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changing gear is over rated
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Discussion Starter · #1 ·
Just built up my DIYPNP, it connects fine & have put a base map on it from my laptop. BUT when I plug it into the cars loom I cannot connect to it. I am using tunerstudio, comms settings okay on mains power, but not on the cars 12v, when I crank the engine I get comms for a second or two before the screen greys again & not connected message appears.

I have checked the 12v from the loom and that is okay (12v, 10.5v when cranking) I have checked the same on the main board of the MS board and get the same voltages. Also getting good earths on the mainboard and the loom plug.

Basically can connect on mains, but not on the cars 12v, despite always getting 12v at the mainboard
Any ideas folks?
 

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sounds like wiring to me.
Double check you are are getting the 12v power with ignition on at the pin you should be.. and that you've wired that pin over correctly inside the case.

also check your earths in the same ways.

Sounds almost like you have 12v only at cranking.
 

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changing gear is over rated
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deffo getting the 12v to the correct pin on the main board (not measuring at the adaptor board) at all times, thats what baffles me. Wish the board had an led to confirm there is power to the board somewhere
 

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Happily expanding the To Do list since 1997
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Just for clarity: Are you saying it's just the serial link that's not working? Do you mean the engine starts and runs?
 

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changing gear is over rated
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1,703 Posts
Discussion Starter · #6 ·
can't say, not setup the sensors so haven't started cranking etc yet.

Just playing now, my ecu pinout is like this:


If I leave the mains power & the "2" block in i can still see the ecu, but as soon as I connect the "1" block it disconnects.

Just gone over the board with a multimeter again and it seems okay from the 12v & -ve point of view.

Any idea what sensors should be getting 12v from the ECU?
 

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Definateley sounds like a wiring issue. From the diagram you've got 12v on one block and your grounds on another. Not sure how you're getting power if only one is plugged in.

Do your wire colours match with the diagram?
 

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can't say, not setup the sensors so haven't started cranking etc yet.

Just playing now, my ecu pinout is like this:


If I leave the mains power & the "2" block in i can still see the ecu, but as soon as I connect the "1" block it disconnects.

Just gone over the board with a multimeter again and it seems okay from the 12v & -ve point of view.

Any idea what sensors should be getting 12v from the ECU?
You have got the connections the right way around haven't you? i.e. you've not accidently put 12V to 1A instead?!
 

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changing gear is over rated
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Discussion Starter · #11 ·
nope, checked that.

okay just resoldered all the connections from the adaptor board to the main board and the D9 socket. Plugged in the car and connected okay, cranked and saw 250rpm then it dropped connection and won't reconnect at all. Go on to 12v mains and all okay.


suggestions?
 

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right so it connects on ignition but not cranking?
If so try closing tunerstudio or megatune and then reopen it.. i've found sometimes its the usb/serial link gets dropped cranking (or ecu power cycles) and it doesnt recover without closing and reopening the software.
 

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changing gear is over rated
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Discussion Starter · #13 ·
no, not that, seems to trip out something & wont connect, only reconnects when I unplug ecu/loom/laptop and reconnect, then does the same. Points to a wiring fault but don't know where as after it has tripped out & I cannot connect I still see 12v power to the mainboard
 

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changing gear is over rated
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Discussion Starter · #14 ·
decided I will run just the 12v & ground from the loom to the ecu to see if I have a wiring fault elsewhere causing my issues, with just power from the car & no sensors etc attached, see what happens then.
 

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decided I will run just the 12v & ground from the loom to the ecu to see if I have a wiring fault elsewhere causing my issues, with just power from the car & no sensors etc attached, see what happens then.
You have a short!!! Unplug your TPS and I bet everything works. This is because you ran the VREF wire, which you don't do with a stock TPS, manual trans, 1.6.
 

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see it pays to have a pro no here

plenty of us know alot but them what work with them all day every day really are helpful
 
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