rcsup1

iTrader: (1)

Hey all,

I searched but could not come up with a definitive answer. When upgrading to a TTdenso pump is the 12v mod required in order for the car to run ?

I installed the pump yesterday and the car would not start until I did the 12v mod.
I really did not want to do this since I would like to keep the dual mode operation.

Ali SC3

iTrader: (10)

did it run fine before you swapped out the pump?
could be something with the fuel ecu.

rcsup1

iTrader: (1)

Yeah it was running perfectly

philauldridge

There is no reason it shouldn't operate fine on the lower voltage. I'd check to be sure that the FP ECU is in fact putting out any voltage at the low setting.

However, you say you've already done the mod. I wouldn't worry about it. I've run my pump continuously at the 12V setting for several years, and never experienced a problem with it.

Cleanshots

iTrader: (2)

the bigger pumps cant function like that mine did that too. there is nothing wrong with it getting 12v you get better fuel. leave it dude!

Ali SC3

iTrader: (10)

yeah, the 12v works pretty well unless you like to listen to the radio with the engine off.
you get used to the sound of the pump though.

SC51

iTrader: (3)

Rite on and as long as you have the key clicked once on acc or w/e the pump should shut off after a min.

YeA 2jZ

iTrader: (15)

So when u do this mod if u have the key in acc to listen to the radio the pump will stay on ?

rcsup1

iTrader: (1)

The biggest thing is the noise for sure and running the pump like that is pretty needless for my goals at this point. Anyone know if the supra tt fuel computer will work in our cars ?

Ali SC3

iTrader: (10)

bingo, any position but off. doesn't bother me much cause I either am sitting there with the engine running to let it cool down some or I just turn it off. you could run a relay to turn it on only when the engine is on. do a search for the wiring diagram.

YeA 2jZ

iTrader: (15)

ok but lets say i am waiting on someone and i am listening to the radio engine off would and is the pump actually pumping fuel into the engine or is it just active ???

SC51

iTrader: (3)

Yes anytime the pump is on the fuel system pressurizes, but it just returns to the tank anyway. If you go from driving to directly going to the acc position the pump shuts off, but if you turn it all the way to on (like to mess with windows) then turn it back to acc it will take a bit for it to shut off... you'll be fine

Ali SC3

iTrader: (10)

the pump will be on but no fuel goes into the engine.
it goes from the pump through the rail and back from the return line.
Since your engine is off the injectors are closed, so no fuel gets into the engine.

most cars have a fuel pump prime of a few seconds, where the pump comes on to pressurize the system, just think of it as a long priming. no biggie.

The 1 dangerous situation I could think of is if something happens (accident or something) that causes your car to spring a fuel leak. normally this would cause the engine to die (lack of fuel) and when the engine shuts off so does the pump.
with the 12v mod, you would have to still pull the key out, and then it would still pump fuel for another 5 seconds or so. as unlikely as this is it can be avoided with the use of the stock fuel ecu as a trigger to a relay which gives 12v to the pump.