Dave Henshall

does anybody else notice this.... or is this the root of my problems...?

when the batery has been disconnected for some time (a week or so) when its been in storage/ repair, wheni reconnect it, then turn the ignition key, neither the fuel pump or ISCV operates for about 30 seconds. once it has run, they work straight away.


i'm thinking that this may be linked with its cutting out problem. the ignition relays drop out (momentatily) causing the car to miss. it is defo the relays, ive had a multimeter on them and its not the live side that is the problem. its the switched earth side - which surprise surpirse is routed through the ecu. had anyone else had anything similar - ive heard of P8 syndrome - have i got it...?

DazC

iTrader: (1)

P8 syndrome is where the ECU drops in and out of limp home mode for no reason...moody ECU...obviously female.

Is the ECU at fault or is it something the ECU is sensing and is cutting the fuel pump off momentarily?

Dave Henshall

i know that if i go from the live side of the relays to earth, they are at a good 12 volts all the time. when the relays click out/in again the voltage does not budge on the live side which point to the earthing through the ecu. the earths have all been cleaned and checked and are around 0.3 ohms.


when it goes into limp mode..... it still runs but at reduced boost i take it... and then it comes back after seveal seconds once you have let it idle for a few seconds... this sounds familiar, ...

DazC

iTrader: (1)

Won't rev past 4k in limp home..... I assume it will only run limited boost as well.

The ECU controls the earth....they don't just go through it. If the ECU doesn't have all the right signals from all the sensors it can drop the earth as soon as it sees a problem.

Dave Henshall

thats what its doing - i know the ecu switches the earths - but does anyone know whatr happens when it swaps from normal to limp - does the ecu stop/start itself - which would explain the probs im having?

DazC

iTrader: (1)

You need to ask Stu @ Motorsport Developments mate. He knows shite loads about the Marrelli ECU's.

I can't help you anymore unfortunately.