Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Installing a wire in standalone ecu

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads


Hey Andre and fellow tuners,

I have some questions when it comes to installing a wire in standalone ecu into a vehicle that is not supported by a plug and play package. It could be any brand ecu, link, haltech etc I am not referring to any specific brand.

I want to delve into some things that the courses have not specifically addressed but you are likely to encounter in the real world. Most times, Andre you are using plug and play set ups that comes with all the required calibration data. My question is, when installing on a vehicle that is not supported specifically, how is this addressed ?

Would you attempt to find calibration data for the engines factory, map/maf, IAT, ECT and injectors? Or would the correct thing to do be to change all of these sensors to sensors sold by the ECU manufacturer that come with the required data?

I have been re-doing all my HPA courses and I can see the importance of having proper injector characterization data in particular. On this one, I am leaning on recommending always changing the injectors to well supported ones eg Injector Dynamics, but the problem I foresee happening, at least for me, here in Trinidad, "tuners" have been setting up stand alones on engines with no characterization data and I assume simply correcting for it on the main fuel table. With this in mind, as someone new coming into the industry, it'd be pretty hard to now tell someone that they need to go spend $400+ on a set of injectors with proper characterization data. I guess the tuners and customers alike here lack the appreciation of doing this Same goes for all the other sensors I have mentioned.....I rarely hear of people changing the factory sensors either so I assume the data input here in Trinidad is just maybe a best estimate. Any advice on dealing with a cultural issue like this Andre/fellow tuners?

Lastly, and this is directed to Andre, have you guys considered doing a webinar and delving deeper into trigger sensors? The courses touch on this but don't really go into great detail I've found. For instance, I lack the understanding of the different types of triggers wheels out there and exactly how they work....how do I know if the ones fitted on the car from factory can be used back on my stand alone? Or is this another case of what I was speaking of above and the sensor/s need to be changed out? I've heard numbers being thrown around when it comes to trigger wheels and to be honest I havent got a clue what they mean. I think a webinar going into some more detail may benefit all of us, what do you guys think?



You will find most aftermarket ECU's will have options (different calibrations etc) for most sensors (water temp, air temp etc) which will cover major brands, in some cases where the calibration isn't available you will be able to create your own calibration table, test the sensor and input the calibration data (very rarely needs doing). Generally the time consumed doing this out weighs replacing the sensor with a supported option.

As for other things like injector data. Once again most aftermarket ecus will give options for deadtimes. Unfortunately though getting information for short pulse width adder and minimum pw for most factory injectors in pretty impossible.

In the perfect world having all the data possible for injectors is ideal however this isn't always possible and customers don't want to pay for something if their current injectors are up to the task. In this case when the data isn't available then generally I will zero the short pulse width adder and minimum pw and just use deadtimes. I will start with a best guess/base deadtimes and then tweak them depending on fuel map shape and curve at lower vacuum areas and idle and unfortunately a bit of fuel map fudging needs to be done. Like I said its not the ideal situation.

With trigger systems and after market ecus this one may require some customization. If the ecu doesn't support the trigger system fitted to the engine then you may need to make a custom system/wheel and fit it to the engine and set it up in the ecu.

As you said you don't have much knowledge towards the trigger system ill explain a little further.

Lets start with a common aftermarket trigger system 60-2 which you may of heard.

Whats this means is that there is a trigger wheel on the crankshaft (or even camshaft) with 60 evenly spaced teeth but with 2 missing (so essentially its 58teeth with a large gap where 2 teeth should be) these missing teeth give the ecu a reference point as to where in the cycle the engine is. If you just had 60 teeth the ecu would have no idea where tdc is, but with 2 missing (and the offset of those 2 missing teeth and tdc is put into the ecu) the ecu now knows where tdc is. This doesn't have to be 60-2 though, it could be 12-1, 24-2, 36-2, 24-1. anything really depending on what you can fit and what you want for resolution, as long as the teeth are evenly spaced. The you go one step further and add a sync pulse, this is a single pulse on the cam shaft (when using main trigger on the crank). Now not only can we tell the ecu where tdc and crank position is we can also tell it which cylinder it is firing on. Also when you run a sync you don't need to run any missing teeth on the crankshaft trigger as the cam sync will do that instead. Now you could have a 60 tooth crank and single sync, or if you want you can still run a 60-2 plus a sync, basically whatever you want providing it is evenly spaced.

The problem with factory systems is they like to customize their trigger systems and have their own trigger pattern to work with their ecu.

Have a look at the photos I have attached. These are from a Subaru EJ Motor

Notice how the crank pulley has 6 teeth all with different spacing's and the cam pulley has 7 teeth in different locations as well. The issue becomes (if the ecu you're using doesn't support this particular trigger system) trying to tell the ecu how many teeth the pulley has and being able to input a sequence in when they occur and the gaps between them as they are all different gaps. Its very easy to get wrong and if you're out by 1 degree of one tooth you will have erratic timing and most likely log trigger faults. Hence why in this case (once again if the ecu doesn't support this particular trigger system as most ecus will have an option labelled subaru ej20 etc) then you would be better off to make your own custom 60-2 with a sync or whatever you want.

