Aftermarket Engine Management - Burning Questions

[SilverGhost]

Hi All,

After researching as much as I can online these is still some questions surrounding aftermarket ECU's that I need clarification with. If this has been covered elsewhere please let me know.

My questions are:

1. Can your old ECU be completely removed? or does it need to remain to run guages, ABS system etc?

2. Does an a/m ECU run all its own sensors, does it use all existing sensors, or a combination of the 2?

Further to this, if it utilises existing sensors, would it be recommended to replace them all (garbage in garbage out etc)

3. I know you can convert an AFM metered motor to MAP or even hot wire if you wanted to, but in terms of ignition, can you ditch a distributor setup for coil packs and/or remove your igniter setup (not sure if igniters are used with coil packs)

4. Can a/m ECU's provide outputs for guages like a/f ratio, oil pressure?

5. In the course of upgrading to an a/m ECU would you completely remove your old engine loom in favour of a new loom?

6. Whats the final word on legality. Do they need to be engineered? Can they be engineered? (im from NSW)

cheers!

[SilverGhost]

If these questions need make and model, im referring to an ST185 GT4 with 2nd Gen 3SGTE.

[CrUZida]

1) Depends on car, what have you got? In new car cases you may need to leave the stock ecu there to control a few things, but most of the time it goes.

2) Depends on the ecu, most will retain all/nearly all stock sensors.

3) Depends on the ecu again. 99% of them use MAP, so you ditched the AFM. Most will need external ignitors. A lot of factory ignitors don't work with most aftermarket ecu's

4) Most can't, but there will be a couple that can (expensive ones)

5) No need to, but you can if you like

6) Check the link in my sig

[mullett]

Here's what I understand of it:

My questions are:

1. Can your old ECU be completely removed? or does it need to remain to run guages, ABS system etc? yes, in the case of older cars (like yours) newer cars which rely heavily on the factory ECU need to be piggybacked or re-tuned.

2. Does an a/m ECU run all its own sensors, does it use all existing sensors, or a combination of the 2? Generally they use the existing sensors, most people don't replace them, but I guess you could if you wanted to. Furthermore, some sensors won't be used (like my knock sensor)

Further to this, if it utilises existing sensors, would it be recommended to replace them all (garbage in garbage out etc)

3. I know you can convert an AFM metered motor to MAP or even hot wire if you wanted to, but in terms of ignition, can you ditch a distributor setup for coil packs and/or remove your igniter setup (not sure if igniters are used with coil packs)
yes, you can ditch the dizzy if you get an ECU with ignitors to suit the cylinder count of your car and get coilpacks. EMS stinger has an add-on module for coilpacks, and some Microtechs can be ordered with them.

4. Can a/m ECU's provide outputs for guages like a/f ratio, oil pressure?
There will generally be a few outputs from the ECU, depending on what you get, but usually your gauges will keep working, as they attach to the body loom (which isn't affected). If you want aftermarket gauges, they usually wire in to the sensor/have their own.

5. In the course of upgrading to an a/m ECU would you completely remove your old engine loom in favour of a new loom? It's the ideal way to do it; get new plugs etc and make a whole new loom, but it's easiest and quickest to cut the old ECU at the plug and wire the new loom in there.

6. Whats the final word on legality. Do they need to be engineered? Can they be engineered? (im from NSW) Can't answer that sorry


Hope that helps

RM.

[LeeRoy]

1. Can your old ECU be completely removed? or does it need to remain to run guages, ABS system etc?

Depending on the computer some will require it to stay and others will run without it. If you go a full engine management computer that will be all that is needed engine wise whereas a piggy back style runs off the existing computer pretty much.
As far as ABS goes that has it's own computer i'm pretty much and the same goes for Auto transmissions

2. Does an a/m ECU run all its own sensors, does it use all existing sensors, or a combination of the 2?

Further to this, if it utilises existing sensors, would it be recommended to replace them all (garbage in garbage out etc)

Mix of both. On YOUR engine the manufacturer has picked the right sensors for it to operate as in they are in the right band of readings and can communicate to the computer. Depending on the specific computer you should be able to run most of the sensors if not all of them. However, your computer may come with sensors that need to be used or you may opt for different sensors ie ditch an AFM and go for a MAP sensor.

3. I know you can convert an AFM metered motor to MAP or even hot wire if you wanted to, but in terms of ignition, can you ditch a distributor setup for coil packs and/or remove your igniter setup (not sure if igniters are used with coil packs)

Yes you can ditch a dizzy for electronic ign but coils need ignitors to run. Some coils like that of the LS1 commodore donk have in built ignitors to the coils. As far as this goes depending on your computer will also determine what you can and can't do as a bottom end entry computer may not be able to run this and a higher level computer will.

4. Can a/m ECU's provide outputs for guages like a/f ratio, oil pressure?

Yes.

