The new walbro 440 is awesome! Its super quite. I have one of the original walbro 250's its terrible how loud it is..

 

Ok, I have some new data. The wires are there and ohmed out, so I ran some more tests.

As I saw the other day, when I just cycle the key, I don't get anything at the FPECU. However, while CRANKING, I get 3.2, or up to 5v depending on how many revolutions the car spins before it fires up. Once it is running, I get 3.2v at idle. I didn't rev it and see if the voltage would climb, but I suspect 5v is the high and ~3v is the low signal from the Aristo ECU.

Does anyone know what the trigger voltages are for the SC300 and JDM fuel pump ECUs? I may just need a newer GS300 FPECU to work with the Aristo signal voltages. Thoughts?

 

Ordered a 2GS FPECU. Will update once it's installed.

 

adam did you figure out the voltages?

i was just thinking you could check the ECU pinout section of the FSM if you have the aristo FSM and compare it to the sc300 FSM ecu pinout (for the FPC pin)

 

I don't have an Aristo FSM, but I know what voltages it is sending. I also found out that the SC uses 9v and 12v input, so the Aristo ECU even on high wont trigger the SC fuel pump ECU. Most 1st gen Aristos work with the SC ecu, but I have the last year JZS147 (97) and it must have been a bastard year for the FPECU.

 

I'm almost 100% positive it's (SC300) 9v then 12V at a certain rpm/throttle. 9V keeps it quiet and keeps the heat off of it.

 

The SC300 and USDM Supra do use 9V and 12v trigger voltages. I just got my 99GS300 FPC in today. This thing is clearly more robust than the SC part. Check out the difference in the size of both the heat sink and pins. I am waiting for my connector housing and terminals to come in and I will install this beast and hopefully have a quiet cabin again.

 

So it's regulating the voltage at idle to keep the cabin quiet versus just having full voltage to the fuel pump 100% of the time? Sounds like it would complicate things even further.

 

Odd suggestion, but the Aeromotive Stealth 340 fuel pump, while not any quieter than the Denso TT pump, DOES have a "deeper tone."


Not sure if that helps at all at this point

 

If this does not work I will look into other options I guess. Its funny because loud exhaust does not bother me like this fuel pump. I think it's the super high pitch. I also like the idea of the pump turning off when the engine is off.

 

Well this blows. I cannot for the life of me get this thing to work correctly. It acts just like the 12v mod when plugged in. It sounds crazy, but I think it may be be because my fuel pump is grounded to the chassis. Looking at the GS diagram (Thanks cartmill), it looks like the GS isolates the fuel pump from ground. I looked at some pics of the GS pumps, and they appear to be encased in a big plastic fuel filter housing. I think the constant ground is essentially bypassing my FPC now

This sucks! I don't know of any safe way to test my theory either.

 

After further reading, it appears I may have a bad FPC. If I supply 12v to B+ and ground E, I get battery voltage across FP and FP-. Lame. This car is my nightmare