Calling all Electrical guru's!
01-14-17, 01:55 PM
#1
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Thread Starter
Calling all Electrical guru's!
So guy's, I have a idle control issue with my microtech ECU where it is essentially a bit basic and does not have some quite key functions. So I want to try and plug something in to create a work around for the main issue I currently have. That is poor idle due to voltage drop when any electrical loads are applied such as fans.
The work around I want is this. I want to wire something in off the back off the alternator or any other 12V wire I guess that reads the voltage, which under normal running will be around 14.2 volts with a good battery. If the voltage temporarily drops down to say 13.8V when a load is switched on I then want this to flip a switch which will allow a 12v supply to be sent to an input on the ECU. Then when the voltage picks back up the switch will flip back and close off the 12v source to the ECU. I hope that makes sense. I think this should also only happen when at idle so I guess that means wiring a microswitch onto the throttle pedal or throttle body that is on/off when the throttle is closed.
Can anyone advise if there is any off the shelf item that will do this or if I need to make something and if so what components am I looking at?
One other thing is ideally I want to be able to adjust the voltage that the switch flips at in order to fine tune the point at which this needs to happen.
Thanks for any help.
Cheers
Lee
The work around I want is this. I want to wire something in off the back off the alternator or any other 12V wire I guess that reads the voltage, which under normal running will be around 14.2 volts with a good battery. If the voltage temporarily drops down to say 13.8V when a load is switched on I then want this to flip a switch which will allow a 12v supply to be sent to an input on the ECU. Then when the voltage picks back up the switch will flip back and close off the 12v source to the ECU. I hope that makes sense. I think this should also only happen when at idle so I guess that means wiring a microswitch onto the throttle pedal or throttle body that is on/off when the throttle is closed.
Can anyone advise if there is any off the shelf item that will do this or if I need to make something and if so what components am I looking at?
One other thing is ideally I want to be able to adjust the voltage that the switch flips at in order to fine tune the point at which this needs to happen.
Thanks for any help.
Cheers
Lee
Last edited by Leeroy_25; 01-14-17 at 02:00 PM.
01-16-17, 11:13 AM
#2
Sounds like you want something similar to a second smaller battery with a relay to power the ECU and some kind of charging circuit like what you would find in an RV for the second battery.
But really the correct solution is to figure out why your voltage is dropping so far. Is your current battery and/or alternator way too small or about to kick the bucket?
But really the correct solution is to figure out why your voltage is dropping so far. Is your current battery and/or alternator way too small or about to kick the bucket?
01-16-17, 03:21 PM
#3
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Thread Starter
I presume alternator is all good as it reads 14.2v normally. battery seems to hold a decent charge considering it is largely being left standing for weeks. It might be a bit weak but it was a good Yuasa unit.
I think voltage drop is normal when load comes on an rpm drops a bit? a lot of people with microtech complain of this issue.
I think voltage drop is normal when load comes on an rpm drops a bit? a lot of people with microtech complain of this issue.
01-17-17, 10:54 AM
#4
you could always try working with what you got. i never did try wiring up the microtech to control idle, but i have heard from several people that it does work, i mean the wiring and options are there so why wouldn't it? the microtech is a bit of a turd but it does have a few outputs, so may as well use what skimpy stuff they did actually give us.
from the protege boys on another forum:
from the protege boys on another forum:
And how did you accomplish this?
Info please.
One of the outputs is a stepper motor/PWM output.
Given that the outputs supply a ground, i wired this to the ground for the IAC solenoid
then it was a case of tuning it using AuxAir_Min, AuxAir_Max, and the other settings (target RPM, etc)
In order to cut out some noise, the ground and power were bridged with a diode.
I then wired one of the inputs to the airconditioner compressor, so that when it activated i could bump the idle up with InpAir_Add.
its nowhere near as good as the stock IAC...but it works none the less.
Info please.
One of the outputs is a stepper motor/PWM output.
