fuel leak inside car, driver's floormat wet (!!!)

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Rigmaster
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fuel leak inside car, driver's floormat wet (!!!)

Post by Rigmaster »

wife noticed a fuel smell in the driveway this morning, so we investigated and found that our 88 635csiA had fuel residue inside the car, driver's side- enough to wet the carpet. We only drive this car occasionally, and it's had a battery drain of some sort for a while, if left unattended for a few days, the battery is usually dead.

Also noticed today that the TPS (throttle Position sensor) seemed to be buzzing even after the key was turned off, and there's another buzzing sound coming from the trunk on the passenger side. I have not had a chance to look at it yet, but I'm assuming maybe a stuck relay causing the fuel pump to continue to run after the car is turned off (?).

Should be easy enough to diagnose, but what about the fuel inside the car?? Are there fuel lines inside the car? (I don't think so) But perhaps a fuel vapor/return line that's broken or somehow pushing fuel out??

I did a quick search, but didn't see anything definitive like this.


TIA!


Rig
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Brucey
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Post by Brucey »

there shouldn't be fuel inside the car.... but on some 6ers there were

1) evaporative recirculation systems and

2) fuel cooling systems

which add complexity and add potential for weird fuel leaks.

If the fuel leak is bad enough it'll look wet when the car is cold and the fuel pump is on (and I certainly wouldn't drive it in that condition). The fuel pipes run under the LHS of the car and into (and out of) the engine bay on the LH side.

The TPS cannot make a noise but the ICV nearby can and does when the ignition is on.
The fuel pump(s) also make a noise when they are running, and that is the only thing that is in that area (apart from the SLS pump I guess) which could make a noise.

Both make noise when the main relay is on (or bypassed) and similarly the fuel pump relay is triggered (or bypassed). If the fuel pump or SLS pump is running all the time this will flatten the battery in short order.

The car is probably unsafe to drive if the fuel pump is set to run all the time; it is meant to cut out in the event of any problem so that it cannot add about two litres of fuel per minute to any fire there might be in the event of an accident.

Any fuel leak inside the car is especially dangerous because you can easily end up with an explosive mixture of fuel vapour and air inside the cabin. One spark and ka-boom, you, the car, and parts of the nearby neighbourhood are history...

It sounds to me as if you have a fair bit of work to do....you can pull fuses one at time to see if there is current being drawn on particular circuits but be careful; sparks and fuel leaks don't mix!

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Post by Rigmaster »

Thanks Brucey.

I certainly have some work to do, and I definitely will not be starting or driving the car until the fuel leak is cleaned up and the source identified and repaired.

I am 99.9% sure it's the TPS that's buzzing, my first thought was the ICV, but I know which is which and the sound was not coming from the ICV. The battery was too flat to crank the car, so that may be a factor in the noise as well.

I'll check on it a bit more later today (hopefully) and report back.


Thanks!

Rig
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Post by Pod »

The fuel lines run under the car, then up the outside of the left-hand footwell. I'm wondering if there is a leak in that area and it is running in through either an "intentional" hole or maybe a rusty hole?

Whatever, even if the pump is running on after the engine is switched off, there must be a leak in one of the pipes or rubber lines! Maybe its spraying petrol onto the firewall. I'd be very careful when looking for it and wouldn't be smoking a fag whilst you're at it :wink: In fact, keep a fire extinguisher handy.
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Post by Rigmaster »

Thanks for the reply Pod.


The crazy thing is, the car has some generic rubber all-weather floor mats, and there was a decent amount of fuel residue on top of the rubber mat.

#-o
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Post by Pod »

Rigmaster wrote:Thanks for the reply Pod.


The crazy thing is, the car has some generic rubber all-weather floor mats, and there was a decent amount of fuel residue on top of the rubber mat.

#-o
That's worrying. If there was fuel on top, then likely there was more underneath. The carpets can soak up a great deal of water when there is a leak. That means that you may well have an amount of fuel sitting under them. Looks to me that you need to remove all of the carpets and see what's underneath before you do anything else. Be careful, and let us know how you get on?
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Post by Pod »

Pod wrote:
Rigmaster wrote:Thanks for the reply Pod.


