agent004

iTrader: (13)

I am adding a second fuel pump to my fuel system. I expect that this will make fuel temperature at the rails go up due to the extra work from the second fuel pump.

Is it necessary for me to setup my ECU to trim the basemap for the change in fuel temperature, or is the effect so minor that it will not significantly impact my AFR's?

IRPerformance

iTrader: (41)

I don't feel it is needed. Most cars don't have a fuel temperature sensor. If you have a rail that has the provision for it, sure run it but I wouldn't go out of my way.

j9fd3s

iTrader: (3)

the training manual http://foxed.ca/rx7manual/manuals/93...highlights.pdf

mentions that they use it for hot starts. so if you wanted to play with it, it would be almost the last thing to tune

agent004

iTrader: (13)

I did see page F-29 where it mentions that it is used for the fuel pressure regulator control for hot start assists. But if you go further down to F-37 you will see that fuel temperature is one of the inputs into the basic fuel correction map on the stock EDU. Then even further down to F-43 you will see that there is also a timing correction based on fuel temperature.

IRPerformance

iTrader: (41)

There is also a solenoid for the fuel pressure regulator to assist hot starts but most of us remove that and it doesn't seem to make a difference. Does your ecu have a correction factor for it?

agent004

iTrader: (13)

I got rid of the hot start assist solenoid that cuts out the vacuum to the FPR during hot starts a while ago. I haven't had any hot start issues; I just had to tune the cranking injection pulse vs coolant temp curve carefully.

The AEM Series 2 has a "user fuel trim" which I can assign as a correction for fuel temperature. The Power FC did have a designated fuel temperature correction table also.

The last of my parts for the fuel system build just showed up today. I am going to start at the fuel tank and work my way to the engine bay. If I am not too sick of working on the car by the time I get to the fuel rails, I will connect the sensor to the ECU and log fuel temps running one pump, then compare to temps running both pumps. That will be a starting point to determine the significance.

thewird

iTrader: (8)

The 96+ PowerFC's list a -3% temperature correction at 20 degree's on the base map. Just thought I'd throw that in there.

thewird

RENESISFD

iTrader: (13)

IMO, as we increase the HP significantly the fuel temp is more important as more fuel is being injected into the motor, this becomes even more important when running E-85 as you need even more fuel. On my setup (3 044 pumps) I added a fuel cooler at the rear of the car to help control the temps. Although I have a flex fuel sensor which is capable of reading fuel temps.... The Haltech sport ECU is unable to take advantage of that.

agent004

iTrader: (13)

I am planning to leave my current fuel rail setup intact with the fuel temp sensor installed in the secondary rail. I will log the base temp with just one fuel pump running. Then I will log the temps with both running all the time. Then I will take some logs with my staged pump setup.