Heaven forbid you have an accident in your 5 worse case scenario the cars smashed up badly, fuel line broken and ignition on, will the fuel pump continue to pump fuel out all over the place and then become a very serious fire hazard,
Does the 5 have a impact fuel cut off sensor that will activate and cut the fuel pump off on impact if so were is it could any one advise and is it possible to have one fitted is so were would be the best position to fit.
Hi Alan,
I would suspect the crash sensors would do this, but I don’t know for sure - you need a reliable answer from Robbie - - - - Sorry.
Alan - me again. No answer from Robbie yet, but having checked the wiring manual your suspicions appear to be correct.
The ignition switch turns on the main relay (under the bonnet) which in turn switches on the pump relay (in the dash fuse panel) this supplies the fuel pump direct. The main relay also controls the igntion coils (top of the engine) and the fuel injectors.
You have two choices as I see it - the simple route, either make or get a yellow label with “Igntion and fuel pump switch” (black letters) and stick it on top of the steering wheel top cowl above the ignition switch, or - go the full track route and fit an ignition switch and a fuel pump switch in a “highly visible location” and get them clearly marked up. The latter will prove more difficult, unless you start ripping the dash apart to turn the car into a trackday version.
My suggestion? Go to the nearest Electrical wholesaler, who sells ‘Control gear’ and ask them for a 22.5mm Emergency Stop Push (locking type) and fit this on the rear shelf front (between the seats) connecting it into the pump live wire. (an emergency stop push has normally closed contacts) The pump live should be a red/blue You will need to drill a 22.5mm hole in the parcel shelf to do this - remove the carpet and take the shelf right off, you will see what space is available between the front of the shelf and the petrol tank to do this. Obviously you will also have to cut a similar hole in the carpet (ouch). With the stop push, you should be able to buy either a 60mm round BLANK yellow label, or an oblong one - take this to an engraver, and ask them to engrave “FUEL CUT OFF SWITCH” - which goes between the ‘head’ (outer push) and the panel hole - outside the carpet of course!
Only one thing wrong with this - it may not be highly visible to an outsider, so you could think about mounting the push somewhere more visible, but the label size may be awkward, you may have to compromise on that. Also - if mounting on or near the dash, then you could connect into the pump relay (live) circuit, or the pump live going from the relay. Dash wiring is very difficult to access, especially around the dash fuse panel. If you opt for this version, PM me your email address and I’ll send you a wiring diagram which should help. Better still - connect the push into the main relay coil live feed from the ignition switch, and you have covered all the electrics that matter. You could use a standard toggle switch, but it will be harder for anyone to locate, and more easily switched off while driving, so I would advise against that.
Someone may advise you to fit a battery switch, but as these normally mount on top of the battery, you would need a label outside the boot to identify where the main battery switch is, which could mean a crowbar to the boot in an emergency. If the cars already a write off, then you may not care, but you would be hoping you can either pull the boot release, or they just happen to have a crowbar in their coat pocket - - - - -
NOTE: the usual ‘rider’ covers, this assumes you know what you are doing, and if anything goes wrong - don’t blame me!
The fuel pump will stop running in an accident, can’t remember how off the top of my head.
Hi Robbie - Nothing wrong with your head, but would appreciate some assurance of that (above) - I’m worried myself now! I can’t see any link between the ignition switch, main relay, fuel pump relay or pump that’s connected to, or via the EMS, so what would switch any of the circuit off in an accident? I thought it might be the crash sensors (maybe as part of the air bag switches) but doesn’t seem to be any link between the above and the fuel pump circuit.
Or just turn the key off? I’ve done this with two broken fingers, I certainly couldn’t have turned round to hit a button between the seats at the time. Seems a lot of time effort and grief to make something that no one will ever use.
It’s all electronic, if the PCM stops seeing an engine run signal (ie engine has stopped) it turns the fuel pump off. Earlier cars had a circuit opening relay for this purpose and had a feedback from the coils as the run signal. It’s not a simple as a hard wired link between 2 components.
I doubt a car could be mass produced with a fuel pump that would continue to run in the event of an accident that caused a fuel leak.
Captain Muppet, yes, true, but the assumption in the first post was the driver was unconcious.
granted, if there was a passenger, and they knew what to do, and could reach over then they could switch off the ignition, but that’s a big ‘if’.
I did list several solutions, so the first wasn’t the only one, but that was the easiest IMHO - other than sticking a label on the steering cowl, which is I understand, good enough for Sprints, using a standard car.
Thanks Robbie, you beat me to it by a whole day!
However, just to complicate matters, how long can the engine run if the car’s upside down? Assuming it just flipped, and the engine didn’t stall.
(OH - and the drivers unconcious - - - -!)
The problem with unwritten assumptions is that no one else knows what they are.
Either stick to the standard key-off OR go for a MSA/FIA spec isolator which kills the engine and fuel pump (these have a big red key both inside and outside the car). If there is an international safety standard it makes sense to stick to it.
Hi Gerryn Thanks for the details I would like to think there is a cut of of some description in the cars wiring loomyou would like to think so in a modern 6yr old car, but on my older cars ie Austin Montego, there was a cut off switch and a rest set button which was hidden under the dash and sfter a front end imapct this switch had to be reset, I would like to go for a smaller type of switch, I have seen switches with a cut off emblem on the switch, but also has a lift up movement to it thay may fit into the dash I have blank for the air con on my sport that with a little modification would possible do, some think to hunt down and do over the winter months whilst the car is stood up, me thinks
Thanks every one for your imput very interesting.