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DBW how to keep it save and working well

EFI Wiring Fundamentals

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Discussion and questions related to the course Motorsport Wiring Fundamentals

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Mistakes on DWB installation on wiring can often show-up after some time due to bad wiring installation. Even the professionals get it wrong not being instructed on the subject making them just as good or bad as any home made hobby BOB. I think we can all agree on something! Safety first!


Connect all wires to the TPS and accelerator peddle sensor and feed them direct to the ECU.

Most DBW system have a 2 signal sensor so please do use them all and connect them separate to your ECU.


Clean line of supply to the TPS and accelerator peddle sensor(s). OK not all ECU have a load of 5V and sensor ground outputs to facilitate separate power supply to the BDW system sensors but please do make these 5V and sensor supply connections as close to the ECU as possible. And yes I know doing a DBW upgrade on your engine. Yes there is already some wiring for a TPS or throttle plate sensor that happens to have a 5V and sensor ground in it but this supply also is in use for your MAP/MAF coolant temp and so on so not a smart thing to do using these wires as a power supply to the DBW sensors. Example your bulkhead connector goes bad getting a bad connection on the 5V sensor supply. Sensor 5V pulls the voltage on the TPS or throttle plate sensor up so lose part of the 5V due to resistance in the bulkhead connector and the TPS or throttle plate sensor signal voltage to the ECU will drop as well. The ECU will say I’m not on target and opens the throttle valve if you done your DBW set-up wrong and the ECU dos not go into limp mode. @ first maybe having no idea what is going on later on find out in a data log lost of other sensor go bananas as well. A DBW system must be seen as a separate system to the rest of the engines systems. It is vital to you and others to stay save this way.


Know your ECU and DBW sensor set-up. Most modern DBW system use a dual signal sensors. Two types are in use. Hi and low signal. Low usually is half of hi signal so if hi signal reads 4V low signal will be somewhere around 2V.

Cross signal. As the words says signal 1 to signal 2 is inverted so if 1 reads max volt signal 2 reads minimum voltage. Cross signal is the safest variant so if your sensor(s) can we wired in that way use this variant please.

There are no stupid questions. Keep asking stuff so you know your installation dos what it needs to do.


Sensor tolerance. Most ECU have a setting that allows some tolerance or drift on the sensor signal inputs for the TPS or throttle plate sensor and accelerator peddle sensor. So far only the accelerator peddle sensor of a Toyota Hilux diesel did not have a linear sensor signal but please make this tolerance as small as possible. It’s yours and others safety on the line here.


Minimise connectors involved in the DBW wiring. Personally I’m not a great fan of autosport connectors. The seal on the back of these plugs often dos let water into the plug with some interesting results. Seal them off properly or do not use them.

great advise

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