Trying to get rid of ECM

[TanZuk]

Don’t need the ECM any more with the new motor with the GSXR 4 carbs and the emissions are all eliminated..

The problem with the normal removal procedure is that doesn’t seem to be the fix for this Rig.

Here is the story with the ECM. When disassembly of the dash 2 years ago the ECM was removed. Needed to start the original motor but it would do anything. Plugged in the ECM and the ignition key switch buzzer started working and the dome like came on and the motor fired rite up.

This was not a fluke. Every time the motor started the ECM needed to be plugged in or it would not start. There was also another strange thing that was happening. When checking for a hot wires and the key turned on nothing was hot until the ECM was plugged in.

Being this was at the disassembly stage I didn’t worry about it because I thought there was a jumper wire needed when removing the ECM. I have found out that is not the case and the ECM should be removed without this happening. When the ECM is plugged in it there seems to be no issues with the electric.

Any ideas? Thanks for looking

[ScottieJ]

Hi Terry

We don't actually have ECMs in the European samurai wiring. Perhaps it might be worth comparing the two wiring diagrams, I would imagine the ECM gets powered up and then the ignition live feed etc. comes out of the ECM?
I'll try and get a chance to look through and work out how to bypass the ECM later.

These are the two you'll need, if you save them to your computer you can zoom in easily.

European (jap built)


US

[TanZuk]

Scott,

Thanks for the Euro wiring harness diagram. I have all ready got the US version.

I was looking at the diagram last night and it seems to be as you were mentioning. The ignition wire goes into the #13 pin on the ECM.

Everyone is telling me that all they do is unplug the ECM and everthing is good to go. This is not the case with this Zuk. Didn't know there was an issue until the ECM was unplugged during the dash removal a couple of years ago. Seems to work fine when the ECM was installed back then.

Really didn't know there was a problem because I thought there was probably a jumper wire that needed to be added to eliminate the ECM. Apperently the ECM should only needs to be removed and everything should work (Famous Last Words).

Not too concerned about it, if it can't be eliminated without a bunch of problems then the ECM will stay.

Thanks for the help though

[Darrell]

Well I must admit I've been through all that circuit diagram and cannot find out why it doesn't run with the ecm disconnected. I also cannot understand why the key buzzer doesn't work with it disconnected either as it does not link to the ecm at all. You say everything it dead with the ecm disconnected , it's almost like somebody has fitted a relay between the battery and the main circuit (energised by wire from the ecm) but why would anyone do that .
When you plug the ecm in, do you hear a click from anywhere (clutching at straws here )

[TanZuk]

Darrell,

Thanks for taking a look at the thread. Actually I'm still in the middle of the build and I haven't worked on the issue at all. I just found out that this was a problem recently when I was looking for a thread on how to remove the ECM.

After spending some time looking for some info with no results. I posted a couple of threads on a few other boards and the info that was passed on was that no one has a problem after just removing the ECM.

Probably will be getting to it in a coulpe of months. Really not that big of a deal for me. Just thought someone else may have had this issue. I always seem to have some strange thing happen that no one else does so this doesn't surprise me.

Believe the only thing that hasn't needed to be replaced or fixed is the headlights during the build.


If you would like to see what's going on with the build

Link

http://forum.suzukiclubuk.co.uk/vi ... 22/t,4427/

[Darrell]

O, I forgot to say. Your motor is a fantastic build . Makes most of ours look like a "hunk of junk"

[TanZuk]

O, I forgot to say. Your motor is a fantastic build . Makes most of ours look like a "hunk of junk"

Thanks Darrell for the complement. Not really trying to show up anyone with the pics this just happens to be the way that I build my projects. Hope that no one holds that against the build.

Just incase anyone was interested in the results of the problem. There seems to be an overwhelming agreement that the ECM is taking the place of a bad ground.

Have never been happy with the grounds that are scattered all over the Rig and had planned on doing something about this situation anyway. Just seems like these grounds are put where ever they decided to without much thought. I will probably soldier all the back grounds together to a larger gauge wire and have them all located in one spot on the rear of the frame. Follow the same steps in the front and add a couple of motor ground straps to the frame and body.

[Darrell]

Yes they could be correct. If the link wire number 5 is not connected to the body it could be possible that the cab has no earth and therefore no negative for the coil and most of the other circuits. It must have a good earth cable to the engine as it starts with the ecm connected. The ecm does show 2 earths one being the engine.
Does it still turn over with the ecm disconnected ?
Like you said a good cable from negative to body earth hopefully will sort it.
You could always just use a jump lead to try it.
If the ecm is providing the earth it won't have adequate diameter cables to handle the current when too many things are on IE: heater etc and may overheat.
Sorry for going on, I just need to understand how things work (or not as the case may be)

[TanZuk]

Darrell,

No problem nice to see that this interests you.

OK, the problems that I had mentioned was something that I had noitced when working on disasembly of the dash 2 years ago. Haven't done any trouibleshooting yet because it is not the next thing on the list yet. I will just be using the engine stand wiring just to keep the motor running for now.

From what I remember from back then there was no juice going to anything without the ECM connected.

Things that didn't work that I noticed:

No juice to the starter
No juice to the ignition switch
Key buzzer not working
Dome light not working.

When plugging in the ECM all this started working.

Remember that the dash was taken out and wires hanging everywhere and there was also a front US PS front fender removed at the time. The motor was still in to move it around.

So things were a bit of a mess