3b ecu fuse blowing? advice needed.

[Quattro Dan.]

I have a 3b that ran fine yesterday but has a flat battery so i put it on charge and turned it over but it would not start. Checked the 2 ecu (motor) fuses at hte front of the fuse box and found the right had side one had blown. I have replaced it with a new fuse but it keeps blowing. Anyone know any reason why this is happening?

Thanks in advance.

[spink]

I have a 3b that ran fine yesterday but has a flat battery so i put it on charge and turned it over but it would not start. Checked the 2 ecu (motor) fuses at hte front of the fuse box and found the right had side one had blown. I have replaced it with a new fuse but it keeps blowing. Anyone know any reason why this is happening?

Thanks in advance.

alright Dan,I have come across this twice,both times the ecu had blown causing the fuse to blow as soon as it connected,have you got a spare ecu kicking about?

[Tonks4x4]

Is the ECU out of the blue S2 reg H880 ?

Of so take the ECU lid off and check that there is not one of the components shorting out near the plug pins

[UrS4boy]

I have a 3b that ran fine yesterday but has a flat battery so i put it on charge and turned it over but it would not start. Checked the 2 ecu (motor) fuses at the front of the fuse box and found the right side one had blown. I have replaced it with a new fuse but it keeps blowing. Anyone know any reason why this is happening? Thanks in advance.

According to Paul N's diagrams (pg.43/57), on the row with the No. 23 through 32 fuse holders, the No. 23, 26 and 30 holder positions are empty, with No. 24 = the ISV, WGFV and Evap Control fuse, No. 25 the O2 sensor fuse, No. 27 = ECU constant 12v, No. 28 = fuel injectors and MAF and No. 32 = coils (reference: Paul's wiring pdf, Pg. 40/57)

The two motor fuses are 27 and 28, with 28 on the right side. So you must have a dead short in either the injectors, the MAF or the wires between the ECU and these devices. It won't be easy but you need to check them out methodically. Good luck.

[Quattro Dan.]

Is the ECU out of the blue S2 reg H880 ?

Of so take the ECU lid off and check that there is not one of the components shorting out near the plug pins

Thanks for the reply Brian, no it is not H880s ecu.