diesel FAS kill switch

[groar]

short story : it works and here is a little video taken during a static test : mov00011.mp4(*)

You can see :

• the RPM on the right,
• the heat plugs light at the upper right,
• the airbag light at the upper left,
• the low fuel light at the lower left.

Time line :

• 00:03 : the engine starts
• 00:07 : the kill switch kills the engine
• 00:10 : the kill switch is put back on

I let you imagine how I did that. I should be able to take pictures tomorrow

Have fun,

Denis.

(*) on the video the trip odo is at 1696.9km (1054.6mi). Now the trip odo is at 1763.3km (1095.7mi, which is my longest tank ) and the FAS kill switch works very well

[ConnClark]

My injector pump already shuts off all fuel to the engine when I take my foot off the accelerator when the rpms are over 1000.

[groar]

The goal is to be able to FAS (Force Auto Stop, ie stop the engine) while in neutral without touching the key, ie without having to switch off/on the ECU.

The engine doesn't consume fuel when you remove your right foot only when you are in engine brake, so not in neutral.

With engine break your car is slowing down very fast compared to neutral, noticeably when your car is aeromodded and with tires pumped up to max side wall.

Have fun,

Denis.

[groar]

To do my kill switch I decided to put a switch on a cable connected to the stop solenoid.

On a diesel the stop solenoid permits to stop the diesel flow else the engine would continue to run... That happened to me a few months ago when the stop solenoid got blocked so I had to make the engine stall to stop it. It's strange to hear the engine to continue to run while your car is switched off without any key in it. Sadly the solenoid is inside an anti-thief box which have to be broken to be able to repair the solenoid : cost, cost, cost...

First I took a revue for my car :


I found the electric diagram :

Damned, why did I never took any electricity/electronic option at school ?

I located the stop solenoid on it (#22 on the center of the photo) :


So decided to put the switch on cables #384, #382 or #383.

So first step is to open the engine compartment :

Damned, why did I never took any mechanical option at school ?

then open the fuse compartment :

Damned, going through all these cables is like going "through a fractal on a breaking wall"... (Seal in Crazy)

Sadly I couldn't identify any of the cables I was talking about :-( so I decided to use another method : deport a fuse and put a switch in series...

Next step : find the correct fuse...

Denis.

[groar]

First find the description of the engine compartment fuse box in the revue :

Here it's the #A

From the description on the left the more interesting one is the #4 as it's about the stop solenoid and not about the ECU.

I tried to remove each #4 fuse and tried to start to the engine hoping that the ECU will start but not the engine. Sadly for all of them the ECU and the engine started...

The description of #2 fuse is about solenoids and the ECU, so logically it was not the correct one, but I tried it anyway... I removed the #2 fuse. The ECU started when I turned the key to II but the engine didn't start when I turned the key to III At least I identified an anti-thief mechanism

The idea was then to deport the fuse. I tried to search on web sites for a "false" fuse permitting to connect cables on it, so to build a fuse deport and put a switch in series. In fact I quickly found that the electric connectors have the same size as the fuse :


so the solution was easy :


And you just have to connect a fuse holder and a switch :


Next step : doing tests...

Denis.

[groar]

As shown in the 1st post, it works : the engine stops while nor the ECU nor the accessories are reset : mov00011.mp4 (2.8MB).

So finally I installed the switch on the DashBoard :

Currently it's temporary. To use the switch I push it down with the forefinger and the middle finger then push the button with the thumb. The place is much more convenient than the key for 2 reasons. First it's much more closed to the horizon so the eyes doesn't have to move as much. Second my right hand can go very easily from the steering wheel to the switch, while it's more difficult to go to the key hidden under the steering wheel.

The last mystery... will I be able to use this switch to FAS ? The stop solenoid is coded, so the solenoid and the ECU must be able to dialog for the solenoid to accept to start, or the ECU to accept to start the solenoid (I don't know the detail). Concretely I may be able to switch the engine off with the switch, but may not be able to restart the engine by bump starting if the solenoid isn't restarted...

As said in the 1st post, it works well so while rolling in neutral when the switch is pushed to off then the engine stops, then when the switch is pushed back to on then the heat plugs are switched on and the airbag resets. After a while, a bump start restarts the engine as usually when I was using the key

From my tests this is what I can say about using the FAS kill switch against using the key :

Positive :

• The place I put the switch is more convenient than where is the key
• The steering wheel assistance doesn't disappear suddenly now, much better at home
• The accessories aren't stopped, noticeably the rear view camera used as the passenger mirror
• The ECU isn't stopped and reset so the odometer counts every meter, but over all I feel safer
• The switch can be used as an anti-thief mechanism

Negative :

• When I Fas to a stop, the key have to be back to I before being able to start the engine, but not a real annoyance.
• The switch used is a regular one, so I have to push one side to stop then the other side to stop. It's noisy, it will not disturb me but may disturb passengers. I may change it if I can find a simple push button.
• The electric windows aren't reset so the driver window stay in automatic mode and is much more difficult to move precisely.

Have fun,

Denis.

[Piwoslaw]

Damn, why don't I have as much determination as Groar?

THANK YOU VERY MUCH, DENIS!!!
I've been looking for a way to turn my engine off, I've asked around at my local Pug forum, I've also asked them if my engine has a solenoid and if so, where? And nothing. As we say here, they all have water in their mouth. My engine is so new it's hard to find info on it (everything is about the older 2.0HDi). So I gave up. But thanks to your step-by-step instruction I will keep trying.

[groar]

Originally Posted by Piwoslaw

Damn, why don't I have as much determination as Groar?

I want to have longer tanks than PaleMelanesian As he is always improving his hypermiling skills, I have to ecomod the megane more and more and...

THANK YOU VERY MUCH, DENIS!!!

Your thanks are my pleasure

I've been looking for a way to turn my engine off... But thanks to your step-by-step instruction I will keep trying.

I think the test by removing the fuses one after the other is a great way to test an engine without documentation, but I'm not an electrician and I don't know what are the risks to proceed to such a test
Personally I would hesitate to do it on a newer diesel with a high pressure pump (ie common rail) as they are certainly much more complicated and sensitive. Now I don't want to make you hesitate to test that on your HDi.

Have fun,

Denis.

[Arragonis]

I like the French auto manual. What is the French for the key phrase that strikes fear into anyone reading a Haynes manual for the first time - Reassembly is the reverse of disassembly...

[groar]

Arragonis, I can't find such a fear sentence on the ETa manual.

Sorry for the French pictures . I tried to be useful to people as dumb as I am in mechanic/electricity.
in French disassembly is "dépose" and reassembly is "repose".

The page 2 says something like that :

• this book is for reparation professionals and competent amateurs...
• the technical information in this documentation is for professionals only, some concern safety of the vehicle...
• some operations described in this revue need a specific clearance vis-à-vis the country legislation. The professional will ensure he owns the correct clearance vis-à-vis his country legislation...

I bought it only to have some specifications such as compatible oil... This is the first time I use it to modify my car myself. If the kill switch works well without any bad effect (I used it only on 40km/25mi by now) then the revue will quickly pay back.

Have fun,

Denis.