I have a problem I need help with. 1989 Si. When I try to start the car the ECU fuse in the engine bay blows evert time. Any sugestions? I would appreciate the help.

 

check for short anywhere in the main power section, that's about it,
I will need more info, what engine, have you done a swap, a obd 0 to obd1 conversion etc!!

 

u have a short somewhere.... if not the electrical load will be comming out.... check all the cables comming off the battt to the car.. intake isnt touching the pole. etc.. check the starter cables, and all that stuff... disconect the alternator, and lets se...

 

I'm not too sure about the wiring diagram of a Civic..

But basic Electrical Principles tells me that you don't have a Short Circuit.. What you do have is a Short to Ground, better known as a Grounded Circuit.

The reason why the fuse blows is because the battery is sending Current straight to Ground before the Load. And without the Load connected to the circuit, there is nothing to control the the amount of Current.

In plain English..... I believe there is an open in the wire after the Fuse and before the ECU, or whatever Load is on the circuit, that is allowing Current to dump straight to Ground and blow the Fuse..

THat's just what I think...

Good Luck..


[Modified by PnX-R, 9:38 PM 11/8/2002]

 

Godd lesson:

Now as a technician in Automation & control, I would say : Stop fuging up with the ignition switch, Each time you do it, you do a Critic load to you entire elecrical system, THis mean ECU( witch is protected by fuse) but it still receive ( like 0,5 seconde) the full curent of the batterie ( time that the fuse take over to burn).

Now as some One said, take the Live Wire, the one connected to the + pole, with this one disconected, hold it in your and and away from the batterie, Take a tester. with the red wire on the + ( on disconnected wire of Batterie ) and the Black on the - side of the batterie, check if the resistance betwenn the two wire of the tester is very low, if it is, this mean it's directed ground. If not it's an instrumentation ground.

Direct ground, look for main power wire, the one that juce up the starter or other Amp wire, or main cabin alimentaion wire having a LOW resistance with the - cable of the batterie.

instrumentation ground, look at eatch instrument for it's Alimentation then, look if it as a LOW resistance to ground (-) side of the batterie cable.

that'S about it the the Short Finding 101.




[Modified by kranked91dx, 6:46 AM 11/9/2002]