How do you take the big ECU plug apart? I've taken off the small cable tie, but can't see what happens next?

 

I need to add a wire for the EGR valve for my AFH conversion, but its the same ECU and plug so probably of interest to the general crew searching for answers?

The hood is on little plastic lugs and it just pops off, on some of the marelli and Bosch ecus you need to remove the slider part too to acess the terminal release mechanism but If I recall you don't need to on those. Be carefull, it's almost impossible to remove the terminal without the proper release tool without chewing up the plastic housing. I've got a set of those terminal tools.

Further to this, I'm ashamed to say I can't remember which pin is for the egr valve, one wire goes to the fuel pump relay live terminal which is easy to find in the loom because it has a splice where all the fuel injectors come off it, only one wire needs to go back to the ecu plug which is in effect the negative connection for the solenoid... ie the positive side is constantly on whenever the fuel pump relay is on, the ecu switches the other wire to ground to activate the solenoid, it's a pwm signal of around 100hz if I recall, the frequency is constant it's just the pulse width that alters.. My memory is a bit rusty on the PIN number I'm going to have to read up on my previous postings to find it.

Thanks Tom,

 

To save you looking I think you said: 

 

"the egr plug was chopped from the 16v polo loom, black wire with white tracer goes to switched live via loom, purple wire goes to ecu pin 5"

Ah ok yes... That'll be it then. It's not a switched live per se, it doesn't make a lot of odds where the live comes from but it makes more sense to take it from the fuel pump relay live, it's easy to find, there's a thick red wire that goes into a splice (joint) and a few wires come out of it some of which go to the fuel injectors, make a decent job of splicing it though otherwise it will cause you headaches in time to come, I've got some really good heat shrinkable solder splice connectors which are prefect for that, you strip the ends off the wire slide them in, then heat it with a hot air gun and it shrinks and solders it in one shot, and it's waterproof too.

So is it possible to insert an additional terminal perhaps without damage but removal is the problem? I have two ecu plugs and don't need them both so destructive removal isn't really an issue?

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Yes the terminals just click into place, it's removing them that is the difficult job