Piggyback Setups

If my vehicle does not have the aftermarket support for a p&p or patch loom option. What are my options if I want to keep everything functional with just engine control via stand alone ecu? Its a 2008 Sienna front wheel drive with a 2gr engine with a 5 speed auto. I know what many of you are thinking..why?!... Well when family compliance comes into effect we are left with to play with what we have. Plan is to slightly build the engine, boost it and throw in a modified converter from Houges. However, I am yet to figure out a simple solution to figure out the complexities of using a stand alone, have everything working and happy in the vehicle. Any ideas or solutions guys?..

hello this can be done using a link kurofune ecu, im sure they are others that do it but this is one i know will work well and is designed as a piggy back ecu

check out linkecu.com kurofune

Regards Ross

Thank you Ross for your support. I have looked into this option before but aren't these ecu made specifically for older model jdm vehicles? F con type or something like that. They make adaptor plugs for Siennas? All I have seen was common sport jdm or usdm options. Please see attached file for the ecu plug difference. Also will this even run the 2gr engine with 4x vvt system? Sorry I am still very new to the tuning scene but I still have a good deal of automotive knowledge to not ever visit a repair shop lets say. Example, say I wire in the the kurofune directly to my stock loom with all the common ins/outs for the engine side and leave the stock ecu to handle the rest will that work? I can see few problems arise with shared signals between engine, trans, and chassi. I have seen g4 fury offered for many 2gr plants but its all stand-alone setups.

Yes you would need to make your own adapter harness, I doubt HKS would have one for that model.

But the reason Ross suggested the Kurofune is it is specifically designed for working in piggyback installations and has several important features that most other standalone type ECU's wont. One feature is the trigger inputs are "differential" so it allows you to share the trigger sensors without disturbing the signal to the factory ECU. Some factory ECU's wont work if you ground one side of the crank sensor like most aftermarket ECU's do. The second feature it has which is not common in standalones are configurable analog outputs (controlled by 3D tables), these are used to "fool" the factory ecu to keep it happy. Often you will need to simulate signals such as MAF and oxy probe to keep the factory ecu happy and the trans control working.

The Kurofune can do the 4 VVT cams no worries but requires a separate module for E-throttle. It would probably be easier to leave the factory ecu controlling throttle but that brings with it drivability issues.

Having said that, it would not be something I suggest you take on - with modern auto trans engines with E-throttle, the control strategies can be very complex and it will be an absolute nightmare with many compromises made trying to get it all to work together in harmony. It will unlikely ever be an easy to drive family car again.

Thank you very much Adam; very useful info. Looks like I will have to dive in deeper and do more reseach into the dbw issue.