Simplifying A Gti-6 Loom

[[L'e$kro] 2]

Hi all

I'm actually looking for a way to replace my Megasquirt loom + ECU by a standard Gti-6 unlocked ECU + loom in my phase 1 205 gti

Then I'll make a patch loom to run the Megasquirt on the 55 pin connector. Reason: be able to use the car if I have to troubleshoot the Megasquirt

 

Here is the question: what sensors/features can be removed without having the ECU going into "safe mode": go home without power mode?

For example I don't have the ability to run the idle control valve on my modified manifold (its been blanked off), so I'd like to see it go

I was thinking as well to remove the throttle body heater

 

My car setup right now is exactely like the Megasquirt 2 diagram:

My car being a phase 1, sensors for the dashboard are connected by a different loom than the ECU one

I also replaced the double relay behind the left light by 2 standard relays + fuses

Do you think I can rewire the gti-6 loom without its relay + unnecessary sensors

 

If anybody has inputs on this, I'd be glad!

 

Thanks in advance,

 

Nicolas

Edited September 22, 2009 by [L'e$kro]

[welshpug 1,622]

I doubt it will idle without the ICV, never heard of a "safe mode" from on of these ecu's, though I think they do have a base setting if they get no input from a sensor.

 

t/b heater can go without issue I would imagine, though it depends how cold it gets where you are over the winter.

[[L'e$kro] 2]

Thank you for your reply Welshpug

 

I doubt it will idle without the ICV

 

on 8v turbo engines french 205 drivers often ditch the ICV without issues. I'd like to do the same thing on my Xu10j4rs.

On the throttle body, there is a screw which manually sets the idle (=prevents the butterfly from closing)

I'll probably end with an Idle slightly higher once warm, but shouldn't be an issue though

 

never heard of a "safe mode" from on of these ecu's, though I think they do have a base setting if they get no input from a sensor.

 

I'm not sure there is a "safe mode" either, but I've heard about this for other ECUs (Bosch probably), so I "assumed" it was a general thing with OE ECUs

 

t/b heater can go without issue I would imagine, though it depends how cold it gets where you are over the winter.

 

I actually never seen any throttle body frozen?

Anyway if it happens one day to be that cold in Cork City I'll be more concerned about the grip and will probably end taking the bus

 

Thanks again for your answer

Nicolas

[[L'e$kro] 2]

Hello

I've removed from the GTi-6 loom so far:

 

-Canister Purge Valve

-Inertia fuel shutoff

-Immobilizer Control Module

-Instrument Panel

-Data Link Connector

-Air-con

-Throttle Body Heater

-Steering Pressure Switch

-Idle Air Control Valve

 

 

Do you think it may work like this? Will it work without immobilizer wires??

 

Regards

 

Nicolas

[welshpug 1,622]

yes, should work fine though may store faults for Canister purge valve and throttle body heater.

 

I would personally keep the DLC.

[[L'e$kro] 2]

And I also removed from the loom the double relay:

 

I'd like to run the gti-6 ECU like the megasquirt one:

 

I have replaced the 2 relays in my phase 1 gti by 2 simple relays to follow the MS2 v3 wiring diagram

( http://www.megamanual.com/ms2/v3ext_wiring.gif )

 

The 2 relays are connected to fuses to protect the whole thing

 

ECU, Injectors and ignition are fed by the main relay when switching the key ON

 

Then when the engine is cranking, the ECU "grounds" the fuel pump relay to turn the fuel pump ON

 

I'd like to use this existing setup but I'm not to sure about what pin is what on the ECU, so I'd like more infos on those, if you have any:

 

ECU pin 7

ECU pin 35

ECU pin 52

ECU pin 13

 

I'll dif a bit in autodata on my side, but if anybody has a clue about what I'd like to do...

 

Basically what I'm looking is:

-what wire is feeding the ECU?

-What wire can I use to ground the fuel pump relay when cranking?

 

Thanks!

 

Nicolas

[[L'e$kro] 2]

yes, should work fine though may store faults for Canister purge valve and throttle body heater.

 

I would personally keep the DLC.

-The throttle body heater is not connected to the ECU, it's just connected to the +12V relay, so won't be a problem apparently

-For the canister purge valve I may use a resistor, as written in another post somewhere.