Given that the outputs supply a ground, i wired this to the ground for the IAC solenoid
then it was a case of tuning it using AuxAir_Min, AuxAir_Max, and the other settings (target RPM, etc)
In order to cut out some noise, the ground and power were bridged with a diode.
I then wired one of the inputs to the airconditioner compressor, so that when it activated i could bump the idle up with InpAir_Add.
its nowhere near as good as the stock IAC...but it works none the less.
Last edited by RotaryEvolution; 01-17-17 at 10:57 AM.
01-17-17, 03:30 PM
#5
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Thread Starter
Yes.. I plan to get this working too.. I have it wired up and plugged in but I cannot get any start point settings to put in the values or work out how to turn it on?! manual is super vague.. I posted in the microtech forum but no takers!?
01-19-17, 08:20 AM
#6
Hello Leroy, what you are asking makes sense. You basically want a volt meter/sensor to provide a signal when appropriate, to up the idle.
I get a 50 rpm drop with a big electrical load. I just checked that the other day. I don't think 50 RPM would kill a motor, although, I have a stock port. Maybe you are on the jagged edge of tune in which case my comparison doesn't apply.
The simple solution is find out why the electrical load saps the motor so much. If you have a simple voltmeter, you should find at what point the motor suffers from the load. 13.8-14.3 is usually normal low regulated output.
Can you check your battery to see if a cell is dead? Do you possibly have weak ground? The weak ground would make the alternator/regulator struggle to get the output at the proper level.
Back to the solution, you need a relay for sure. The load sensing "chip" would have to be the trigger, but off hand, I am not aware of one. I would think it already exists for automotive application. Maybe a second regulator may work as it is doing exactly what you want. It senses voltage, and at the proper voltage point, shorts A to F. Hmmm, maybe a second regulator wired in for your purpose may work. You would wire one side of A/F to ground, and the other side would trigger the relay, which would send the signal to the ECU.
This may work...............but may be overly complex.......maybe the existing voltage regulator that is already in place can do the trick, assuming your present charging system is good, find the wire that puts your alternator into "full field". It should be -.............tap a wire off this wire and use it to trigger the relay. Relays can be wired a multitude of ways, positive or negative trigger easily. I am not sure if a diode will work on the negative wire. If it would, adding one in would be great to keep the charging circuit from getting outside "noise"........
I have not tried any of this, but it will give you a basis to start poking around. Your original request is not all that "out there". Late model FI cars do exactly what you want. New cars have a tremendous electrical load ( compared to our RX's), and this is done to maintain idle quality and temperature stability.
I know I didn't give you a direct answer or a schematic, but you are on the right trail. I do say check your charging system fully first though.......
Good luck
Rich
I get a 50 rpm drop with a big electrical load. I just checked that the other day. I don't think 50 RPM would kill a motor, although, I have a stock port. Maybe you are on the jagged edge of tune in which case my comparison doesn't apply.
The simple solution is find out why the electrical load saps the motor so much. If you have a simple voltmeter, you should find at what point the motor suffers from the load. 13.8-14.3 is usually normal low regulated output.
Can you check your battery to see if a cell is dead? Do you possibly have weak ground? The weak ground would make the alternator/regulator struggle to get the output at the proper level.
Back to the solution, you need a relay for sure. The load sensing "chip" would have to be the trigger, but off hand, I am not aware of one. I would think it already exists for automotive application. Maybe a second regulator may work as it is doing exactly what you want. It senses voltage, and at the proper voltage point, shorts A to F. Hmmm, maybe a second regulator wired in for your purpose may work. You would wire one side of A/F to ground, and the other side would trigger the relay, which would send the signal to the ECU.
This may work...............but may be overly complex.......maybe the existing voltage regulator that is already in place can do the trick, assuming your present charging system is good, find the wire that puts your alternator into "full field". It should be -.............tap a wire off this wire and use it to trigger the relay. Relays can be wired a multitude of ways, positive or negative trigger easily. I am not sure if a diode will work on the negative wire. If it would, adding one in would be great to keep the charging circuit from getting outside "noise"........