5. In the course of upgrading to an a/m ECU would you completely remove your old engine loom in favour of a new loom?

That depends what computer you use. If you go piggy back/reprogrammed then the standard loom would be used, whereas a completely aftermarket computer will come with it's own loom to which you hook up to a combo of old and new sensors.

6. Whats the final word on legality. Do they need to be engineered? Can they be engineered? (im from NSW)

cheers!

They should be engineered but you will find that most aren't due to the cost and difficulty of getting them passed. There is a fair amount of dyno time and costs getting tests done before it passes and most people avoid the hassle. Simply put, it should be engineered and can be engineered.

- LeeRoy

[mullett]

That was cool: 3 people with similar posts in a few minutes

RM.

[LeeRoy]

Yeh that took me ages , i'm like sweet i'll get in first post and then i hit post and was all

- LeeRoy

[CrUZida]

Just FYI, my post is on the basis that you are talking about a full standalone aftermarket ecu, and not a piggyback/interceptor ecu (which I don't class as aftermarket ecu's)

[SilverGhost]

thanks for all the input guys!

Shit another Q. are there any ECU's that have integrated boost control, or is it just simpler to setup an external EBC?

As far as i see it all the hardware on my car is 16 y/o now, the wiring, sensors (bar ones ive replaced) dizzy etc. so I would want to replace as much as possible. IMO its like rebuilding a motor with an old HG, its bound to be the weak point.

In my case im looking for an ECU that has the following features

-take complete control of engine management (no piggyback)
-has all new engine loom
-Remove the dizzy in favour of coil packs
-Remove AFM in favour of MAP
-not too worried about a handset, (its a 'nice to have') but definitely one that has an output for a lappy and accompanying software
- Has enough outputs to control things like T-VIS (im assuming most ppl dont worry about EGR when they go aftermarket)
- An output for a/f meter (off a wideband sensor perferrably) and water injection

According to your replies things like coild packs and igniters etc come with certain ECU's

Is this within the realms of possibility? or would all these options only apply to super uber elite dori dori ECU's?

[CrUZida]

Almost every ecu will do what you are asking.

The only thing I'm not sure about is the output for a/f meter.
Most ecu's will not have this output, and you will need to buy a unit to convert to sensor output to a normal AFR.

[CrUZida]

Also the sensors on the engine (TPS, water temp, crank/cam angle) RARELY fail.

Replacing those is only going to cost mucho $$.

[SilverGhost]

Almost every ecu will do what you are asking.

The only thing I'm not sure about is the output for a/f meter.
Most ecu's will not have this output, and you will need to buy a unit to convert to sensor output to a normal AFR.

If I was to buy an a/f guage, i assume there are kits out there that have a matched sensor/sender to a guage? otherwise how else would you be certain the readings are accurate.

I might have answered why most ECU's dont provide that output. Who knows what brand of guage people would want to hook up to it.

[mullett]

I agree, new sensors are $$$y, and old ones are amazingly reliable. As for output to AFR meter, I don't think you've got a whole lot of chance, because the reading is only as good as the sensor, and factory 02 sensors are pretty lame. If you want to go extreme, get something like a Bosch 4 wire sensor. Someone correct me if I'm wrong, but most aftermarket ECUs don't take a reading from the 02 sensor at all do they? Having a look at the diagram for my EMS DualSport, it's got input for a Bosch wideband sensor, but no mention of a pickup for a standard 02 sensor...So you're looking at a 4 wire anyway, might as well wire it straight to the Lambda meter. If you want a rough idea using the stock sensor, get a JayCar AFR kit...designed to work with a standard sensor...

RM.

[CrUZida]

Most people use either the LM1 (or LC1) or the TechEdge WBO2 (http://www.wbo2.com) ones.

Prepare for ~$400+

Microtech can display straight from the sensor, but you have to buy the sensor (few hundred) have the ecu programmed to do it ($50 I think) and then use the Microtech Dash to display without a laptop ($500)

[SilverGhost]

I agree, new sensors are $$$y, and old ones are amazingly reliable. As for output to AFR meter, I don't think you've got a whole lot of chance, because the reading is only as good as the sensor, and factory 02 sensors are pretty lame. If you want to go extreme, get something like a Bosch 4 wire sensor. Someone correct me if I'm wrong, but most aftermarket ECUs don't take a reading from the 02 sensor at all do they? Having a look at the diagram for my EMS DualSport, it's got input for a Bosch wideband sensor, but no mention of a pickup for a standard 02 sensor...So you're looking at a 4 wire anyway, might as well wire it straight to the Lambda meter. If you want a rough idea using the stock sensor, get a JayCar AFR kit...designed to work with a standard sensor...

RM.

isnt a lmabda meter and o2 sensor the same thing? I would have thought all a/m ECU's utilise a/f readings from a tuning point of view, in addition you said earlier that they most likely wont utilise a knock sensor either? seems a bit pedestrian for a unit that is supposed to be superior to my old l-jetronic system, or have i missed the point?