Standalone ECU setup, few open questions

Hello,

I am planning to setup a standalone ECU (MaxxECU) with jumper harness, so i don't need to destroy the original ECU harness.
I can try to make this write up so that it is useful with many other standalone systems as well, as there are constantly coming new standalone ECU options for this kind of setup.
As far as i know the inputs and outputs that are needed for this are following;
Outputs;
- 6 Injector outputs
- 3 Coil outputs (I think the Coil Dwell time should be 3ms. Correct this if it isn't right)
- Radiator fan switch
- Idle stepper motor this apparently needs 4 outputs.
- Fuel pump relay
- Wastegate solenoid PWM controlled

Inputs;
- TPS
- IAT
- CLT
- Cam sensor
- Crank sensor

There are few things that i am still thinking of (These determine the ecu requirements for inputs and outputs);
- Is it necessary to use PWM signal to alternator for charging control, or can that be let out completely, how would the alternator work without the PWM control?
- Can i bypass the A/C control from Engine ECU by taking the control signal directly from A/C control panel? (This would keep the A/C on in any engine condition as it wouldn't be controlled by ECU anymore)
So i am thinking to loop the signal in Engine ECU pin 57 this comes from Aircon and loop it to pin 22 AC compressor trigger.
If this is not possible this means 1 more input and 1 more output for new standalone ECU.
- Fuel pressure solenoid, i am not familiar with this but i am thinking it is used also with PWM signal, but can it be disabled somehow?

This totals at 16 outputs + possibly those open questions above AND 5 inputs, these are as minimum.

With MaxxECU you have build in MAP sensor and direct controller for bosch LSU 4.2 and 4.9 Wideband lambdas.
Any inputs regarding this kind of standalone setup is appreciated!

I am trying to use all original sensors so i can swap back the original ECU without hassle, if needed.

My first question is are you using an automatic gearbox or manual - if automatic, then you'll lose the torque reduction during gearshift, so your gearbox life might be significantly shortened.

I'll follow your format with what I deem necessary:

Outputs:
- 6x injector
- 3x coil - but plan for 6x if you decide to go Coil-on-plug and add the 3 extra wires into the harness. Dwell times actually vary based on load and battery voltage.
- Radiator fan is actually a PWM output, and this drives the fan at varying duty cycles and speeds based on ECT and road speed
- Idle Speed Control is a 4 wire stepper motor
- Fuel pump relay - there is a primary on/off, as well as a secondary output which switches between low/full voltage for reduced pump noise at idle and low usage
- Wastegate solenoid
- A/C Clutch

Inputs:
- TPS
- IAT - by default, this is within the MAF, so is not charge temperature, so your tune will need to accomodate the heating effect of the turbo/compression
- CLT (Engine Coolant Temperature)
- Cam sensor
- Crank sensor
- A/C request
- A/C pressure
- Power Steering request - to raise idle speed

Questions:
- The alternator does not need a PWM signal, it will just charge at full rate if disconnected.
- You do not really want A/C on all the time - you'll want to disengage it at high engine speeds/throttle (for more power), plus you'll need to know when it's on so that you can pre-empt the need to increase idle speed
- Fuel pressure solenoid is there to raise fuel presure during hot restart, it's probably not needed in an aftermarket ECU, but yes it would be a PWM-based signal


I definitely think making a patch harness is the right way to go if you think you may be swapping back to a standard ECU - but if you're capable of running the car on a standard ECU, what do you need a standalone for? The standard ECU can be reflashed, and there are people making good power with them.

Ok, thanks for the quick reply.
The gearbox is a manual so no need to worry about that.

So thats good to know that i can leave the alternator output empty.
A/C control then seems to be a must with ecu, i think i can manage that.
Power steering request, I think this can be managed ether way, with signal or without signal, need to think pros/cons for this.

-Another question then regarding FPR if the solenoid is not controlled at all does it give full pressure?
-For a standalone engine management, i think it would be beneficial to install IAT sensor with it's own wiring directly to new ECU, that way i can remove the stock MAF sensor and install the new IAT sensor in the intake manifold (or near it).

The standalone ECU is for easy of tuning and flexibility with step by step upgrades that can be made, but of course it is always sensible that you can detune your car to factory spec, so thats why i worked that this way would be the "easiest" for me.

