Blown88GT
Founding Member
Engine Car stalls when going to a stop with the AC on
- Thread starter michaelgt
- Start date
I'll look at the VSS and the idle control valve again but I already got a new VSS also and the idle control valve is new
That's what I was thinking... is that normal ? is it to low? do I need a new alternator?
Blown88GT
Founding Member
That seems much too high.
Do you have an e-fan? Is it relay controlled?
Is that bad? I have 80 amps at idle... I don't have a sound system just AC headlights and fog lights.. nothing extra
I'll need to recheck when my current draw was at idle, but even with an electric fan I recall it being much lower.
With the ACon is it higher?
With the ACon is it higher?
The VSS does not use voltage for measuring vehicle speed. Voltage output could vary from car to car and with wear and resistance of the connections and wiring.
The computer uses frequency output: as the car speeds up, the VSS output frequency increases. The computer takes the frequency output value it received from the VSS sensor and converts it into MPH. The only way the frequency changes is to make the driveshaft turn faster. Under normal circumstances, that means the car is traveling faster.
In fox body Mustangs a defective VSS will usually set computer trouble code 27 or 28,
Blown88GT
Founding Member
Bad? Is the car going up in flames bad? You have an unaccounted draw of 20A.
Something is seriously wrong. How are you measuring this? DC clamp meter?
I've measured current when Mark VIII fan (using relays) is running with engine on...about 100A. With no eFan, it's about 60A.
GT fog lights are a separate but related issue. You need to get them off the headlamp circuit. I suspect you're headlamp switch is burned & melted. This could be where the excessive current is going. Could also be a bad 3G alternator, if diodes are shorted & not blown. Is the 3G fused?
I don't have any codes maybe I'll just check the wiring for the VSS maybe something there is wrong
https://lmr.com/item/SVE-9902A/Mustang-4-Gauge-Power-Wire-Kit-Premium-W-Noise-Suppression-3 that's what I got with my 3-g 130amps alternator. and no my car is not going on fire it runs great just with the AC on it wants to die. and usually it does so right now I'm not using my AC
And as for the fog lights I already "upgraded" with the relay so my fog lights and headlights are too different circuit maybe I have a bad alternator?
I measured it with the O'Reilly tool it said that it has 80 amps at idle
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There is an idle up to compensate for the load. The ECC gets a signal that the AC is on and initiates slight idle up.
Electrical Load shouldn't change much, just the engagement of the clutch.
Give me a day or so and I can take a load reading at idle with ac on and off. Currently downpouring
Electrical Load shouldn't change much, just the engagement of the clutch.
Give me a day or so and I can take a load reading at idle with ac on and off. Currently downpouring
I took that connector off and put the AC on it didn't turn off but the AC wasn't cold
