Electronic load idle up - 20v 4age

[pauljones1976]

I tested the voltage at a few points both on the chassis and directly to the engine and found that it did not vary anywhere up the front of the car. It's possible I guess that the alt is not grounding well to the engine block though so I might strap from the alt casing to the chassis and see if that improves things. I have already strapped the engine to the chassis without any improvement.

I decided to push the idle up to 1050rpm to see if it would help. We took her out to the confectionary warehouse in Hendra (as it was pretty much the only place open over easter - and 24hrs at that!) last night. The problem disappeared until the load was increased to fuel pumps, lights, brakes, stereo, and thermofan. Using the blower fan had the same result - problems again.

What I have noticed is that as soon as the voltage drops too low, it's like the microtech loses control and the hunting is as though it's dying and the microtech ups some fuel or something and it tries to increase rpm but then just dies again. The voltage comes back up to 14.4V and over but then it dies again. Even if I turn off a whole bunch of the load (like the lights) it doesn't just 'come good', it'll continue to hunt. However, when it starts to die if I increase the rpm manually with the throttle to a bit over idle rpm for a few seconds it will happily idle away.

I find this quite strange.

With high-beam and blower fan going and the engine under load I am seeing over 16V being generated by the alt. Do I have a problem with my regulator???

[oldcorollas]

I find this quite strange.

With high-beam and blower fan going and the engine under load I am seeing over 16V being generated by the alt. Do I have a problem with my regulator???

it is strange, aybe the microtech goes into some kind of error mode, or trying to operate at the lower voltage causes it to have some glitch.


ahh.. so if you have a good sense wire, and the sense wire is giving the correct voltage..
when you increase electrical load using fans and blower fan and high beam, you are increasing the current through the chassis to the battery.

since the voltage the alternator sees is the potential diference between the case and the sense wire, if the voltage at the case goes up, then the sense voltage appears artificially lower..
ie, if it is happily charging at 14V, but then the case voltage goes to +2V when you turn o high beams/blower fan, thn the voltage "seen" at the sense wire is 12V, so then the reg tries to up it to ge to 14 (which it sees between sense and case) but the overall voltage is 16V? soethig like that.

perhas you could try running ground wires direct to the battery for the high current items, like high bea, blower fan, fuel pump, thermofan etc..

still seems like an earth issue causing the voltage problems.
and the low voltage problems causig the icrotech to go spastic.