I have not tried any of this, but it will give you a basis to start poking around. Your original request is not all that "out there". Late model FI cars do exactly what you want. New cars have a tremendous electrical load ( compared to our RX's), and this is done to maintain idle quality and temperature stability.
I know I didn't give you a direct answer or a schematic, but you are on the right trail. I do say check your charging system fully first though.......
Good luck
Rich
01-19-17, 12:05 PM
#7
Don't you have any spare GPIOs available? Many OEM and aftermarket ECUs will do an idle up under heavy electrical load by simple logic trigger on a load input. Just diode OR any major electrical load (e-fan, headlights, etc) to a spare input and make it happen. No need to complicate this with a closed-loop system using voltage sensing, IMO.
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01-19-17, 03:01 PM
#8
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Thread Starter
I have found a charging system that works in reverse but I believe I can switch the output with a relay to get it to do what I want so I am looking into this right now.
The RPM drops a little but not a little. I would guess maybe 50rpm. The voltage drops a good 0.5v for a second or two when the load comes on and then normalises again if the engine stays running. which can be done by making it richer or course. but too rich for normal running. I believe the issue is the sap in voltage slows the injectors too much or reduces their pulse so they don't inject enough fuel and the ECU does not have voltage compensation built in like a lot of ecu's do.. or certainly not that works with the aftermarket injectors. It dies because the engine leans off too much as the voltage drops and then it cannot catch itself in time when it starts to come back up.
So if anyone thinks my voltage drop is too much I can look into battery condition and ground. Battery is in the boot with all new wiring and the ground direct onto the suspension turret/rear strut brace? How can I check the battery? Do I need to get it drop tested? I can probably take it somewhere and get that done. I wouldn't rule that out. It is a quality battery but I think it has had a hard life before! What voltage should it read just standing on it's own? or after a day maybe? Whether that fixes it or not I quite like the idea of an idle up control unit that will detect any load. and it will be fully adjustable for operational voltages and switching delays etc. I would say connecting multiple loads separately to the ECU with diodes is complicated compared to taking a 12v ignition live and wiring that to a box to detect voltage drop for any reason. I assume a 12v igntion live will read as 14.2 volts or what ever the alternator is putting out? or do I need to get direct on the alternator output to see that? or what ever wire the ECU is reading it's voltage from anyway.
The RPM drops a little but not a little. I would guess maybe 50rpm. The voltage drops a good 0.5v for a second or two when the load comes on and then normalises again if the engine stays running. which can be done by making it richer or course. but too rich for normal running. I believe the issue is the sap in voltage slows the injectors too much or reduces their pulse so they don't inject enough fuel and the ECU does not have voltage compensation built in like a lot of ecu's do.. or certainly not that works with the aftermarket injectors. It dies because the engine leans off too much as the voltage drops and then it cannot catch itself in time when it starts to come back up.
So if anyone thinks my voltage drop is too much I can look into battery condition and ground. Battery is in the boot with all new wiring and the ground direct onto the suspension turret/rear strut brace? How can I check the battery? Do I need to get it drop tested? I can probably take it somewhere and get that done. I wouldn't rule that out. It is a quality battery but I think it has had a hard life before! What voltage should it read just standing on it's own? or after a day maybe? Whether that fixes it or not I quite like the idea of an idle up control unit that will detect any load. and it will be fully adjustable for operational voltages and switching delays etc. I would say connecting multiple loads separately to the ECU with diodes is complicated compared to taking a 12v ignition live and wiring that to a box to detect voltage drop for any reason. I assume a 12v igntion live will read as 14.2 volts or what ever the alternator is putting out? or do I need to get direct on the alternator output to see that? or what ever wire the ECU is reading it's voltage from anyway.
01-21-17, 12:55 AM
#9
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I am just wondering if the ECU doesn't compensate for some voltage variation.