The crazy thing is, the car has some generic rubber all-weather floor mats, and there was a decent amount of fuel residue on top of the rubber mat.

#-o
That's worrying. If there was fuel on top, then likely there was more underneath. The carpets can soak up a great deal of water when there is a leak. That means that you may well have an amount of fuel sitting under them. Looks to me that you need to remove all of the carpets and see what's underneath before you do anything else. Be careful, and let us know how you get on?

Did you resolve this problem?
Chris Wright

Post by Chris Wright »

Be aware that some of the later cars had a fuel cooling option that Brucey mentioned. The fuel line runs under the drivers floorboard and up the firewall to the back of the fuel rail, then out of the fuel pressure regulator at the front of the fuel rail it runs to the firewall and into the scuttle where the wiper motor and heater blower are. It runs across the scuttle to the passengers side and back out and runs forward to a chamber built into the A/C hose to cool the fuel. It then runs back to the scuttle, back across to the drivers side and back out and down the firewall to return to the fuel tank.

So you can see there is lots of opportunity to leak fuel into the scuttle which could find its way inside.
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Post by slofut »

Chris Wright wrote:Be aware that some of the later cars had a fuel cooling option that Brucey mentioned. The fuel line runs under the drivers floorboard and up the firewall to the back of the fuel rail, then out of the fuel pressure regulator at the front of the fuel rail it runs to the firewall and into the scuttle where the wiper motor and heater blower are. It runs across the scuttle to the passengers side and back out and runs forward to a chamber built into the A/C hose to cool the fuel. It then runs back to the scuttle, back across to the drivers side and back out and down the firewall to return to the fuel tank.

So you can see there is lots of opportunity to leak fuel into the scuttle which could find its way inside.
Damn that sounds like British engineering, did they conspire with Jaguar to come up with this? ...flame suit on #-o
'87 635csi, 5sp man, dk blu on pearl beige
'88 635csi, auto, black on grey
'63 BMW Isetta
'75 XJ6C, 2dr, warm 350
'86 XJ6, th700r4
'75TR6
'64 Olds 88 conv
"68 T120 Bonneville
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Post by Pod »

slofut wrote:
Chris Wright wrote:Be aware that some of the later cars had a fuel cooling option that Brucey mentioned. The fuel line runs under the drivers floorboard and up the firewall to the back of the fuel rail, then out of the fuel pressure regulator at the front of the fuel rail it runs to the firewall and into the scuttle where the wiper motor and heater blower are. It runs across the scuttle to the passengers side and back out and runs forward to a chamber built into the A/C hose to cool the fuel. It then runs back to the scuttle, back across to the drivers side and back out and down the firewall to return to the fuel tank.

So you can see there is lots of opportunity to leak fuel into the scuttle which could find its way inside.
Damn that sounds like British engineering, did they conspire with Jaguar to come up with this? ...flame suit on #-o
Yep. You Yanks could never accept the fact that we built a successful supersonic airliner when you couldn't :lol:
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Post by BlackBetty »

Pod wrote:
slofut wrote:
Chris Wright wrote:Be aware that some of the later cars had a fuel cooling option that Brucey mentioned. The fuel line runs under the drivers floorboard and up the firewall to the back of the fuel rail, then out of the fuel pressure regulator at the front of the fuel rail it runs to the firewall and into the scuttle where the wiper motor and heater blower are. It runs across the scuttle to the passengers side and back out and runs forward to a chamber built into the A/C hose to cool the fuel. It then runs back to the scuttle, back across to the drivers side and back out and down the firewall to return to the fuel tank.

So you can see there is lots of opportunity to leak fuel into the scuttle which could find its way inside.
Damn that sounds like British engineering, did they conspire with Jaguar to come up with this? ...flame suit on #-o
Yep. You Yanks could never accept the fact that we built a successful supersonic airliner when you couldn't :lol:
Successful is kinda a broad definition when it comes to the Concorde :D
And Hey, are you saying the French did not contribute anything? :D
Plus we were busy getting ready to go to the moon :D
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slofut
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Post by slofut »

Pod wrote:
slofut wrote:
Chris Wright wrote:Be aware that some of the later cars had a fuel cooling option that Brucey mentioned. The fuel line runs under the drivers floorboard and up the firewall to the back of the fuel rail, then out of the fuel pressure regulator at the front of the fuel rail it runs to the firewall and into the scuttle where the wiper motor and heater blower are. It runs across the scuttle to the passengers side and back out and runs forward to a chamber built into the A/C hose to cool the fuel. It then runs back to the scuttle, back across to the drivers side and back out and down the firewall to return to the fuel tank.

