Electronic load idle up - 20v 4age

[MWP]

Nope, Microtechs are too stupid to do anything like that.
Remember you talking about an ECU thats 10yrs behind current tech (yes, even new Microtechs are 10yrs behind).
They also dont have the RPM resolution to do it with low RPMs.

Having a manually set high-idle, or using a PWM idle solenoid valve from a different car is the only way to do it.

[oldcorollas]

but if the problem is low voltage, then it is not enough fuel.. i guss you could make idle rich, and then have an air bleed that is triggered by low voltage?

[turbo ke20]

do yourself a favour and toss the microtech in the bin
get yourself a haltech and run the factory idle conrtol motor.
it has 3 wires, centre pin is ignition 12volt and the outer two are idle up and idle down which a dpo output on the haltech will conrtol that perfectly

[pauljones1976]

I'm wondering if it isn't just easier to run a smaller pulley on the alternator to increase the charge and try to keep the microtech over 12.5V?

[oldcorollas]

that would work.
d you have a V belt pulley, with the pulley as two halves? if you put a washer in between, to space the halves out, the belt will sit further in.
depending on the shape, it might work if the belt is still sitting on a flat surface (on the sides)

[thechuckster]

you could also tweak the idle map for timing and spark to 'kick' the engine back up:
- run fuel rich for the load/VR/MAP cells below your desired idle speed
- advance the timing for the high value MAP cells below your desired idle speed
- retard the timing for low value MAP cells below your desired idle speed

the idea being as the motor drops below your target idle speed (regardless of MAP), it gets extra fuel and advances or retards the timing to suit manifold vacuum.

not an ideal solution but can be done where the ISCV isn't helpful.

Another alternative is a simple vacuum-switching solenoid - EFI Camira have a simple idle-up solenoid for the AC - when the compressor kicks in, it also opens a 12V solenoid allowing small amount of air to bypass the throttle.

I used one of the on the 18RTE - worked quite well - and it only requires a simple low-level output (to pull a relay open which then triggers the solenoid) on the ECU.

[pauljones1976]

Charles, whatever happened to the 18RTE?? I remember looking at it once...

Anyway, yes I guess I could muck around and set up some sort of idle controller but the way I see it, that is really only a good solution if you are loading the engine up mechanically at idle (A/C is a great example). But what I'm experiencing is lack of amps/electrical power when accessories drawing power are turned on (lights, thermo etc).

So logically, for me, it would be best to try to solve this by having the alternator generating more current at the same idle speed. I'd say I have two options - spin the alt faster at idle, or upgrade it to one that develops more current at the same spin speed.

I actually installed the 85A EA alt because I thought that would be the case. But unfortunately it hasn't actually made any difference.

Of course, after doing the mod it's hard to just make the decision to buy a better/bigger alt. Modifying the alt that's now on it would be my first choice due to the simplicity of the mod. So I'm going to think in the direction of reducing the size of the pulley on the Alt.

I don't think the pulley is two piece, although I guess it might be possible to make it that way, or I could probably get an engineer to turn it down? Otherwise I might be able to find one from a wrecked car (maybe) but that's going to be very little fun due to needing to get a rattle gun in a tight space.... Does anyone know if you can buy the pulleys as a spare part?

[oldcorollas]

lots of pulleys at wreckers

this looks like 2 piece (cos it necks down in the middle)

[thechuckster]

fwiw: when I got my alternator (was from a ford but only 75A) alternator working correctly, it produced heaps of current at idle. Before stuffing around with pulleys and belts, I'd have a good look at the existing wiring.

MIne looks just like the alt in Stu's pic and you use a standard bosch injector plug (found in great supply on any V6 Commode or Magna engine - the GM engine seems to higher higher temp-rated insulation on the wires) which can be easily removed with wire cutters.

I found that with multiple hatchet jobs on the chassis and engine loom, the charge-light trace from after the light to the Alternator was spliced into another dash circuit causing the alternator to not start charging until revs were well above idle. Solution was to run dedicated trace from the light to the alt (power to the alt light comes via a diode).

Also, when I remote-mounted the battery, I foolishly used the my large 12V distribution post as the 12V sense. After wilbo pointed out the error of this, i added a light gauge wire from the battery directly to the alt and it worked just fine.

The alt will shut down if there is no power at the Alt Light pin so there's no issue in running that wire direct.

I do recall swapping the older 18R alt pulley onto the replacement alternator. This was to change from multi-rib to V-belt. Whether that resulted in a substantial change of pulley ratios I don't know - but from memory they were about the same size... ish.

... oh, 18RTE is languishing outside my storage container - is being parted out ;(

[pauljones1976]

Charles, why does it make a difference where the voltage sense is taken from?

[pauljones1976]

Just found this information on Alternators. Don't know if this is the best place for it, but it is very descriptive:

http://www.alternatorparts.com/FAQ.htm

Charles, when you say you had plenty of power, what were you running at idle? (ie: lights high beam/low beam, radio, thermofan, fuel pumps (x2)??, aftermarket ECU?, high output injectors, blower fans, etc etc)

Did you have the battery in the engine compartment or in the boot?

