hengie

hey just want to ask a few questions....

my friend is getting a aftermarket ecu installed atm...(EMS) apparently the workshop said they are keepin the std coils and std ecu? is this piggyback?? can someone please explain this concept??....and will this modification eliminate that 3800 hesitation problem.(car is series 4 rx7 13b turbo btw)

Thanks guys

NZConvertible

They must be installing a fuel-only computer, so the stock ECU is retained to run the ignition. Given the low price of bottom-end fuel and ingition computers in this part of the world, I don't know why he's bothering with a half system.

YearsOfDecay

If he's keeping the stock ECU... most likely this will not eliminate the 3.5K rpm hesitation, the ECU itself usually needs to be re-soldered and properly grounded to fix this.

Apparently, he's doing a fuel mod only if he's retaining the stock ECU. A stand alone ECU like the Haltech I use can retain the stock coil packs, but the stock ecu goes bye bye!

THis could be anything from a simple SAFC to a Haltech additional injector controller to a true "piggyback" which actually does timing adjustments as well as fuel, but retains the stock ECU for emissions/ etc.

hengie

Apparently the workshop said his model of EMS has only 2 inputs which im guessing is fuel & ignition...the part i do not understand is why they are keeping the std ecu...the workshop has said for the air-con and etc to work u will need more inputs...and thats why they are using the std ecu..so this will not eliminate the 3800 hesitation?