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A P259 spoiled my install

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Sprocket:
I still use the p259 to drive relays, but I made sure right from the very start that the relays are internally flyback protected, and as it happens, the Rover relay pack is, as are all the individual Siemens relays (yellow). Tyco manufacture an almost identical relay http://www.tycoelectronics.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Data+Sheet%7FV23134-X0000-A001%7FG%7Fpdf%7FEnglish%7FENG_DS_V23134-X0000-A001_G.pdf

It must be simple enough to introduce a flyback circuit for each channel onboard? I understand the reverse voltage thing is bad, but then that is down to the way the grounding is externaly connected. Could this not be done internally too? And while we are at it, many OEM ECUs have individual sensor grounds for each sensor, connecting to their own pins, which leads to the need for more pins. Some of you may have seen this before, but I'll show it again. I butchered my front plate and instead of fitting an EC18, I fitted another EC36. Spacing was tight and off center, with the original 18 pins in the middle, and the others around them. Used for internaly wired options. It would mean a redesign of the board layout, but it doesnt look a major problem to implement this. The only real issue is crossing over the loom connectors. I got round this by using a Red EC36 connector from Rover which has a different gender. I had to rob it from a loom. I wanted to use the matching EC36 ECU connector, but at the time I could not bring myself to buy an expencive OEM ECu just for the connector, so I just glued a piece of plastic onto the connector and cut the other one off, to change its gender. I dont suggest you try this on a built ECU, as I damaged one board trying this, so built the next one with this from the start.

multiplex:
wow i like the idea of 2 36 pin connectors!

i blew my p259 but it was many many years ago  ;D. i attempted to replace the chip, but still never regained functionality.

i've managed to survive on stepper, inj & ign.

MWfire:
i use p259 for rpms(90% of instalation), relay for fuel pump (95% of instalation), relay for N20, relay for fan, relay for water injection.... So far i didn't fry any p259(instaled more than 20) and i use all types of relays ...
Maybee is problem in GND?

GintsK:
I usually do same as MWfire. With three relays hooked + tacho it works.
Most often P259 becomes fried during incautious installation procedure.
Main P259 weakness is internal ground connection.

What can be wrong in solution when both grounds are connected inside ECU versus recommended solution to connect both grounds 15cm from ECU??

[email protected]:
The 15cm separation is to ensure that the voltage rise on the grounds is factored in to the A2D.  When the grounds are coping with several overlapping injector and coil events the voltage rise a few mV - this is likey to effect the sensor readings which are very discrete.

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