Inconsistent Battery Voltage

[xjokux]

Yay! So far battery stayed consistent. I didn't get a chance to do any runs.

These are the new results I noted done when I got home. Though the stats are lower than before :wacko:


Ignition:
Battery - 12.62
Fuse box - 12.57
Ecmlink - 11.9


Engine on (no load):
Battery - 13.75
Fuse box - 13.7
Ecmlink - 13.1


Engine on (with max load):
Battery - 13.72
Fuse box - 13.74
Ecmlink - 12.2

 

[xjokux]

Alright this morning I had a few voltage drops but not as many as I did before. I'll have re check loose grounds again

Is it likely it could be the alternator getting to hot for wot runs? I've got a 3" stainless steel dump pipe. Once the dollar goes up I'll move the alternator to the back.

 

[bazeng]

Big drop from the ECU to the alternator.
Stock loom?

What are your injectors seeing in voltage?

This could affect your performance.

What i mean by this is, your ECU uses voltage compensaion to control your injector opening times.
If you voltage drops, your injector coils would be getting less power therefor reducing the amount the injectors are open. Your ecu is clever enough to recognise this.

So, if your injectors are seeing 13.7v when on load but your ecu sees 12.2v, your ecu may be compensating for something not required.

I'd try and look at how you could get your ECU to see the same voltage as your alternator output. Most likely related to a bad supply to the ECU or a bad ground connection fom the ECU.

Our cars are getting old. My AMG had the same problem. I fixed it by adding a few additional earth connections from the block to the chassis and cleaning the areas where the existing earth points were. Plus torquing the earth lugs with star washers that peirced the steel when tightened up.

I also installed one of those voltage stabilisers (capacitor) which actullay made a difference!

Good luck!

 

[xjokux]

It's a stock loom from a vr4 loom. Connected to a cb lancer interior loom.

I never really had this issue since I've had the car and it's been years.

I've just check with a meter at the ecu and reads same as ecmlink but lower than from the battery and fuse box.

Thanks. I'll have to check my injectors voltage. So like a 2 in 1 related problem

 

[4piknup]

Baz might be onto something here.
Power is fed to the ecu from the mfi relay. Check your voltage in and out of it.

Injector voltage is hard to check as its a square wave. You need a scope really.