help with short
Forum rules
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
help with short
I have an ms I processor with a v3 board and standard code. I had the ms working but when wiring the tps on the car I mistakenly connected the vref to the ground wire. now the ms will not work at all. The fuel pump light comes on and then goes out and it does not work at all on the stim. Any suggestions on what I shorted out?
-
Matt Cramer
- Super Squirter
- Posts: 2951
- Joined: Sat Jul 03, 2004 11:35 am
Re: help with short
To check for a short in the Megasquirt PCB, power up the Megasquirt on a Stimulator or on the car and check the following points for voltage with a multimeter.
You should find the same voltage as the battery voltage on the following points: S12, S12C, the center legs of Q9 and Q12, the left (non-banded) end of D3, the left leg of U5, and the left (banded) end of D9.
You should have 5 volts at the following points: S5, the two +5V holes in the proto area, the right (non-banded) end of D9, the right leg of U5, the left (banded) end of D19, and pins 1, 20, and 31 of the CPU.
Let me know where you find the correct voltages, and where you find the wrong ones.
You should find the same voltage as the battery voltage on the following points: S12, S12C, the center legs of Q9 and Q12, the left (non-banded) end of D3, the left leg of U5, and the left (banded) end of D9.
You should have 5 volts at the following points: S5, the two +5V holes in the proto area, the right (non-banded) end of D9, the right leg of U5, the left (banded) end of D19, and pins 1, 20, and 31 of the CPU.
Let me know where you find the correct voltages, and where you find the wrong ones.
Re: help with short
Thanks Matt
All the voltages are correct. I have noticed that d 19 has the same resistance in both directions. Could that be the culprit?
All the voltages are correct. I have noticed that d 19 has the same resistance in both directions. Could that be the culprit?
-
Matt Cramer
- Super Squirter
- Posts: 2951
- Joined: Sat Jul 03, 2004 11:35 am
Re: help with short
If D19 is bad, it will get hot and you'd see zero volts on most of the 5 volt plane.
Re: help with short
Matt
I reloaded firmware and now have communication. All gauages are functional on megatune except rpm and pulse width. Where do I go from here?
Thanks my friend
I reloaded firmware and now have communication. All gauages are functional on megatune except rpm and pulse width. Where do I go from here?
Thanks my friend
-
Matt Cramer
- Super Squirter
- Posts: 2951
- Joined: Sat Jul 03, 2004 11:35 am
Re: help with short
Get the RPM working. How is that input set up?
Re: help with short
Matt
I printed the pdf schematic of the v3 board. While checking the circuits at the u3 the ecu came alive and the stim is working. all guages are functional. Is there an issue with the opto isolator?
Thanks for the help so far
I printed the pdf schematic of the v3 board. While checking the circuits at the u3 the ecu came alive and the stim is working. all guages are functional. Is there an issue with the opto isolator?
Thanks for the help so far
Re: help with short
You can check the output of the opto-isolator with a 'scope or LED and resistor. The LED should flash like the Stim one. All the opto does is prevent high ignition volts getting to the processor under a fault condition. If you suspect the iso circuit you could try the VR one from the Stim.
Dave P, London UK.
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Re: help with short
got her up and running. started with first crank. now I have to fine tune the computer. Thanks for all your help. I started it with the l jet wiring and a pig tail I built. Now I will hook up the Diy harness all all the assundry sensors. You guys are great!