1JZ GTE VVTI Swap Code 78 Question
04-05-13, 10:59 AM
#1
1JZ GTE VVTI Swap Code 78 Question
Hi guys, how's everybody doing? I hope everything is going well.
My SC400 is in a finishing phase of the 1JZ GTE VVTI with R154 swap right now.
I got to drive it yesterday and it sounded really nice and smooth except for the misfiring (CODE 78: FUEL PUMP).
I've done quite a lot of research regarding this issue and it seems that the only answer I can find is to bypass the relay.
Can someone give me a better step by step explanation?
Thanks and I really appreciate it!
-David
My SC400 is in a finishing phase of the 1JZ GTE VVTI with R154 swap right now.
I got to drive it yesterday and it sounded really nice and smooth except for the misfiring (CODE 78: FUEL PUMP).
I've done quite a lot of research regarding this issue and it seems that the only answer I can find is to bypass the relay.
Can someone give me a better step by step explanation?
Thanks and I really appreciate it!
-David
04-05-13, 02:48 PM
#3
you can test it by jumping the +b to FP on the diagnostic connector. that supplies battery voltage to the pump so use a proper wire to do this. if the car runs better then doing the 12v mod will help you fix it permanently.
look up the 12v mod, there are 2 ways.
1st is the shortcut, and thats to just bypass the fuel pump ecu, and tie the input and output wire together.
works great for supplying voltage to pump, but problem with this is the pump is on as soon as you key on, which is very dangerous if you get in an accident. you have lost all the safety of the fuel ecu.
2nd option is to use a regular automotive type relay and you use the output of the regular fuel pump ecu to trigger the relay, which gives you battery voltage through the relay to the pump. this should make your car run good again.
problem with this is you may still have that code because part of your problem is how new your ecu is.
So you have a third option as a vvti swap, the reason you are probably getting that code is because the wire that connects to the fuel pump ecu is either not connected right, or if it is the car your ecu came from may have used the other type of voltage toyota uses on newer cars for the fuel pump ecu. 2.5 and 5v instead of the older 9v/12v, which means its sending the wrong signal to your fuel ecu. In this case you can just install a fuel ecu similar to the one the 1jzvvti had to get also stock operation back.
read this
https://www.clublexus.com/forums/2077083-post10.html
only thing funny about that post is that im using a non-vvti aristo ecu and my stock fuel ecu works just fine.
Im going to assume he meant the vvti motors on the newer aristos etc.. which makes sense because of the 98+ part.
look up the 12v mod, there are 2 ways.
1st is the shortcut, and thats to just bypass the fuel pump ecu, and tie the input and output wire together.
works great for supplying voltage to pump, but problem with this is the pump is on as soon as you key on, which is very dangerous if you get in an accident. you have lost all the safety of the fuel ecu.
2nd option is to use a regular automotive type relay and you use the output of the regular fuel pump ecu to trigger the relay, which gives you battery voltage through the relay to the pump. this should make your car run good again.
problem with this is you may still have that code because part of your problem is how new your ecu is.
So you have a third option as a vvti swap, the reason you are probably getting that code is because the wire that connects to the fuel pump ecu is either not connected right, or if it is the car your ecu came from may have used the other type of voltage toyota uses on newer cars for the fuel pump ecu. 2.5 and 5v instead of the older 9v/12v, which means its sending the wrong signal to your fuel ecu. In this case you can just install a fuel ecu similar to the one the 1jzvvti had to get also stock operation back.
read this
5. Many people re-wire to run 12v to pump constantly. This
will work fine but the pump will be a little noisy inside cabin.
I change the fuel pump ECU to 98 Supra NA and here's why:
-Fuel pump is designed to run in two modes:
High (Battery Voltage to Pump) for Starting and High Load
Low- (9v to pump) for Idle and Low Load
-The Aristo's ECU puts out 2.5v to signal low and 5v to
signal high through the FPC Circuit. The SC300's Fuel Pump
ECU uses a 9V(Low) and 12v(High) signal just like the
Supra Turbo's. The 98 Supra Non-Turbo had an ECU
change. This new ECU uses a 2.5v-5v FPC Signal and so
it's fuel pump ecu was changed. This makes the 98 Supra
NA fuel pump ecu suitable to use with the Aristo ECU.
**Please note the 97-98 Supra Repair Manuals are
incorrect. The 93-98 Supra Turbo never changed ECU
design and so uses 9v-12v FPC signals not 2.5v-5v.
Currently: I'm working on designing a relay system so you can
use the sc300 fuel controller with Aristo ECU. Watch for this in the
future in Part IIa: Electrical
will work fine but the pump will be a little noisy inside cabin.
I change the fuel pump ECU to 98 Supra NA and here's why:
-Fuel pump is designed to run in two modes:
High (Battery Voltage to Pump) for Starting and High Load
Low- (9v to pump) for Idle and Low Load
-The Aristo's ECU puts out 2.5v to signal low and 5v to
signal high through the FPC Circuit. The SC300's Fuel Pump
ECU uses a 9V(Low) and 12v(High) signal just like the
Supra Turbo's. The 98 Supra Non-Turbo had an ECU
change. This new ECU uses a 2.5v-5v FPC Signal and so
it's fuel pump ecu was changed. This makes the 98 Supra
NA fuel pump ecu suitable to use with the Aristo ECU.
**Please note the 97-98 Supra Repair Manuals are
incorrect. The 93-98 Supra Turbo never changed ECU
design and so uses 9v-12v FPC signals not 2.5v-5v.
Currently: I'm working on designing a relay system so you can
use the sc300 fuel controller with Aristo ECU. Watch for this in the
future in Part IIa: Electrical
only thing funny about that post is that im using a non-vvti aristo ecu and my stock fuel ecu works just fine.
Im going to assume he meant the vvti motors on the newer aristos etc.. which makes sense because of the 98+ part.
04-11-13, 07:29 AM
#5
for the long run just make sure its bypassed the right way.
If you can hear your fuel pump come on and saty on with the first click of the key and the motor isn't running, then you have no safety features left, you will have to pull out the key to stop the fuel pump in an emergency, and even then the pump will go on for about 6 seconds before it stops. good luck.
If you can hear your fuel pump come on and saty on with the first click of the key and the motor isn't running, then you have no safety features left, you will have to pull out the key to stop the fuel pump in an emergency, and even then the pump will go on for about 6 seconds before it stops. good luck.
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