-You are right about the Data Link Connector, it may be useful. I didn't cut anything from the ECU connector, I removed the pins properly so I will add this back once the car is running

 

 

Thanks for the input Welshpug, I think I'm moving in the good way

 

Nicolas

[Miles 331 1 Cars]

Removing the TB heater isn;t a issue as said, I ditch all of mine too

[[L'e$kro] 2]

Hello

Thank you Miles for confirmation.

 

I checked in Autodata and found this (may not be displayed like this)

Pin#               Type                            Condition
35                 Input Signal                    Ign On
52                 ECM Switched earth              Engine On or running
48                 12V                             Ign On
27                 12V                             Ign On
7                  ECM switched Earth              Ign On (12V)
                                                  Engine Cranking - 0V
13                 Input Signal (12V)

 

 

It looks like pin #7 is not appropriate as a Fuel pump relay ground as it gives +12V when ignition is On but engine not running

 

Nicolas

Edited October 4, 2009 by [L'e$kro]

[[L'e$kro] 2]

I grounded the fuel pump relay myself, to see if it would start

When I turn the key I now can hear the fuel pump running, but it wont start

 

So now my focus is: how is the ECU fed in 12V?

Is there any way to know that the ECU is running?

 

Cheers

 

Nicolas

[[L'e$kro] 2]

No answers?

Well I partially found the answer

I found a pin to feed the ECU with switched live: pin #13

 

The car now works without the double relay, although I didn't plug a few things yet (map sensor, knock sensor, lambda sensor and speed sensor). I'll add them soon.

 

However I wasn't able to find any earth pin which switches when car is running, like on the megasquirt or on the 205 gti ecu...

 

I tried pins 7 and 52, but both provide ground even when engine is not cranking, so not much help in case of accident

 

If you have any idea on this, let me know

 

Regards,

 

Nicolas

[pug_ham 240 3 Cars]

' date='Oct 5 2009, 11:31 AM' post='994094']I grounded the fuel pump relay myself, to see if it would start

When I turn the key I now can hear the fuel pump running, but it wont start

 

So now my focus is: how is the ECU fed in 12V?

Is there any way to know that the ECU is running?

I would've suggested checking if you have a spark & are the injectors firing but now you've got it running you must've found your fault although you really want to keep the double relay in the loom imo. If you have a spark then the ecu is working.

 

The ecu is fed 12v from the same pin on the alternator which is connected directly to the battery, other than that from looking on autodata the ecu pins that are permanent earths are 17 & 36, pins 7 & 52 go to the double relay & should be ecm switched earths.

 

Graham.

[[L'e$kro] 2]

I would've suggested checking if you have a spark & are the injectors firing but now you've got it running you must've found your fault although you really want to keep the double relay in the loom imo. If you have a spark then the ecu is working.

 

The ecu is fed 12v from the same pin on the alternator which is connected directly to the battery, other than that from looking on autodata the ecu pins that are permanent earths are 17 & 36, pins 7 & 52 go to the double relay & should be ecm switched earths.

 

Graham..

 

Thanks Graham for your reply

I basically wanted to get rid of the double relay, as it was redundant with the 2 single ones installed during my previous Megasquirt install (1 main relay triggered by ignition, and a Fuel Pump one triggered by ECU)

I want to make a simple loom just from the ECU to strictly needed sensors/injectors/coils.

Then later on I'll probably put a Megasquirt-based ECU with 55pin connector on my 306 simplified loom, so I need to know what is what...

 

Long story short here is what I did in details:

Without the double relay it wouldn't start, so I put it back and the car started. It appeared that the needed wire was pin #13, so I presume this one is the ECU feed

 

Then I connected injectors, pin #13 and coils to my main relay, and could remove the double relay from the loom...

Now remains only the question, how to trigger the fuel pump relay from the ECU, as both the #7 and #52 do not seem up to the job as they switch as soon as ECU is fed from #13

 

Anyway I'm quite happy like this, and I spent the last 2 nights rewiring everything to put the ECU in the glovebox (LHD gti)

 

Thanks for reading, hope it might help others!

 

Nicolas