Blown trigger hardware??

[Arthur]

Hi all

I'm very comfused about an general problem I have now.

A month ago I transfered to an ather inlet header and I redesigd some things. Three weaks ago I blew up the to fets off my idle pmw.

Even the copper came losse from the board. This is the first thing. How can that happen when the whole computer is fused 10A

I drove home with 3000rmp idle with the burned fets so the rest of the board seemed oké. Now I soldered new fets in the last two injfet channals I had left and now I suddenly can't get a trigger signal. 

I cheeked the trigger sensor with an other and maesured the resitance off the threds. (even on the board)

It really looks the trigger hardware fried to, but how can it have worked the last time I drove home?

Why is it that everytime I repair something, something else seems to break. 

Can I measure the trigger hardware to make sure I'ts broke?

[GintsK]

Fuse for ECU do not protect FETs from over-current. For this purpose fuse should be in FET driven circuit.

Most often problem when no triggering occurs is described here:
http://195.159.109.134/vemsuk/forum/index.php/topic,676.0.html

Gints

[mattias]

The ECU only draws a couple of 100-200 mA. You must use separate fuses for everything that is grounded through the ECU.

[Arthur]

oops

I knew that. The genboard only makes ground. I now fused the pwm with 5A separately. The only thing that is strange is that I stopped a running car three weeks ago and now no triggering. I don,t even see 300rmp cranking speed. Can cold wether/snow have something to do  with it?

In that link it seems the p259 acts as a "gateway" for the trigger signal? In my config the fuelpump and ignision only where switched on via relay (by p259) while cranking and running. So no trigger signal ment no v+ to coil and fuelpump.

And I used rob's guide for the gounding. Even with extra's. All grounds twisted togetter, than five cables go to main gound point and are twisted again in one single ... "round put on your stud thingy"

O. One other thing. I put the battery in the boot some time ago. It did run afterwards thou.

[Arthur]

Hi guys

Gess what. I cut the 21th pin off the p259 and it triggers again. So problem solved still confused

How could it have run without trigger? Perhaps it what he last heroic deed.

[mattias]

The P259 slowly broke down, in the end it consumes all of the current the little +5V regulator can produce, and the trigger circuitry will not work at that point as it depends on the current from the same voltage regulator.
When you cut the pin on the P259 it won't drain all the current anymore and the other things start working again.

Yes, the P259 is a picky little circuit and should be used with care. All relays you drive with it should have diode protection against flyback voltage, if they don't - add one externally.

[Arthur]

Oké

I'll check that.