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fuel cut off swithch
Posted: Thu Feb 09, 2006 10:09 am
by 318is_irl
is there one of these is the e30 and if not whats the best way of wireing one in

Posted: Thu Feb 09, 2006 10:19 am
by dsio
I doubt this is the best way, but I had a severe flooding problem that made my M10 hard to start, so I wired an unloader switch into the fuel pump relay connector that works very well for me.
It was easy to do, though a bit wastefull in that it discharges everything in the fuel rail before it actually runs out. Don't know how to turn the injectors off since I think they come a bit too close to the ECU's territory.
Posted: Thu Feb 09, 2006 11:23 am
by 318is_irl
a bit more info on this please....where is the fuel pump relay?
Posted: Thu Feb 09, 2006 11:34 am
by dsio
On the M10 engined cars, you go to the side of the engine bay that has the fuse box, and look directly forwards to the front of the car from there.
Next to the AFM there is a black lid with kind of an "L" shape to it. You pull the lid off that box, and there you see two relays. There is a small silver one, and a large black one.
The large black relay is the fuel pump relay. If you pull it out, the fuel pump will not be powered, and when you try to start the car, whatever fuel pressure is left in the injector rail is used until there is no longer pressure, which isn't too long.
Then it doesn't become dry, but has no pressure, so nothing really comes out.
My car was flooded because the cold start injector was stuck open, flooding both the AFM and the engine with fuel. To solve the problem, I pulled the fuel pump relay and cranked it.
Without the relay it will try to start, and fire, but as soon as you stop the starter it will die. Then once theres no fuel left, it will not fire at all, and just turn over.
Then I put the fuel pump relay back in, turned the ignition on to engage the pump, and as soon as I turned the key it started beautifully.
Is this the kind of problem you have? Or is there some other reason you want to kill the fuel.
Posted: Thu Feb 09, 2006 11:40 am
by 318is_irl
nope i dont have a problem i want too cut the fuel as a saftey measure fair few cars robbed round my way lately.... i have a switch in my last e30 was fair handy....anyone know where the fuel relay is on a m42 engine
Posted: Thu Feb 09, 2006 11:48 am
by dsio
Ah now I get you. I use my unloader for that reason when its being left for an extended period.
You can't take it anywhere without the fuel pump so its a perfect method. For simplicity, pull out the relay.
Ill see if I can find a picture.
Posted: Thu Feb 09, 2006 12:06 pm
by 318is_irl
mould be much appreciated? how did you wire in the switch too the relay?
Posted: Thu Feb 09, 2006 12:19 pm
by dsio
I considered reading through the wiring diagram to find the ones I needed to kill, but I figured that when its not connected, it has the effect I wanted, so I used a multi-gated trigger switch, and cut all 7 or 8 wires going to the fuel pump relay holder, and wired the switch in series.
The control wire runs around the back of the firewall, and through to the cabin near the battery holder, behind the dash and into a switch in the glove box.
When I flip it in the ON position, the multi gate switch disconnects the entire fuel pump relay from its wiring. When I switch it off, it shorts all of the wires to their relay holder sockets.
It isn't the most elegant way to do it, but was the fastest since I could just crimp everything and lightly solder the thing in place.
My electrical engineering lecturer would be disgusted, but its not his car so bleh

Posted: Thu Feb 09, 2006 12:28 pm
by 318is_irl
ah.... i think ill just pull the replay lol
Posted: Thu Feb 09, 2006 12:30 pm
by dsio
Yea, its fairly easy to do lol.
Posted: Thu Feb 09, 2006 12:31 pm
by darren_rice
were bouts are ya?
Best way is getting a snap of steering wheel!
That and a big dog..lol!
Cheers
Dar
Posted: Thu Feb 09, 2006 12:36 pm
by 318is_irl
ha ha darren...the drifter from bmw-driver.net...
i have a snap off wheel but soo prefer my m tec wheel
Posted: Thu Feb 09, 2006 2:59 pm
by 318is_irl
come on someone must know where this replay is
Posted: Thu Feb 09, 2006 3:17 pm
by dsio
You sure you don't have that forward L shaped box near the AFM, and towards the headlights of the fusebox?
Posted: Thu Feb 09, 2006 3:49 pm
by 318is_irl
ill have a look after work lad thought that was only on the m10?
Posted: Thu Feb 09, 2006 4:00 pm
by dsio
Its on all E30s I think. I just checked and its on Bootyman's M20 as well as my M10 so I assume its standard. His is chrome and shiny though, not black ;)
Can you see on that picture, to the left of the shock tower brace, and just below where the air intake (specifically the AFM) you can see a chrome box, in a kind of L shape.
It is just overlapping the bottom of the AFM in that picture.
Posted: Thu Feb 09, 2006 4:15 pm
by 318is_irl
yip thats the one.... is there more than one relay in it and if so which one do i pull