So you can see there is lots of opportunity to leak fuel into the scuttle which could find its way inside.
Damn that sounds like British engineering, did they conspire with Jaguar to come up with this? ...flame suit on #-o
Yep. You Yanks could never accept the fact that we built a successful supersonic airliner when you couldn't :lol:
That was a badass plane!
'87 635csi, 5sp man, dk blu on pearl beige
'88 635csi, auto, black on grey
'63 BMW Isetta
'75 XJ6C, 2dr, warm 350
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'75TR6
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Post by WelshBentleyBoy »

Why do the English drink warm beer?

Probably because they let Lucas make their refrigerators!

I can get away with this as I am a Welshman! :D
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Post by BillDe »

WelshBentleyBoy wrote:Why do the English drink warm beer?

Probably because they let Lucas make their refrigerators!

I can get away with this as I am a Welshman! :D
:lol:
Rigmaster
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Post by Rigmaster »

Update:

apparently the fuel pump got stuck on (bad relay?) last time the wife drove the car, the pump ran until the battery died.

Result? Engine crankcase was FULL of a fuel/oil mix, I mean FULL. I didn't measure the exact amount I drained out, but probably close to 5 GALLONS of fuel/oil. The fuel inside the car apparently came from a broken vacuum line under the driver's side of the dash. There really wasn't more than a teaspoon or two of fuel inside the car, but the smell was strong.


I drained the crankcase and let it "air" out for a week, then replaced filter and refilled with fresh oil. Also had to refill the fuel tank and charge the battery. It took a small shot of starting fluid to get things to catch, but it now starts and runs fine.

I still have not figured out what caused the fuel pump to keep running, but as mentioned, I'm leaning towards a bad relay. For now the car is sitting with the battery ground cable disconnected until I can troubleshoot some more. I guess I should try to figure out which injectors are sticking open as well, if they were closing off completely like they should, I don't think the crankcase could have filled with fuel - or am I missing something (??).


One for the books, that's for sure.
euro24

Post by euro24 »

Pod wrote:
slofut wrote:
Chris Wright wrote:Be aware that some of the later cars had a fuel cooling option that Brucey mentioned. The fuel line runs under the drivers floorboard and up the firewall to the back of the fuel rail, then out of the fuel pressure regulator at the front of the fuel rail it runs to the firewall and into the scuttle where the wiper motor and heater blower are. It runs across the scuttle to the passengers side and back out and runs forward to a chamber built into the A/C hose to cool the fuel. It then runs back to the scuttle, back across to the drivers side and back out and down the firewall to return to the fuel tank.

So you can see there is lots of opportunity to leak fuel into the scuttle which could find its way inside.
Damn that sounds like British engineering, did they conspire with Jaguar to come up with this? ...flame suit on #-o
Yep. You Yanks could never accept the fact that we built a successful supersonic airliner when you couldn't :lol:
It's not that we couldn't, it's that we realized early on it was silly and impractical. Kind of like colonizing India or something :wink:
euro24

Post by euro24 »

Rigmaster wrote:Update:

apparently the fuel pump got stuck on (bad relay?) last time the wife drove the car, the pump ran until the battery died.

Result? Engine crankcase was FULL of a fuel/oil mix, I mean FULL. I didn't measure the exact amount I drained out, but probably close to 5 GALLONS of fuel/oil. The fuel inside the car apparently came from a broken vacuum line under the driver's side of the dash. There really wasn't more than a teaspoon or two of fuel inside the car, but the smell was strong.


I drained the crankcase and let it "air" out for a week, then replaced filter and refilled with fresh oil. Also had to refill the fuel tank and charge the battery. It took a small shot of starting fluid to get things to catch, but it now starts and runs fine.

I still have not figured out what caused the fuel pump to keep running, but as mentioned, I'm leaning towards a bad relay. For now the car is sitting with the battery ground cable disconnected until I can troubleshoot some more. I guess I should try to figure out which injectors are sticking open as well, if they were closing off completely like they should, I don't think the crankcase could have filled with fuel - or am I missing something (??).


