to tell from the video, but from your description its sounds like Learning Mode.

When the Battery has been disconnected /gone flat the ECU looses normal running details and has to start off again.

Until its learnt, you will get those symptoms, usually driving it for 15 -20 mins and things will get back to normal. 

[Lorc88]

20 hours ago, oldcodger said:

Hi,

Hard to tell from the video, but from your description its sounds like Learning Mode.

When the battery has been disconnected /gone flat the ECU looses normal running details and has to start off again.

Until its learnt, you will get those symptoms, usually driving it for 15 -20 mins and things will get back to normal. 

Thanks, I'll try this and let you know how I get on with it 

[Lorc88]

On 03/04/2018 at 4:31 PM, oldcodger said:

Hi,

Hard to tell from the video, but from your description its sounds like Learning Mode.

When the battery has been disconnected /gone flat the ECU looses normal running details and has to start off again.

Until its learnt, you will get those symptoms, usually driving it for 15 -20 mins and things will get back to normal. 

Sadly this is not the case, there's still a fault with the alternator, it's charging the Battery but it's behind the flashing light on the dashboard, perhaps it's because it is a reconditioned unit and not an actual genuine Bosch part, I'm going to get an alternator from a salvage yard and see does it turn off the dash lights 

[oldcodger]

Hi,

You said you have replaced the timing chain, diy or garage ?  then a few days later your alternator and Battery were gone.

At what point did you start getting the poor idle, after the new chain, then how many miles/days before the new Battery /alternator ? 

You say the alternator is charging the Battery, have you checked that with a test meter , first when switched  off,  then running at 1500-2000rpm.

You also say you may have bad earth points, have you cleaned them all up ?  no point checking / changing  things if these are not good.

I once blew the main fuse from the alternator to the battery and ran the old Avensis  for a hundred miles with no alternator charging it, but had no idle or running problems, so why don't you electrically disconnect the alternator and run just on the battery and see if that cures the running problem or not ?

 

 

 

 

[Lorc88]

13 hours ago, oldcodger said:

Hi,

You said you have replaced the timing chain, diy or garage ?  then a few days later your alternator and battery were gone.

At what point did you start getting the poor idle, after the new chain, then how many miles/days before the new battery /alternator ? 

You say the alternator is charging the battery, have you checked that with a test meter , first when switched  off,  then running at 1500-2000rpm.

You also say you may have bad earth points, have you cleaned them all up ?  no point checking / changing  things if these are not good.

I once blew the main fuse from the alternator to the battery and ran the old Avensis  for a hundred miles with no alternator charging it, but had no idle or running problems, so why don't you electrically disconnect the alternator and run just on the battery and see if that cures the running problem or not ?

 

 

 

 

A garage done the chain, the alternator packed up after one week from the chain being done, as I was driving the symptoms were, power steering struggled and the light came on for that (P/S) quickly followed by (ABS) before the car struggled to continue to stay on then Battery light came on and within seconds she stalled and it was game over. Since having the alternator reconditioned the poor idle came about, I fixed this by cleaning the sensor in the air intake and cleaned the butterfly on the carb. I've also replaced a small rubber hose that is near the intake as it was kinked and perished looking. I've cleaned up the Battery terminal wires and the earth under the Battery tray. I've also cleaned up the small wire that connects to the alternator. As the battery light on the dash is flashing its also not fully illuminating its a dull red, the only thing that happens is the lights hav a small pulse in them and the fan for the air inside the car struggles a bit other than that the car runs fine I've driven it 200 kilometres. When I disconnect the electric connector from the alternator the light comes on strong and upon reconnecting it the light stays out for about 5mins before flashing again

[oldcodger]

3 hours ago, Lorc88 said:

A garage done the chain, the alternator packed up after one week from the chain being done, as I was driving the symptoms were, power steering struggled and the light came on for that (P/S) quickly followed by (ABS) before the car struggled to continue to stay on then battery light came on and within seconds she stalled and it was game over. Since having the alternator reconditioned the poor idle came about, I fixed this by cleaning the sensor in the air intake and cleaned the butterfly on the carb. I've also replaced a small rubber hose that is near the intake as it was kinked and perished looking. I've cleaned up the battery terminal wires and the earth under the battery tray. I've also cleaned up the small wire that connects to the alternator. As the battery light on the dash is flashing its also not fully illuminating its a dull red, the only thing that happens is the lights hav a small pulse in them and the fan for the air inside the car struggles a bit other than that the car runs fine I've driven it 200 kilometres. When I disconnect the electric connector from the alternator the light comes on strong and upon reconnecting it the light stays out for about 5mins before flashing again

Hi,

Ok a lot of info there, but an important thing missing.

Is the alternator is charging the Battery correctly. ?

It may be charging in some fashion as you are not reporting the new Battery going flat.

However you do need to first test its outputting the correct voltages as mentioned above.

Also you need to check the alternator for any AC output ( diode failure) and earth connection.

Ytube has lots of good videos on how to do that and you only need a fairly basic test meter.

 

Equally can you take the alternator back to the refurbishers and ask for then to fully test it, they should have much better test equipment.

 

 

[Lorc88]

I've the alternator back twice now, I've been shown it voltage and amp readings they've assured me that it's working perfectly, the Battery when in the car is at its correct voltage, I'll try and change the connector from the car to the alternator to rule that out as being faulty. 

I'll also check the batteries output to make sure it's doing its job. 

Your help and advice is greatly appreciated oldcodger. 

[DeTomato]

I disconnected my Battery at the weekend. I thought it was odd this morning when the Revs were going up and down on standing at a junction. If it's learning mode it goes into, then it looks like it needs to run for a while to get the car up to normal running temperature to settle the Revs down again as with mine, and just as oldcodger said above. The ECU has to re-learn. Hope this helps confirm.

[m456an]

Probably the pcv valve needs cleaning, it worked with my over reving avensis.

[furtula]

Usually once you disconnect the Battery, you need to let car sit while running for 10-15 minutes, so it can remap the ECU.

After that should be fine, there have been numerous topics with people complaining about bad idle after Battery was disconnected and this was usually the fix, or atleast the one you should start troubleshooting with.

[DeTomato]

The thin wire nearest the back of the car Battery is the Air Temp sensor on top of the Air Filter Box.

Did this get damaged or stretched perhaps when dealing with the Battery?

Remove the electrical connector and for a minute to see if it makes any difference to eliminate.

[Lorc88]

I haven't been on for a while, family issues and other personal things going on, after four trips for the alternator I've finally gotten rid of the flashing Battery light on the dash, turned out the repair shop was using Chinese parts, the black plastic on the side of the alternator had no markings the first 3times now it has a few codes and says made in England so no more Battery light, as for the idle issue I ran STP octane and boost restorer in the petrol for a week followed by a slightly more than recommended amount of diptane the following week and now she idles at roughly 850/900 rpm, needless to say I feel I may have had a bad fuel line or blocked injector but all seems well now, also I learned to never ever leave a car sitting up for too long as I needed to replace brake calipers and carriers as they siezed up over time. Happily I can report that my Pride and joy is once again roadworthy and putting a huge smile on my face when I drive it. 

Thanks to everyone who offered me help and advice on this thread I greatly appreciate it, thank you all so very much ☺ 

[oldcodger]

Happy Days !    

[Dave W.]

Glad you're better. When I replaced my alternator, my car was stalling for a while. It got better when I got the professional fuel injector job and a new serpentine belt.