With extra tuning effort you *could* tune around the extra load of A/C and P/S, but for the sake of 2 digital inputs, why not make use of the features provided by the ECU to manage this for you!

Yes the FPR has full pressure without the solenoid wired up - during cold start the solenoid activates and opens the FPR to atmospheric pressure, disconnecting the feed to the inlet manifold, so the fuel pressure does not get "pulled down" by the vacuum created within the engine. Aftermarket ECUs can deal with this by firing extra fuel in based on ECT.

If you're planning on removing the MAF, then a new IAT would be beneficial - you can get the correct plug to connect it in to the existing MAF wiring, and utilise the existing feed from the MAF to the ECU for temp. I would install it on the intercooler outlet hard pipe, so it is away from the heat of the engine.

Thanks again for this valuable info!

Yes that is possible to tune the extra load as the ecu has enough inputs, so i can manage the idle control with P/S and A/C.
I recon that best place for IAT sensor is as close as possible where the air enters in to the cylinders, as this info is used for ignition and fuel corrections.

Using the wire of the MAF sensors IAT sensor sounds great idea, but where can i find corresponding male connector for it?

I have now been summing this up.

The ECU i have planned is MaxxECU street, It has only 16 outputs.
This is not enough if i am going to use the original stepper motor idle control valve, now this got me thinking that it would be pretty easy to use a simple solenoid style IACV as it only requires 1 output from the ECU.
This is all because the pricing of these ECUs next model that have 3 more outputs and little bit more fancy stuff like bluetooth will cost up to +250€
Then again i am not very interested to use megasquirt as those are little bit outdated in my opinion, bulky casing and very mixed user feedback of the reliability.

What are you trying to achieve?

If you want to go cheap, get the hardware to tune the ECU and start there. You will need to spend significantly more on physical upgrades before it warrants a standalone. The bottlenecks (in the engine especially) are mainly physical to begin with, so addressing those first will give best returns and you can move to a standalone if and when you find it to be a bottleneck.

If money isn't such a concern, it seems to me that its pointless looking at an ECU which means you have to start thinking about how to work around having enough IO to do what you want (which appears to be to retain OE functions).
Looking at the MaxxECU options, they have a Evo4 plug-in with an adaptor harness. It may be worth checking with them whether that can be re-pinned to accommodate the extra IO for the 2 extra cylinders and any differences in pin locations (I believe its reasonably similar) as this could save a lot of time and effort.

As i said "standalone ECU is for easy of tuning and flexibility with step by step upgrades that can be made"
Benefits vs flashing the original ECU:
- Much faster tuning, for example you are on the dyno tuning your ECU for the best performance the cost is 150€ per hour. I think the standalone would survive from that much quicker.
- Multi fuel tables, E85 is available here and i can see many benefits from using it. I could use ethanol sensor to drive with e85 or regular gasoline at any time without worries.
- Engine safety functions can be easily implemented for the standalone ECU, Lean cut, Boost cut, Temp cut etc...
- All engine info live in the PC or smartphone.
- If i need to i can run different actuators or sensors fairly easily with standalone. Electronic boost controllers, Wideband lambda(this is a big+), oil pressure sensors, knock sensors all in the same ecu and that way all the info on my hands with laptop instantly and live.

Of course some of these functions may be in the original ECU with some flashing but you get the point.

And that jumper harness i am going to do it my self since for example that evo jumper harness costs 400€ and is only usable with higher end MaxxECU.
Another ECU options available is Ecumaster EMU Classic, seems to have pretty much all needed functions for my needs, have to take a better look at this.

I can see why you like the flashing of the original ecu, as it can give you fairly easily that extra 20-50 hp without touching any hardware, that's enough for most of us.

I'm fairly well aware of what you can and cannot do with flashing vs standalone, my point wasn't to push flashing over standalone but to question what you want to achieve in terms of modification goals, are you planning on forging the engine and otherwise expecting to invest significant amounts of money on upgrades to meet those goals.

~350hp can be had with "bolt on"s like exhaust, intercooler and minor tuning (increasing load limits and adjusting boost control).
You can get close to 400hp on standard turbos, but you need to modify the turbo housings to flow more exhaust, and you are at your injector limit. At this point, the OE ECU isn't struggling and there is enough freely available information on how to get it there and you can do pretty well even without a dyno.

