Faulty Injector Circuit ( was "Problem I cant Solve&quo

ramon alban · Post by **ramon alban** » Sun May 27, 2007 8:40 am

To V8 Mini

Ive taken the liberty of starting a new thread. It's best to keep individual problems separate, I think.

V8 Mini wrote:some things sound simular to what i've been trying to sort out on my Mini.

it wouldnt start on friday, so i left it to sort out today, and first thing i found was all cylinders where full of fuel, so i cranked it over without plugs to pump it out (goes quite far almost got the neighbours car across the road). left it to dry out whilst checking injection system out. i did notice some injectors were not closing properly, so fitted a spare set i had of ebay a while back, that had been ultasonicly cleaned (supposidly).

all seemed ok, and it started, ran a bit rougth, after a bit it died and wouldnt start again. injectors appered to all be open again, plugs were quite wet. i went over this a few times, problem would seem to go away, but would soon return.
before packing up, last try, almost starts then nothing. as i turn the ignition on i notice all injectors click (open?) and also click again when ignition is turned off (closed?). plus i also noticed the resistor pack was quite hot.
iv'e check the resistor pack and injector cuircuits and all reads ok.
any ideas?

maybe it time i got that mega squirt

The logical cause of your problem where fuel flows continuously and the resistor pack is hot, is that the ECU has broken.

The ECU output transistor(s) that switch 4 or 8 injectors on and off have gone short circuit.

Try a substitute ECU and the fault should disappear.

Alternatively you have a short circuit in the wiring going to the ECU that is earthing 4 or 8 injectors continuously.

Either way you can verify the injectors and associated wiring using the PDF available from here.

http://www.vintagemodelairplane.com/pag ... tor01.html

Out of interest there are several other component descriptions here:

http://www.vintagemodelairplane.com/pag ... nts01.html

V8 Mini · Post by **V8 Mini** » Sun May 27, 2007 1:50 pm

one extra thing i have discovered concering the ECU is that last week before these problems started i fitted a new radiator, and on filling and bleading the cooling system some coolant did get thrown out of the header tank near the ECU. i have taken the cover off the ECU and although the curcuit board looks dry and no damage from wet, there was traces of coolant on the inside of the cover.

so i'm assuming at some point coolant might have got onto the ECU curcuit and has caused some damage.

i've been think of getting a Megasquirt for a while now, and think this might be the ideal time to change.

ramon alban · Post by **ramon alban** » Sun May 27, 2007 3:09 pm

V8 Mini wrote:one extra thing i have discovered concering the ECU is that last week before these problems started i fitted a new radiator, and on filling and bleading the cooling system some coolant did get thrown out of the header tank near the ECU. i have taken the cover off the ECU and although the curcuit board looks dry and no damage from wet, there was traces of coolant on the inside of the cover.

so i'm assuming at some point coolant might have got onto the ECU curcuit and has caused some damage.

i've been think of getting a Megasquirt for a while now, and think this might be the ideal time to change.

You did ask for ideas and it could make a difference, the ECU getting wet??

Anyway, here's another one.

This item went for £5 on ebay and many others go for less than 30 quid.

http://cgi.ebay.co.uk/range-rover-ecu-1 ... dZViewItem

and if you read this you will see that early Range Rover ECU's can be persuaded to run in SD1 systems.

http://www.vintagemodelairplane.com/pag ... ECU01.html

V8 Mini · Post by **V8 Mini** » Sun May 27, 2007 6:50 pm

it was an after thought to check that, but it had been running for most of the week before the problems started.
although the boards looked dry, there was a few drops on the inside cover, so i can only assume the boards had been wet at some point.

the loom is also very hard and brittle, so it could also be in that, or a combination of the two.

i have sent an enquiry to Phil for a megasuirt ECU, i think now is the time to ditch the old items and start with a fresh loom