I can see a volt or so and the Ecu stays on track But after the Voltage drops to say 10 the thing would and should shut down?
Am I wrong to say that your ECU should allow some voltage variation without changing the parameters of the setup?
Really a half a volt should not matter.
I can see a volt or so and the Ecu stays on track But after the Voltage drops to say 10 the thing would and should shut down?
Am I wrong to say that your ECU should allow some voltage variation without changing the parameters of the setup?
Really a half a volt should not matter.
01-21-17, 02:26 AM
#10
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Thread Starter
As far as I can find out Microtech does not have voltage compensation built in or at least not very good if it has. Quite a few people have had thread on idle issue due to loads coming on with microtech so it is quite a normal problem with these ecu's I think. Various work around compromise AFR or idle speed to get over it. But I want to try something a bit different and make use of the ECU input so it doesn't just puck up the one load buy any.
01-21-17, 08:28 AM
#11
Hello again Leroy, are you certain that the voltage drop is affecting injector dwell? Do you have an AFR meter of some sort? Generally, these systems are able to work in a fairly wide voltage variance.
Yes, the current ecu should hold the idle steady, as it has the ability to sense RPM drop, and adjust. Yours isn't reacting this way.
The battery when fully charged should read over 12.8 volts. That is the reading directly across the battery terminals with the key off and motor off. Then when running, it should exceed 13v to a max of 14.5 or so. If it goes higher than 14.5 for more than a second or so ( the time it takes the regulator to recognize the overcharge condition and react) then you could have a regulator problem, but you are not overcharging at present.
I am not sure of the construction of your battery, but a hydrometer is good for understanding the condition of each cell in the battery. If you have one weak cell, but 5 strong ones ( usually 6 cells total in a 12v battery) you will have charging issues. Batteries usually slowly degrade. The cells become sulfided and can start to short internally. I have found that most quality batteries can last 3 years if maintained properly. If they go dead, then are recharged often, this will shorten the life of the battery. At my company ( car service) we change out our batteries each May. Cheap insurance. If you are keeping this car, investing in a known good battery makes sense. You know it is good then and should last for years if taken care of.
The remote battery creates additional resistance, and voltage drop in the car. With a remote battery, everything in the system is that much more critical. You can use a meter ( like a VOM available at HF for free sometimes) to check the resistance or ohms. Ideally, there will be close to no resistance, but of course, the wire and connections will create some. The ground path is HUGE here. You said the battery ground or negative was wired to a suspension component. Keep in mind, you are using the car's chassis as a "wire" to connect the battery and alternator and all accessories. You should ohm out both positive and negative cables.
An easy test is to check the battery voltage with the negative cable disconnected ( you can leave the pos. in place). Write the voltage number down, then connect the negative cable, and start the car and see what the voltage reads at various RPM ranges. The voltage should increase slightly when the revs go up. Then turn on accessories one at a time and read the voltage. Use the headlights and or the heater blower, as these create significant draw.
Record these numbers ( and at what conditions) and post them up. Someone here will help you determine what is going on with your charging system.
Good luck
Rich
Yes, the current ecu should hold the idle steady, as it has the ability to sense RPM drop, and adjust. Yours isn't reacting this way.
The battery when fully charged should read over 12.8 volts. That is the reading directly across the battery terminals with the key off and motor off. Then when running, it should exceed 13v to a max of 14.5 or so. If it goes higher than 14.5 for more than a second or so ( the time it takes the regulator to recognize the overcharge condition and react) then you could have a regulator problem, but you are not overcharging at present.
I am not sure of the construction of your battery, but a hydrometer is good for understanding the condition of each cell in the battery. If you have one weak cell, but 5 strong ones ( usually 6 cells total in a 12v battery) you will have charging issues. Batteries usually slowly degrade. The cells become sulfided and can start to short internally. I have found that most quality batteries can last 3 years if maintained properly. If they go dead, then are recharged often, this will shorten the life of the battery. At my company ( car service) we change out our batteries each May. Cheap insurance. If you are keeping this car, investing in a known good battery makes sense. You know it is good then and should last for years if taken care of.
