tuning petrol 4.2 efi

[menace 2]

have removed all the gas set up completely...couldnt get the rego done because I didnt have what they called a de-commissioning cert ...that one caught me out !...anyway going to get that tomorrow....they only have to lift the bonnet etc and see there isnt any thing associated with gas and it is petrol only...but they want me to leave the car and they will call me when it is ready ????....(another shitfight coming ...lol) anyway , after having been on dual fuel , do I have to re-tune it due to now being straight petrol and if so , does anyone know how do I go about doing that with the injection....cheers

[menace 2]

thanks for that Ynot....didnt think of the fuel hoses and never knew about the plugs....cheers

[ozzyboy]

mine is a duel fuel, however I rarely use gas. Wasn't running rough or anything like that. Had mine dyno tuned and wow what a difference. A very noticeable difference in grunt, and I now get an extra 80 km ... yes ... 80 km out of a tank !! That was tuned to run good on gas and petrol. Gas being removed soon for a lra, so I will definantly get it retuned.
ozz

[Bloodyaussie]

Make sure spark plugs are standard spec and not LPG spec, other than that check the ignition timing. The fuel and ignition maps in the ECU won't have been changed.
I would be checking ALL fuel hoses VERY closely for fine cracks. If the car has been run predominately on gas the fuel hoses can dry out and crack, many a dual fuel car has gone up in flames for this reason.

Fuel hoses from the tank?? the pump is always running fuel on a return?? or is there other hoses around the intake?

[Parksy]

In terms of tune up there isn't much to do apart from making sure that components are clean and serviceable. Your injectors may need a clean, especially if you've run on gas for extended periods. Make sure your throttle position sensor is at .4 volts, disconnect the green plug at the back of the plenum and set the timing to 10degrees btc. Then adjust the idle screw on the back of the plenum as necessary to get the correct idle speed ~550 rpm. Disconnect the battery for 30 mins to reset the ecu to start "fresh".

[Drewboyaus]

mine is a duel fuel, however I rarely use gas. Wasn't running rough or anything like that. Had mine dyno tuned and wow what a difference. A very noticeable difference in grunt, and I now get an extra 80 km ... yes ... 80 km out of a tank !! That was tuned to run good on gas and petrol. Gas being removed soon for a lra, so I will definantly get it retuned.
ozz

I was under the impression there wasn't much that could be done to improve the tune of TB42e on a dyno because the ECU isn't tuneable. You would need a Nistune board (or similar) to make it tuneable.
Happy to be wrong though.....


Tip tip tip......tap tap tap....

[Little Mick]

Wouldn't hurt to change the fuel filter and run some injector clean through it.

[YNOT]

I was under the impression there wasn't much that could be done to improve the tune of TB42e on a dyno because the ECU isn't tuneable. You would need a Nistune board (or similar) to make it tuneable.
Happy to be wrong though.....

While it's true that you can't "tune" through the ECU, there is no need to. For a standard or near standard engine the fuel and ignition maps that Nissan programmed in work just fine. There are many other aspects that can affect the tune of the engine. Ignition timing, spark plug heat range and general ignition system condition, fuel injector condition, fuel pressure and flow, air filter condition, air leaks in the inlet anywhere between the air flow meter and the cylinder etc etc etc. Even the condition/calibration of the coolant temperature sensor can have a major affect on performance. In simple terms any of the things I've just listed (and many more that I haven't) can detract from the engines original performance.
On the other hand a well designed free flowing exhaust system and snorkel can improve power and fuel economy without needing to "tune" the ECU.