Weak idle

[Harry]

My expy. Started having a weak idle. The RPM will go below "1" and the battery light goes off. What can it be? Please help.

 

[bigdogchrisl]

That could be a lot, I'm sorry. Could be fuel pump, clogged fuel filter, clogged injectors, weak spark, battery/alternator dying...
When does it happen?
BTW - Battery light should ALWAYS be off, only on if it dying or dead. Does the gauge show charging when it's running?
Also, my older cars typically idled at 750/800 only 12-1500 at initial start.


Sent from my SM-G965U using Tapatalk

 

[Harry]

That could be a lot, I'm sorry. Could be fuel pump, clogged fuel filter, clogged injectors, weak spark, battery/alternator dying...
When does it happen?
BTW - Battery light should ALWAYS be off, only on if it dying or dead. Does the gauge show charging when it's running?
Also, my older cars typically idled at 750/800 only 12-1500 at initial start.


Sent from my SM-G965U using Tapatalk

It has been happening in the morning on my way to work. I let the car warm first but then this problem occurs.

 

[Harry]

It does say it's charging. The battery gauge doesn't move

 

[bigdogchrisl]

So, it doesn't sound like battery/alternator... is battery light on or off? It should illuminate when you start the truck, and turn off once its started. Initial rpm"s can creep up to 12-1500 but drop under 1000 once its warmed up a little.
If the above is what your seeing, its just working.
If you have the AC set to run. You hear a click - THEN there is this dip, that's the AC Compressor cycling on and attempting to function. Does the AC work (if this is the pattern)?

If also recommend checking for vacuum leaks...


Sent from my SM-G965U using Tapatalk

 

[99WhiteC5Coupe]

As always; year, make, model and engine would be helpful.

It sounds like a bad battery with a dirty throttle body bore.

 

[Harry]

So, it doesn't sound like battery/alternator... is battery light on or off? It should illuminate when you start the truck, and turn off once its started. Initial rpm"s can creep up to 12-1500 but drop under 1000 once its warmed up a little.
If the above is what your seeing, its just working.
If you have the AC set to run. You hear a click - THEN there is this dip, that's the AC Compressor cycling on and attempting to function. Does the AC work (if this is the pattern)?

If also recommend checking for vacuum leaks...


Sent from my SM-G965U using Tapatalk

Well it has normal RPM idle then it fluctuates down below 1000 and up. When it drops, the battery light comes on.

 

[Harry]

As always; year, make, model and engine would be helpful.

It sounds like a bad battery with a dirty throttle body bore.

Sorry.
2003 Eddie Bauer expedition

The battery light comes on when RPM drops. Sounds like it's about die out

 

[bigdogchrisl]

So, if the RPM's are dropping so low that the alternator output isn't sufficient to charge the battery - you would get the light.
Honestly I'm back to vacuum leak

Sent from my SM-G965U using Tapatalk

 

[bigdogchrisl]

You aren't getting a check engine light, are you?

Sent from my SM-G965U using Tapatalk