The remote battery creates additional resistance, and voltage drop in the car. With a remote battery, everything in the system is that much more critical. You can use a meter ( like a VOM available at HF for free sometimes) to check the resistance or ohms. Ideally, there will be close to no resistance, but of course, the wire and connections will create some. The ground path is HUGE here. You said the battery ground or negative was wired to a suspension component. Keep in mind, you are using the car's chassis as a "wire" to connect the battery and alternator and all accessories. You should ohm out both positive and negative cables.
An easy test is to check the battery voltage with the negative cable disconnected ( you can leave the pos. in place). Write the voltage number down, then connect the negative cable, and start the car and see what the voltage reads at various RPM ranges. The voltage should increase slightly when the revs go up. Then turn on accessories one at a time and read the voltage. Use the headlights and or the heater blower, as these create significant draw.
Record these numbers ( and at what conditions) and post them up. Someone here will help you determine what is going on with your charging system.
Good luck
Rich
01-21-17, 10:34 AM
#12
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This is not really too hard to do with your choice of microcontroller.
Copy the Megasquirt coil RPM input circuit (optocoupler) and feed it to an Arduino (even an ATTINY can handle this in an 8 pin package). The chip just runs a PID loop, with the output being a MOSFET PWM'ing the idle valve. Simple idle controller. You just need to tune the PID loop. Maybe also connect an analog input of said chip to the ECT output so you can have a high idle when cold.
But why?
Switch to an ECU designed after 1995 that has all this included.
Copy the Megasquirt coil RPM input circuit (optocoupler) and feed it to an Arduino (even an ATTINY can handle this in an 8 pin package). The chip just runs a PID loop, with the output being a MOSFET PWM'ing the idle valve. Simple idle controller. You just need to tune the PID loop. Maybe also connect an analog input of said chip to the ECT output so you can have a high idle when cold.
But why?
Switch to an ECU designed after 1995 that has all this included.
01-21-17, 05:58 PM
#13
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Thread Starter
I have not long wired this ECU so it is what I am stuck with for now.. I thought this idea was quite simple and low cost and making use of the input functions on the ecu... If I can get the IAC working as well with the microtech then that should have all bases covered. More than anything I want to know if my hair brained idea will work now!
I took the battery to shop today to get it load tested and it has been sat unused and uncharged for a couple of weeks no.. Read around 12.2 volts or so and when loaded dropped just below 12.. and then pull right back up as soon as the load was shut off.. So I guess the battery is good. I will check for resistance on my wires and make double sure my ground is clean. Still no one has said if my voltage drop is normal or not anyway!?
From memory.. when it idles it sits at just over 14.1v with a 950rpm idle.. A light rev and it goes up to 14.3 I think.#When a load is switched on it drops to about 13.7-13.8.
I think my injector data said for a similar voltage reading they would require about 10% correction. So if the ECU has little or no voltage compensation 10% is quite a bit on an 875cc injector. Will see what it is like after a proper tune in matrix mode in the next couple of weeks. and try and figure out the settings for the IAC.
I took the battery to shop today to get it load tested and it has been sat unused and uncharged for a couple of weeks no.. Read around 12.2 volts or so and when loaded dropped just below 12.. and then pull right back up as soon as the load was shut off.. So I guess the battery is good. I will check for resistance on my wires and make double sure my ground is clean. Still no one has said if my voltage drop is normal or not anyway!?
From memory.. when it idles it sits at just over 14.1v with a 950rpm idle.. A light rev and it goes up to 14.3 I think.#When a load is switched on it drops to about 13.7-13.8.
I think my injector data said for a similar voltage reading they would require about 10% correction. So if the ECU has little or no voltage compensation 10% is quite a bit on an 875cc injector. Will see what it is like after a proper tune in matrix mode in the next couple of weeks. and try and figure out the settings for the IAC.