2G No power to ecu. HELP!

[gsxgota]

i was driving my 2g gsx home last night, and it died on me, everything was running execpt the engine. no rpms, it dies like this sometimes but it always starts back up. After pushing my car home, i saw that my afc had now power. So i thought the afc had a loose wire or something, after double checking everything, everthing seemed fine. but it didnt do the trick, In the Morning when i had some light, i checked everything out. It seemed like i had no power to the ECU, So i checked the Engine Moture 20a fuse, and it was blown, so i replace it, and everytime i put a new fuse in and turned the ignition, it blew. i went though a few fuses, So i need your guys inupt on this, is something wrong with my ecu, or is there is short somewhere, and if so, how would i go about finding it? thanks
adam

 

[Maxximillion]

well to diagnose a problem, we need some info like do you have a remote starter or an aftermarket alarm installed. did you ever get a check engine light? and will the fuse blow if you just put your key to ON? or does it do it blow you try to crank it.

if you think its the ECU, try to see if you get a heartbeat from it, meaning go under your driver side dash and look to the right of your fuse box and you should see a harness with a black rubber cover on it. if there is no cover, then you should be seeing a white harness with about 4 or 5 exposed pins. this is your diagnostic port for your ECU.

now to check to see if the ECU is working or if it has stored any codes, you will need an analog volt meter, meaning a volt meter with a needle, not a digital one. with the volt meter take one of the probes and place it on the top left pin of the diagnostic port, and with the other probe place it on the bottom right pin of the port. turn your key to ON if you can and watch for any needle sweeps. and count them.

if the needle of the volt meter just keeps sweeping back and forth and no pausing then your ECU is working and it hasn't stored any trouble codes, "the heartbeat of a DSM." but if it is pausing then count the sweeps in between longer pauses. I.E. if the needle sweeps twice then pause, and then 3 times and pause then it would be code "23" the code should keep repeating until it is reset by the disconnecting the battery.

if it did throw you a code then look in a chilton or haynes book to see what that code means. but i doubt it gave you one so i would just look to see if your ECU is fried. by looking for that "heartbeat". next i would check for aftermarket installs of alarms or remote starters as it has a direct impact on that fuse from the battery. and by the way that 20a fuse is your MPI relay fuse. it provides power to the MPI relay to control power to the ECU, fuel injectors and your fuel pump. the relay has constant power so there might be something messed up with the relay itself which is what i would look to check first. if you have a chilton or haynes book it will take you through the process in which to check the relay to make sure it is working okay. if you don't have a book i highly suggest to go get one. they are only about 20 dollars canadian and they are a very good investment for a DSM owner. if you don't have one i can explain the steps to check the relay, and there are other things to try as well but one step at a time.

let me know what you find.
Jason.

 

[gsxgota]

i just fixed the problem. after going though all the wiring, and testing, i decided to try and change the mfi relay. and that fixed it!

 

[steve]

Let me know what you find.
Jason.

Jason, this is good stuff but you should be aware that 1G's are quite different from 2G's even when we are talking about 4g63 based 2G's. The 420a 2G are so different as to be another animal. So, what you posted would be useful suggestions for somebody with a 1G it's not even close for a 2G.

Steve