So, if you are budget constrained, it makes little sense to invest in a standalone until you are past that point, in which case you are going to be spending a fair bit anyway.
Once you get to doing cams, injectors, turbos, rods, pistons, head bolts etc, 1,000€ difference in ECU cost may still be a decent amount, but it certainly isn't going to be the thing that determines whether you can afford to mod the car how you want. That doesn't even get into drivetrain support, OE clutch doesn't survive past an exhaust upgrade, even without tuning.

If you really just want a standalone because you like fiddling with stuff like that, no problem. If you intend to need it, save yourself in the long run and go with
A) A brand which you can readily get support for
B) The model which meets or exceeds your goals

I have weighted the pros & cons of standalone vs flashing that's why i'm gonna do it.
I am not here to argue about this, i know that especially you Kenneth have been researching and investing a lot of time for the stock ECU tuning.

I think i can now do a complete patch harness that will do the work for this, but that's still open question that where can i find the connector for the MAF sensor wiring adapter that i can use for IAT sensor wiring.
I can make a simple wiring diagram for this patch harness and post it here.

As I said, my concern is what appears to be compromise for short term reduction in cost rather than your choice of ECU. I have never found short term cost cutting to be worth while in the long run.

With your MaxxECU example, 250€ extra to go to the sport model actually looks worth while to me, as I would be thinking of chucking the IACV and trying to put a E-Throttle on there. That leaves you plenty of pins for extra stuff if you have the ECU and the connectors to mess about with them.

I got the MAF connector from here some years ago, it appears they are sold out at present, not sure if there are plans to get them back in stock. https://www.spoolinup.com/Evo-Male-M...ctor_p_39.html
This looks remarkably like the IACV connector, though that is just from memory: https://www.spoolinup.com/6-Way-Male...ctor_p_68.html female https://www.spoolinup.com/6-Way-Fema...ctor_p_69.html

I agree with Ken - I tried to "shortcut" the process by sticking with the OEM ECU + a piggy-back, but all it gave was extra headaches, limited functionality, and a high cost to tune because of the difficulty, plus the desire to retain "plug and play" compatibilty, but I then made changes which meant I couldn't run a standard ECU anyway.

Once I bit the bullet and bought a proper, decent ECU (LinkECU Extreme in my case, but would also seriously consider a Haltech if I were buying again from scratch), everything has just become SO much easier.

I've also converted to E-Throttle - and it is awesome. It frees up the 4x ISCV aux outputs for use, but it does require 3 extra Analog inputs, so there is a tradeoff... But the Link has 12 of these anyway, plus 4 dedicated temperature inputs...

Without the ISCV, idle is done via the E-Throttle (and ignition), which has been nice and simple to tune compared to the ISCV (and I knew that the ISCV was in reasonably good condition to start with), plus I've now also got a 1967 Ford Anglia with Anti-Lag and Cruise Control!

I would also *seriously* consider an ECU that's got a Wideband controller built in, or use a CANBUS controller (Link, Haltech, AEM X-series etc). I didn't, so I'm still using two analog inputs (one for each bank, as my exhaust systems are not linked) - so my fuelling isn't exactly totally accurate, as I've got minor voltage offsets between the two sensors.

That's one reason i posted this thread here, to get good knowledge of what is needed for the standalone ECU I/O wise, this determines the ECU model selection, as it appears in this thread for all oem functionality in the MaxxECU range a Sport model is needed. (This is probably the one i am going to chose)
Thanks Kenneth for the links of those connectors!

I have never liked a piggy back styled configurations as it is simply a mess, it's standalone or stock ECU for me.
These MaxxECUs have the wideband controller build in, i also like this as it's probably the most accurate way to tune AFR's.
Confused is your wideband sensors grounds in the ECU's ground, as this is the probable cause of the voltage offset?

Yes they're all grounded to the same place, one of the first things I checked! :)

My opinion is still to decide what your overall aim is - if you're wanting to replace the ECU for stock and have the car work, then that severly limits your ability to make modifications, which is when we're questioning the need for an aftermarket ECU, as even the stock ECU with Kenneth's modified ROMs provide some pretty nifty features!

If you remove that restriction, then you plan based on what you want as the end result after modifications - and it's often cheaper to do all of this work in one hit! I've been piece-mealing it over the years, and I've definitely spent more!