fuel cut off swithch
Moderator: martauto
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.
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.
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.
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.
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.
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.
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
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
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darren_rice
- E30 Zone Newbie
- Posts: 63
- Joined: Mon Dec 26, 2005 11:00 pm
- Location: Dublin
were bouts are ya?
Best way is getting a snap of steering wheel!
That and a big dog..lol!
Cheers
Dar
Best way is getting a snap of steering wheel!
That and a big dog..lol!
Cheers
Dar
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.
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.
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.
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.
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.
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.
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darren_rice
- E30 Zone Newbie
- Posts: 63
- Joined: Mon Dec 26, 2005 11:00 pm
- Location: Dublin
haha!
Was just down in limerick the other nite,
Looking at that yellow trueno with my cousin!
Ever see it?
Cheers
Dar
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Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
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).
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).
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.
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.
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Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
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.
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.
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Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
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.318is_irl wrote: @brian explain more about this ecu feed??