Hope that all makes sense?

Attached Files

Wow Chris,

Thanks so much for taking the time to go through all of that. I have a much clearer picture now on it all.

As for what you were saying about the sensors and injectors, would it be as easy as having a look at the sensor/injector physically and looking for specific indentifier numbers then looking through the ECU options? Or is it listed by engine code? If it is, then you may run in to problems with engines that have the same engine code but use different sensors on different cars/models.

I am leaning to using a Link G4+ ecu on a suzuki M15A engine. If its not too much trouble, can you tell me if this engine is supported in any way on the Link software or am I in for a rough ride in getting this to work on the engine?

Thanks again for all the info and the pictures, that was the first time I really saw images and had that explained!



Happy to help

Generally for water tempr sensor and iat etc they will list the calibration as the part number (which should on most sensors) or if it is a standard NTC sensor etc.

I know Link support several Suzuki engines including a few from the Swift which I believe comes with the M15A (Along with other engines)

I would suggest to be 100% sure, email Link and ask if they have a trigger mode suitable or know if the G4+ can work with the Suzuki M15A trigger pattern.


Hi Chris,

Thanks again for that. I will surely email link as well.

One last question for you. In the scenario I described, you are installing a wire in ecu into a vehicle not specifically supported by the ECU manufacturer. Is it necessary to always create an entirely new wiring loom that goes from the ECU to all the engines sensors? Particularly if you are reusing most of the factory sensors that are already in place on the engine, is it possible/advisable to re-use the factory wiring loom that is already in place and simply cut the factory bulk head connectors off the harness and then wire in the stand alone ECU harness to this?


Hi Chris1388,

I think I can help with your last question , well if your car have the electrical system in good shape : wiring, connectors , fuse boxes,

relays , etc is a good idea to stay with your factory harness they are very good quality and work very well for most aplication ,

they are very well designed and constructed they are well crimped , insulated ,etc.

If you have to cut the factory bulkhead connector and work with the factory harness is a good idea to get the factory service manual of

your car they are very well detailed and on the electrical system section of the manual there are all the ecu pins numbers of the connector that correspond to each sensor and actuator . with the factory manual the ecu manual and voltemeter for measure volts , continuity and some time you could install an afterrmarket ecu with the factory harness is not easy but if you take the time to do it properly it fits and work very well. If the proyect is an engine swap or the electrical system is in bad condition for example too much year of usage , I think more that 15 or twenty years is too much for the wiring for a high performance aplication is better to make a new custom wiring for the the new ecu.

Other problem is if you bought you car second hand and have some years with bad technical service you dont know what is behind and below all the insulated corrugated tubing and insulated tapes then its posible to have electrical problems when is time to tune the engine and the problems are related to bad fixes before you bought the car , if you look the engine bay and it looks like other people have been fixing some electrical systems before is better to inspect deeply before install the aftermarket ecu with the factory harness, that is another case for a complete new wiring.

Thanks Chris Wall, very clear and good explanation for the trigger systems and general sensors .

I am familiar with injector deadtimes corrections but could you explain a little the term short pulse width adder

is a function for a particular ecu brand ?

Hi Julio,

Thanks for your response, makes sense.

As for your question, a short pulse width adder is a form of injector characterization that some ECU's, particularly some OEM ECU's, use to help accurately describe the injector flow behavior. The injectors flow does not vary 100% linearly with duty cycle change and as such the short pulse width adder is a table that attempts to tell the ecu at what duty cycle it needs to inject more fuel (short pulse adder) over what it is currently injecting in order to properly characterize the flow rate. I hope this helps, there is a webinar on injector characterization, search for it in the webinar section, it is very informative.

Thanks Chris,

Your explanation give me a good idea of that term , also going to look for the webinar.


As Juliotdr was saying, using your factory harness and cutting off the bulkhead etc is a good way to replace a factory ecu. OEM looms are very robust and they spend a lot of time and money designing them to last. Do bare in mind though they are also done to a budget to keep costs down. I would usually rewire the engine myself if It was to be for a race car or if we were uncertain about condition of the current loom or if we were wanting to remove a few systems and simplify the loom.

Juliotdr, Chris was bang on with the explanation about an injector not being 100% linear. The short pulse width adder is to compensate for the difference in injector slope at low PW. Have a look at the photo I have attached below. At the low PW you can see the difference in the way the injector flows. In order to get good control of fueling and injector operation at these low PW's we give the ECU the low pw adder calculation to compensate for the change.

A link to the Webinar is below, I recommend watching it :)


Attached Files

Hi Chris,

Thanks again for the response. Making my own wiring loom is something I would love to get into doing, I have done the wiring course offered by HPA but its pretty basic and doesn't delve too deep into things. Hopefully they build on this and bring out a more advanced class in the future.



Sometimes the best place to further develop your skills is to jump right in. You always have the course to fall back on if you need to reference anything. Plus the forum, will try and help where possible.

Thanks Chris.Wall for the picture it helps to completely understand the explanation.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?