Help with Braineack built MS3 - fuel pump circuit
#21
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Cpt. Slow
iTrader: (25)
Joined: Oct 2005
Posts: 14,477
Total Cats: 1,228
From: Oregon City, OR
Thanks, kinda saved my ***. Those settings were -7 with a 24900 bias resistor, and 70 with a 249000 bias resistor. Worked well enough to get through the dyno tuning, but it wasn't reading correct. Anyone know the correct bias resistance?
#23
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Cpt. Slow
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Total Cats: 1,228
From: Oregon City, OR
Yes, resistor swap fixed the fuel pump, car dynoed at 247. Much more and he needs injectors/rods.
Alternator sucked, running 11.2-12.7volts the whole time. He said he had some issue with the ecu regulation, on the old ecu, is the MS setup to regulate one? That or he needs a 94-97.
Alternator sucked, running 11.2-12.7volts the whole time. He said he had some issue with the ecu regulation, on the old ecu, is the MS setup to regulate one? That or he needs a 94-97.
#25
Need help with a fuel pump issue on my MS3X. This is for a 99 using the MSPNP-pro base map.
I'm not able to turn the fuel pump on. Everything else works. When I jump the FP pin on the diagnostics port to force to pump to run and start the car it works just fine. As soon as i disconnect that jumper the FP dies and the car will slowly start to run lean and finally stall when it looses enough pressure.
When I use test mode to trigger the fuel pump I can not hear it running.
I've set it up on the bench in test mode and am reading 0.6V with the output set to off, 4.6V with is set to on, 1.7V when pulsed at 25% DC. So it seems to be functioning. I'm not sure why it's only 4.6 V. Battery in is at 12.4V. The 5V on the proto is 5.08V.
I've attached a picture of the circuit and all diodes look to be the right way. All diodes look to be in the right orientation.
When I swap it back to the stock ECU it primes and starts right away without needing the jumper. I'm stumped
I'm not able to turn the fuel pump on. Everything else works. When I jump the FP pin on the diagnostics port to force to pump to run and start the car it works just fine. As soon as i disconnect that jumper the FP dies and the car will slowly start to run lean and finally stall when it looses enough pressure.
When I use test mode to trigger the fuel pump I can not hear it running.
I've set it up on the bench in test mode and am reading 0.6V with the output set to off, 4.6V with is set to on, 1.7V when pulsed at 25% DC. So it seems to be functioning. I'm not sure why it's only 4.6 V. Battery in is at 12.4V. The 5V on the proto is 5.08V.
I've attached a picture of the circuit and all diodes look to be the right way. All diodes look to be in the right orientation.
When I swap it back to the stock ECU it primes and starts right away without needing the jumper. I'm stumped
#26
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Cpt. Slow
iTrader: (25)
Joined: Oct 2005
Posts: 14,477
Total Cats: 1,228
From: Oregon City, OR
It's not providing power to the fuel pump, it's giving the fuel pump relay ground. So you'd wanna check for continuity to ground when switching the fuel pump on/off. But if it has 4.7 volts that's not a good start.
#29
current plan is to order the components of that circuit and build it on the proto area and bypass the original circuit.
#31
would it be possible to use i different I/O pin for the fuel pump. It looks like it can not be remaped in the fuel pump setting page. But in the programmable on/off setup one of the inputs is fp_duty. So if I set the fuel pump to open loop pwm then setup a programmable output to trigger on when fp_duty > 0 and wire that to the fuel pump harness pin would that work?
Is there a suitable output on the MSX card to control the FP relay without extra circuitry?
#33
No, the default FP circuitry is not working. I probably shorted something and damaged a components. I'm trying to figure out a work around. you can not change the maped pin in the Fuel pump set up page. But if I put it to open loop pwm then I should see FP_duty > 0 any time the fuel pump should be running.
Then I can go into the programmable I/O page and setup an output that is triggered to turn on anytime FP_duty is greater than 0. That way it should hopefully match the on/off relay functionality of the FP control as a band aid fix.
Then I can go into the programmable I/O page and setup an output that is triggered to turn on anytime FP_duty is greater than 0. That way it should hopefully match the on/off relay functionality of the FP control as a band aid fix.
#38
Much learning from this project. I'm just glad it's running my engine now except for the FP issue. The end is in sight.
DIY shipped out my order last night so I should be able to rebuild it mid next week.
No solder bridges on the two transistors.
#39
So I gave the re-map "work around" a shot and it worked beautifully. Just in case someone else has a similar problem and stumbles upon this thread and wants to use the temporary band aid solution.
I used the VVT output pin and on the programable I/O page set it to on when FP_duty > 1.
The fuel pump primes on key on like it should and everything works perfectly.
I used the VVT output pin and on the programable I/O page set it to on when FP_duty > 1.
The fuel pump primes on key on like it should and everything works perfectly.
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