One for the books, that's for sure.
Yikes!!!
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Post by Pod »

Interesting. Surely the fuel return line should have taken the petrol back to the tank if everything was working properly. So I think you need to check the pressure regulator and return line first off. I imagine that with the pump running, the fuel had to have somewhere to go, so I guess it must have got past the injectors or maybe cold start valve?

Anyway, I'm glad you got it diagnosed and the whole lot didn't go up like a bomb - I reckon you missed a potentially catastrophic accident there!

Do let us know how you get on?
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Post by Pod »

euro24 wrote:
Pod wrote:
slofut wrote: Damn that sounds like British engineering, did they conspire with Jaguar to come up with this? ...flame suit on #-o
Yep. You Yanks could never accept the fact that we built a successful supersonic airliner when you couldn't :lol:
It's not that we couldn't, it's that we realized early on it was silly and impractical. Kind of like colonizing India or something :wink:
Or North America :lol:
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Post by slofut »

Rigmaster wrote:Update:

apparently the fuel pump got stuck on (bad relay?) last time the wife drove the car, the pump ran until the battery died.

Result? Engine crankcase was FULL of a fuel/oil mix, I mean FULL. I didn't measure the exact amount I drained out, but probably close to 5 GALLONS of fuel/oil. The fuel inside the car apparently came from a broken vacuum line under the driver's side of the dash. There really wasn't more than a teaspoon or two of fuel inside the car, but the smell was strong.


I drained the crankcase and let it "air" out for a week, then replaced filter and refilled with fresh oil. Also had to refill the fuel tank and charge the battery. It took a small shot of starting fluid to get things to catch, but it now starts and runs fine.

I still have not figured out what caused the fuel pump to keep running, but as mentioned, I'm leaning towards a bad relay. For now the car is sitting with the battery ground cable disconnected until I can troubleshoot some more. I guess I should try to figure out which injectors are sticking open as well, if they were closing off completely like they should, I don't think the crankcase could have filled with fuel - or am I missing something (??).
One for the books, that's for sure.
WOW! I've never heard of that one in a later, injected automobile!
It's not uncommon on old britbikes to have the sump full of fuel if you forget to shut the fuel petcock off after riding. The petcocks were also prone to leaking and would do the same sometimes even if you turned it off. Of course that's gravity feed and easily explainable.
Similar with older cars when people add an electric fuel pump along with the old mechanical, diaphragm ruptures in the mechanical pump and the fuel from the electric pump runs through the diaphragm right into the engine block. ...Kaboom! :shock:

I hope you pinpoint the cause of this (didn't you say there was some altered wiring at the fuel pump relay) I would really like to have a heads up on this kind of situation.
'87 635csi, 5sp man, dk blu on pearl beige
'88 635csi, auto, black on grey
'63 BMW Isetta
'75 XJ6C, 2dr, warm 350
'86 XJ6, th700r4
'75TR6
'64 Olds 88 conv
"68 T120 Bonneville
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Brucey
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Post by Brucey »

the fuel pump should, for safety reasons, only run during

a) cranking and/or
b) engine running

If it runs continuously then it is going to empty the tank or cause a fire or something.

Even so the fuel system must have a mighty leak in it in order to empty the tank before the battery went flat.

I suspect that one of the injectors was jammed open or was leaking (or possibly the FPR has failed to leak into the inlet via the compensation hose....), then the inlet manifold filled up. From there the fuel can only drain out via the air temperature hose (thus getting into the cabin) or via the inlet tract, through an open inlet valve, past slightly worn piston rings, into the sump.

Crikey though.... that is an unbelievably dangerous state of affairs....

hope you get it sorted out OK.

cheers
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slofut
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Post by slofut »

Rig,
Any update on your fuel problem?
'87 635csi, 5sp man, dk blu on pearl beige
'88 635csi, auto, black on grey
'63 BMW Isetta
'75 XJ6C, 2dr, warm 350
'86 XJ6, th700r4
'75TR6
'64 Olds 88 conv
"68 T120 Bonneville
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Post by sansouci »

bump
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