2007 aygo dies when alternator is connected

[niceone]

Hello. Sometimes it starts and I have to hold down the throttle to keep it running, but usually it starts and instantly dies. Tried replacing alternator and same thing happens. Only when the big alternator cable is disconnected will the car start right up and run. Both alternators were charging 14.1 V.

[flash22]

Have you checked the other items driven by the belt, a/c pump if fitted is a common cause

connect the alternator but slacken the belt off, 1/4 twist of the belt in the longest part is about right

 

sounds like it has a bad ground, possibly you missed it when putting the engine in - use a jumper cable between the engine block and body to act as a ground

 

 

[niceone]

13 minutes ago, flash22 said:

Have you checked the other items driven by the belt, a/c pump if fitted is a common cause

connect the alternator but slacken the belt off, 1/4 twist of the belt in the longest part is about right

 

sounds like it has a bad ground, possibly you missed it when putting the engine in - use a jumper cable between the engine block and body to ack as a ground

 

Theres no ac, everything spins fine. The ground is ok also.

[flash22]

is it a 2 or 3 pin alternator or does it just have 2 posts

[niceone]

4 minutes ago, flash22 said:

is it a 2 or 3 pin alternator or does it just have 2 posts

Just 2. I found the same issue in this forum but there werent no answer. https://community.cartalk.com/t/engine-dies-when-the-alternator-is-connected/168073

[flash22]

Are the posts the same size ? Make sure you have it wired correctly

[niceone]

4 minutes ago, flash22 said:

Are the posts the same size ? Make sure you have it wired correctly

Ones is bigger

[niceone]

8 minutes ago, flash22 said:

Are the posts the same size ? Make sure you have it wired correctly

What is this thing, maby this can cause my problem?

[flash22]

No, not really that is the vent valve

[flash22]

So it runs fine with the alternator disconnected

[niceone]

16 minutes ago, flash22 said:

So it runs fine with the alternator disconnected

Yeah

[flash22]

Disconnect the d+ (smaller) wire from the alternator, tape up the end

really seems like a bad ground put a jumper cable between the alternator bracket and the body or Battery negative

[niceone]

1 hour ago, flash22 said:

Disconnect the d+ (smaller) wire from the alternator, tape up the end

really seems like a bad ground put a jumper cable between the alternator bracket and the body or battery negative

No benefit. One thing I can say is that the cylinders look wet when looking at them, maby thats normal.

[niceone]

2 hours ago, flash22 said:

Disconnect the d+ (smaller) wire from the alternator, tape up the end

really seems like a bad ground put a jumper cable between the alternator bracket and the body or battery negative

Should there be any voltage or anything on the smaller wire, since it has nothing, neutral wire.

[flash22]

do you get a Battery light on the dash, ignition on

 

 

 

 

 

 

 

[niceone]

1 minute ago, flash22 said:

do you get a battery light on the dash, ignition on

 

 

 

 

 

 

 

Yes

[flash22]

Check the red cables from the Battery and the connections on the fuse box

[flash22]

The only thing i can see that may cause an issue is the starter motor what is just 2 wires, 1 from the Battery and the other to the solenoid - it's the only item that would pull enough current to cause the alternator to load heavily

did you remove the fuse box for any reason ??

Will the car start with the fan/AUX belt removed ? If so, see if the starter is getting very hot

[niceone]

50 minutes ago, flash22 said:

The only thing i can see that may cause an issue is the starter motor what is just 2 wires, 1 from the battery and the other to the solenoid - it's the only item that would pull enough current to cause the alternator to load heavily

did you remove the fuse box for any reason ??

Will the car start with the fan/AUX belt removed ? If so, see if the starter is getting very hot

The alternator spind quite freely and I tried two now so it shouldnt be an issue. The water pump, the crank also spin easilly. I have found a zener diode on the combination meter that shows 0.1V both ways, maby this is the cause, since this may be the diode that connects to the small wire of the alternator, but I cant tell, just know there is one.The one next to d13.

[niceone]

53 minutes ago, flash22 said:

The only thing i can see that may cause an issue is the starter motor what is just 2 wires, 1 from the battery and the other to the solenoid - it's the only item that would pull enough current to cause the alternator to load heavily

did you remove the fuse box for any reason ??

Will the car start with the fan/AUX belt removed ? If so, see if the starter is getting very hot

Its also not the starter motor because when I get it started sometimes I can rev it and keep it alive, but dies without throttle instantly, while the starter aint working. I even reconnected the alternator while it was running and it died because of that.

[Derek.w]

Regarding the starter motor,

Do you see any signs of a ring of fire around the comutator thats the part the carbon brushes delivers the power to the rotor?.

[Derek.w]

thats when you run the starter motor

[flash22]

The only reason, an alternator would load an engine is if the alternator was heavily loaded or starting to seize, revving the car would overcome the resistance

the starter is the only item large current draw item directly on the Battery, unless you have the electric heater

it's not a dead short as that should blow a fuse

Will it start without the fan belt ?

 

The only other reason's is it's down on compression, or it's not idling up under load

[niceone]

1 hour ago, flash22 said:

The only reason, an alternator would load an engine is if the alternator was heavily loaded or starting to seize, revving the car would overcome the resistance

the starter is the only item large current draw item directly on the battery, unless you have the electric heater

it's not a dead short as that should blow a fuse

Will it start without the fan belt ?

 

The only other reason's is it's down on compression, or it's not idling up under load

Maby I could just meassure the current draw? It would run without the belt l since it wouldnt make the alternator do anything.

[niceone]

The diode was good.