Posted: Thu Feb 09, 2006 4:19 pm
by dsio
There are more than one.
Mine has two relays in it. One is a very tall relay, which is black. That is the fuel pump relay.
The other relay is silver and very short. NFI what that is to be honest, but its not the fuel pump. You may have more, you may have less. But with any luck it will just be those two.
Posted: Thu Feb 09, 2006 4:29 pm
by 318is_irl
lovely lol ill have a look after work and update tommorow......
so any other ways of securing your e30 then? there is an alarm fitted but its not working going having a look at it the weekend
Posted: Thu Feb 09, 2006 4:48 pm
by dsio
Well, the steering lock works. Its simple, but still a rather effective method of keeping theives at bay (I mean the factory steering lock thing, where with no key in it, you turn the wheel and it locks up).
One of my mates has a Mercedes 190E manual, and his method is pretty simple. He has a steel plate with a pin behind it that is on a hinge to the left of the clutch pedal.
You let the clutch out, reach under the clutch pedal, and flip the thing over, pull the pin out, turn it to the left, and it locks in place, right behind the clutch pedal.
If you step on the clutch, the pedal just can't move.
You can't move the thing back out of the way unless you really know how it works.
As you could imagine, its rather hard to steal a Mercedes 190E when you don't have a clutch pedal, but in the neighbourhood he lives in (cabulture) a European car with nice paint sticks out like a sore thumb, and is begging to be flogged.
Its a bargain basement / public housing area, much like the "council estates" as I believe you call them in England.
Posted: Thu Feb 09, 2006 4:56 pm
by 318is_irl
im living in lreland lad in a we town called limerick
Posted: Thu Feb 09, 2006 5:23 pm
by 316eyes
318is_irl wrote:im living in lreland lad in a we town called limerick
What do you call it now?
Posted: Thu Feb 09, 2006 5:28 pm
by 318is_irl
what do you mean
its still called Limerick
Posted: Thu Feb 09, 2006 11:36 pm
by darren_rice
haha!
Was just down in limerick the other nite,
Looking at that yellow trueno with my cousin!
Ever see it?
Cheers
Dar
Posted: Thu Feb 09, 2006 11:59 pm
by Brianmoooore
If I was going to nick an E30, I would overide a disconnected fuel pump relay in seconds, once I'd realised that the fuel pump was off.
What would slow me down would be a disconnected fuel pump feed, which is then short circuited between the fuse (11) and the pump.
Any attemt to jump this would just result in a blown fuse.
Best immobiliser is to disconnect the ignition feed to ECU and coil, (connector above glovebox), and to short out the green/purple to the pump (passes through glovebox).
Posted: Fri Feb 10, 2006 12:10 am
by dsio
I'm thankfull you're not a car thief Brian ;)
The upside is that the vast, vast majority of tea leaves have never been in, let alone owned a BMW, and would find it far too complicated compared to their Vauxhall
I spose taking the coil to distributor HT lead would be a fairly sure fire solution. I doubt they carry spare HT leads in the theive's handbag.
Posted: Fri Feb 10, 2006 8:35 am
by 318is_irl
@ dar which one we have two one with black bonnet one without.....
@brian explain more about this ecu feed??
Posted: Sun Feb 12, 2006 2:17 pm
by 318is_irl
right lads...... i dont have ths l shaped box with the relay?
Posted: Sun Feb 12, 2006 8:08 pm
by Brianmoooore
Just been looking back through this thread and trying to make sense of it.
The L shaped box (in Bootyman's pic ) is fitted to 6 pots, and contains the main DME and the fuel pump relay. There is also a usually empty relay socket (in the UK) for the heater of a lambda sensor as well.
On 4 pots the relays are under the wiring cover on the bulkhead.
Posted: Sun Feb 12, 2006 8:59 pm
by Brianmoooore
318is_irl wrote:
@brian explain more about this ecu feed??
Above the glovebox there is a white 2 pin socket with two green wires going to it, coming from the wiring loom there. This socket is the factort immobiliser connector. It will have a plug going into it leading to the alarm if the car has a properly fitted one, or an OBC, or will be fitted with a plug with a short loop of green wire connected to it if no alarm or OBC is fitted.