Just trying to figure out if I have a high current draw compared to others....

[thechuckster]

standard lights, fuel pump (x 1), megasquirt ECU, high-Z injectors, thermo fan (2 then 1). Battery in boot.

interior electricals sometimes included the fan, but i also had the innovate controller plus a dinky-home-made LED gauge for the WB02 and shift lights.

I never much bothered with the radio as I usually had windows down (for the breeze and engine audio) and I'm partly deaf anyway (too many years mixing indie-bands and wearing headphones). If i did have music it would have been ABC Classic FM or Radio National or ripped MP3s of trance/acid-house found on the net.

The voltage sense location has to be the battery. Wilbo explained it to me once - wish I could remember. Is measuring voltage (comparing alt chassis to sense wire and against CHRGE output) not current so wire size not important. Hence the importance of earths and minimal voltage drop from Alt to Battery with the sense wire.

[oldcorollas]

in a basic sense, because the alternator is there to charge the battery.
the battery needs a certain voltage to charge properly, so you may as well get the sense wire directly from there... everything else is powered by the voltage from the battery (albeit a higher voltage when being charged), since the battery is both the storage and distribution point.

if you have poor earths or not so good wires etc, the voltage around the various circuits may differ.

I am a big fan of providing a dedicated sense wire, power wire AND earth wire, from the battery directly to the alternator (earth goes to alternator casing)

people often forget that paint does not conduct electricity ver well, so things like painted alternator casing may not earth very well to the block, and the block may not earth well to the chassis, and the chassis may nto earth well to the battery.... so why not just earth battery to alt directly

[pauljones1976]

Ok, so from what I have read I understand the voltage sense like this:

The alt senses the voltage through the connection (S). It uses this to switch ON. If the voltage at S is low, the alternator switches ON.

To the best of my understanding (and feel free to tell me I'm wrong here as I don't claim to be any sort of expert) the (S) connection does not 'regulate' the current/power being produced by the alternator in any way other than switching it ON.

I'm pretty sure my voltage sense is connected somewhere around the distribution post, not the battery. And while I agree that connecting it directly to the battery would give a more accurate reading, it doesn't appear to affect anything other than turning the Alt ON slightly earlier.

At Idle, my voltage is getting quite low (even at the microtech - as it's reading less than 12V with everything going) so my Alternator is ON. Not having enough voltage is a symptom of not enough power being generated by the Alternator and Battery combined.

I would deduce that not enough power being generated could be caused by the following things:

1) Alternator in poor condition - Idle current low
2) Alternator simply does not have enough current at idle to power all items
3) Ground (-ve) from the alternator through to the (-ve) on the battery is poor, restricting current through the circuit.
4) B+ wire to battery too small and restricting current transfer through the circuit.
5) A short exists in a component somewhere in the electrical system which allows current to bypass the circuit (effectively wasting power and reducing the available potential difference/voltage)

I've checked (3) - using the jumper leads, (4) has been upgraded.

I'm concerned about (1) and I think I need to check the current from the B+ pole on the Alt. Does anyone know what it is 'supposed' to be putting out at idle? (It's the EA 85A alt). What seems odd is that the old alt was the same. But then again, maybe both alt's were worn out?

If the problem is (2), then the smaller pulley could solve it, however it may also just be band-aiding (1) or (5).

(5) seems like a huge problem to track down. But possible I guess. Any ideas of the easiest way to track down a short?? The battery does not go flat 'sitting' around, so I don't think there's a short, but maybe I'm reading too much into that....

[oldcorollas]

ho does the alt know how much power to produce?

ie how does it know how much juice to give to the stator coils at any one time?

i would suggest that the sense wire does a bti more than that.
ie, when the voltage is less than the regulated voltage (say, 14.3 or whatever), then power is fed to the stator coils.
if the battery is fully charged and there is not much current draw from stuff, the voltage reaches 14.3 and then hovers (since power is always being used)
if the battery is low, then the battery will absorb current to charge, adn this will pull down the alt voltage, so the sense wire tells it the voltage is lower than spec, and mre power is fed to the stator coil to increase the current output..

etc

the alt is always "ON" whenever the engine is running. the sense wire tells it if more current is needed, due to it sensing if the voltage is below spec.

if your voltage is 12V with the alt on, either the alt has one of the field diodes farked, or it is just not spinning fast enough due to pulley size

if you follow the Bosch spec sheet somewhere (their aussie site) it shows how little current they produce at idle, and how a small change in idle speed can have a big effect.

B+ wire will reduce max curent, not min current situation.

why haven't you checked the voltag eat the B+ post of alternator yet?
it should be whatever the reg says, which i think is 14.3 for the bosch ones? it will say on the back/side of it.
rather than measure at idle, measure at say, 2000rpm, then let the engine slowly reduce speed until the voltage drops from the reg voltage, to less than that.
remember that speed.
use that speed, divide by the current idle speed, adn thats the % you need to reduce the circumference of your current pulley size..

easiest way to track shorts is to use a multimeter in series, and check the actual current going to each device. if the total is more than each circuit, or seems too much for that particular device, then you have a short of some kind.. but shorts are usually fairly acutely terminal...