Mark's build diary

[daydreamer]

Hi Mark,

Are you using the donor ECU or an aftermarket ECU ?

If you're using the donor ECU then I think you may have cut at the wrong place. At least joining the wires back up to the original should be straight forward.

I can suggest these "Solder sleeve butt splices" for joining the wires back up.

www.vehicle-wiring-products.eu/VWP-onlinestore/terminalspreins/heatsealterms.php

I've used them quite a lot and added glue lined heatshrink over the top as the odd stray wire can poke through if your not careful. I use a diy paint stripper heat gun with a fine nozzle to heat them up.

www.heatshrink-online.co.uk/heatshrink/cat_146271--001-31-AdhesiveGlue-Lined-Heatshrink.html

As the Beeb likes to say " other suppliers are available."

[markharnett]

I've been thinking about it and I might be alright. I'm sure I cut the connector in the picture off the loom with the fuse box on it. After looking really hard at the pics in the build guide, the engine loom has the ECU on it right?

So I think I cut the other side of the connector off, so I might be alright!

Next question is though, what goes into the connector that in the pic that I thought was C80?

I am using the Omex 600 with the Omex loom. This appears to have connectors for the injectors etc, so do I remove the small loom that came already attached to the engine?

Cheers
Mark

[airforceone]

Mark

I have the Omex loom as well, I completely removed the engine loom. I do however have the fully
wired loom with the connections attached. SO basically connects from the ECU to all the injectors
the TPS, CPS, Idle motor, CTS, coil and Lambda sensor.

Ned.

[markharnett]

Cheers Ned,

I think I have that as well, so have to do the same.

Do you have that small grey box by the distributor on yours?

Cheers
Mark

[airforceone]

No, don't have that either. Luckily the Omex loom has all the connections required and I have
Connected all of them, so that small grey box can't be needed by the ecu.

I can take some pics when I get home tonight if you need any.

Ned

[markharnett]

That would be great if you don't mind Ned. I just need to get my head round how it all goes together and pics will help!

Thanks
Mark

[markharnett]

I've been tinkering with the electrics tonight and think I have more or less got there with Neds help!

I'll post some comprehensive pics of my setup with the Omex 600 ECU and loom once I have it sorted, which will hopefully help others.

I do have a question in the tech section on the diagnostic connector, so if you could take a look and shed some light that would be great:

www.mevowners.proboards.com/index.cgi?action=display&board=electrics&thread=2537&page=1#19020

Cheers
Mark

[ncohen]

I look forward to seeing that as no doubt I will be in the same boat as you with that lol

Great work!

[markharnett]

Hi All,

What do you make of this diagram. I have the Omex ECU and loom. There is a power relay on that loom and not 100% sure how this wires up without looking at it (It's in the workshop at the mo!) hence the question mark.

All thoughts welcome!

I HAVE REMOVED THIS PIC AS I THINK IT IS INCORRECT AND DO NOT WANT TO CONFUSE PEOPLE!!

Please see updated pic in thread below

[markharnett]

might be a slight issue in the above with the fan relay. From what I have read it appears that the ECU connection is the earth point, so the other side hase to go to a switched live.

Maybe that is the same for the fuel pump as well?

[ollieballs]

thin red wire from the omex relay goes to ignition source, thick red to battery permanant via a 1 or 3 amp fuse, anything switched by the omex ecu is on an earthing switch rather than a powered switch so power has to come from somewhere else. which means that the diagram of your fan relay there is wrong. the power would come from the other side of the coil, through the coil and earth through the omex ecu. i believe the pre made harness accomodates for both sides of the coil on the fuel pump relay though although dont make the same mistake i did and wire 2 relays in series on the fuel pumps! (if you have a swirl pot system) took me ages to work out that gremlin! hope this helps

[ollieballs]

also i see you have the fuses on the eath side of the componants here.. whenever i buy new componants they always say to fuse the wire as close to the source as possible so that any serge is localised between the battery positive and the fuse rather than at any point along the wire (or even in the componant!) making it much more dificult to find. id say thats pretty important. ive got all my fuses either wired from my main fuse (and main fuse back to battery) or on the ignition source off my main relay (if the fused componant is ignition fed) also VERY interesting to note... CARBON FIBER CONDUCTS ELECTRICITY!!!! scared the living daylights out of me when a live wire landed on a carbon panel of mine.. lots of smoke and lightning! be warned!
are you wiring in a battery kill switch?

[markharnett]

Hi Ollie,

Thanks for the reply!

It makes a bit more sense about the ECU being the earth points now. I have modified the diagram to have the power to the fuel and fan relay coming from the main relay, so when the ignition is switched on they get power. The earth then goes to the ECU, so they only flick on when the ECU earths them. I think that is right?

Also, I currently have the ECU perm feed going through a 10amp fuse. I take it that it is that fuse that needs to be changed to a 1amp?

Also, the fuses being on the earth side is just another small mistake in the diagram. I meant to have them coming from the positive feed.

Thanks for the info. I'm going to amend the diagram and I'll post it back up. I'll remove the old one as well so others don't get confused!

Cheers
Mark

[markharnett]

Ok, so here is an updated diagram.....I think I am getting closer, but still not 100% sure (I did find some free software for doing electrical diagrams though! It's called TinyCAD):

[ollieballs]

hey mark,
i couldnt personally find a 1a fuse in any auto shop so i bunged a 3a one in.. close enough.. but yeah 10 amp is a little high considering how easy ecu's are to fry. i would also consider completing the wiring to the ecu before powering it up to test it.. you never know how they will react if there is no signal or a loose wire earths. expensive mistakes easy to avoid at the end of the day