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FUEL SMELL BUT NO LEAK!


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Happy upcoming New Year to everyone. I'm losing the will to live over my failure to locate the cause of an obvious fuel smell at the rear, especially in the boot. The car has a Facet fuel pump mounted in the spare wheel well. All the hose joints and inline strainer etc are completely dry. At the start of 2020 I replaced all hose with R9. This included the filler neck hose and filler cap. Any thoughts? Shots of Heldtite sealing in filler neck and filler cap.

Willie

10. Heldite seals joint ready for  petrol cap neck.JPG

14b..JPG

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FWIW that looks like a repro cap, Its trying to seal on a fibre washer similar to the originals, you could try swapping that for a Viton "O" ring which would provide a better seal. Do you by any chance have an original TR4 tank with a breather pipe out on the right hand side that goes down and into the rear wheel arch ? If so as you now have a vented cap you could happily block that pipe off.

Stuart.

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Tank is Moss aluminium circa 2006.  Just before raising the subject here, I painted Heldtite on the half of the sender unit I could access straightforwardly. Perhaps do the same to the front from the cockpit! The fuel cap also from Moss supplied as photo.

I didn't mention it, but the smell builds even when the car has been stationary.

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8 minutes ago, Willie said:

Tank is Moss aluminium circa 2006.  Just before raising the subject here, I painted Heldtite on the half of the sender unit I could access straightforwardly. Perhaps do the same to the front from the cockpit! The fuel cap also from Moss supplied as photo.

I didn't mention it, but the smell builds even when the car has been stationary.

Yes but did you fit the tank breather from your original?

Stuart.

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I think Stuart may have spotted a problem with the fuel filler cap. The centre metal part in the lid should seal on the red gasket but looks a fraction too small in diameter from the photo. I recently got a locking cap from Moss (yet to be fitted) with a better seal. I have an original cap and it has the top seal part approx 61mm diameter. Try some engineers blue or even a bit of grease on the edge of the top sealing part and see where it touches in relation to the red gasket. Just need to check my locking cap now to see if it is vented!

Check the rubber fuel connector on the fuel line under the car located on the inside of the nearside chassis member near the diff area. There is another near the front as well. Either replace with R9 hose  or do as I have and replace the full length of metal pipe from the tank to the engine bay in one length so 2 less connections to worry about. Never understood why these connectors were used unless it was done for easier assembly on the production line.

I have a friend with a TR250 who has an aluminium tank. If the mounting points are not flexible enough or have been over tightened, the tank can crack near the mounting points as the body flexes in his experience.

Keith

Edited by keith1948
extra info.
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44 minutes ago, stuart said:

Do you by any chance have an original TR4 tank with a breather pipe out on the right hand side that goes down and into the rear wheel arch ?

+1

I have a Spitfire tank in my 3A that had a pipe like that. I left it open when I fitted it.

Like you I found that the smell in the garage occoured simply with the car sitting there not doing anything. I had a vented filler cap so I simply blocked off the end of the breather pipe. End of smell.

(But only after I had gone to the hassle and expense of rigging up a ducted extraction fan on the instructions from my wife.)

 

Willie,

Just realised that you live in Hereford.

Don't bother doing anything to stop the smell. The pong that comes out of the chicken factory masks anything else.

Charlie.

Edited by Charlie D
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10 minutes ago, keith1948 said:

 

Check the rubber fuel connector on the fuel line under the car located on the inside of the nearside chassis member near the diff area. There is another near the front as well. Either replace with R9 hose  or do as I have and replace the full length of metal pipe from the tank to the engine bay in one length so 2 less connections to worry about. Never understood why these connectors were used unless it was done for easier assembly on the production line.

The two short sections of rubber pipe under the car at the front and the rear was to be able to assemble easily the line as it wouldn't pass through in one piece.

Stuart.

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Just to reiterate, the smell is inside the boot, but all connections are dry - checked numerous times.ALL hoses renewed with R9 early in 2020. There are two hexagonal blanking plugs on top of the tank, also dry.  Is one of these for the breather? Photo of the subject will be appreciated, together with any part number and where to get one.  I have owned the car since early 2013, so wasn't involved in the tank swap.

For the record, Charlie, I live upwind of the chicko!! PM me if you want to take a look!

Willie

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Has anyone tried fuel leak detection kits such as this one that uses UV dye?

https://www.amazon.co.uk/Torch-Detection-Fluid-Petrol-Diesel/dp/B00TU9BHN6/ref=asc_df_B00TU9BHN6/?tag=googshopuk-21&linkCode=df0&hvadid=218093857332&hvpos=&hvnetw=g&hvrand=142262203243439808&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006705&hvtargid=pla-717998471679&psc=1

Not sure it would work if vapour coming from filler cap or vent pipe though.

Keith

p.s. Stuart I can see why fuel pipe would be in 3 sections to speed up assembly but with patience a single length can be fitted.

p.p.s. Willie I remember doing some work inside the chicken factory in Hereford on more than one occasion. Smells better inside than out I seem to remember!

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3 hours ago, Willie said:

Just to reiterate, the smell is inside the boot, but all connections are dry - checked numerous times.ALL hoses renewed with R9 early in 2020. There are two hexagonal blanking plugs on top of the tank, also dry.  Is one of these for the breather? Photo of the subject will be appreciated, together with any part number and where to get one.  I have owned the car since early 2013, so wasn't involved in the tank swap.

For the record, Charlie, I live upwind of the chicko!! PM me if you want to take a look!

Willie

HI Willie

Sorry, late in on this. You say you have changed all the hoses for R9, as did I, however, did you change the 'downpipe' the fat hose connecting the filler cap to the tank ?  Due to size and location they tend not to be fuel/ E5 /E10 quality or changed often, could have been re-used during the tank swap ? I found mine had rotted from the inside out. Looked fine, but wasn't and the cause of the fuel smell in the boot. Worth a look 

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Willie - if Mike's suggestion of checking the cap to tank hose turns out not to be the culprit, then that doesn't leave many other options other than the tank.

You mentioned it had been replaced with an alloy tank in approx 2006  - the quality of alloy tanks I've seen from that sort of era have been quite hit and miss, with alloy welding looking like lumpy porridge and general poor quality tarnishing all manufacturers with the same brush. A very minor weep from a pinhole in a weld bead may not be very easy to spot but could be the culprit.

Is the tank well exposed with the boot board  and cockpit board removed - if so, how about dusting it all over with talcum powder and that should show up any leaks. If the tank is the problem, and you need another one, give me a call as I can help.

You also mention you have a Facet fuel pump in the boot - could the pump itself rather than it's hoses be the culprit? Was there a reason why you abandoned the original AC Delco pump fitted to the engine? You could temporarily remove the Facet and seal its inlet and outlet feeds to see if that removes the source of the smell on the basis of trying to eliminate as many options as you can.

Good luck and keep us posted!

Cheers Rich

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Rich,

         I inherited the car with the Facet fuel pump. I suspect stealing a couple of BHP's here and there was the motive [electric fan also and 123 Dizzy]. I've done a fair bit of running fingers over seams and mounting lugs but no smell of fuel so far.  The smell is obvious even after 24 hours, but no damp or stained areas! Hence losing the will.

I'll redouble efforts in this nice mild weather and see what comes!!

Best wishes     Willie

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Worst case situation: I just replaced my aluminium tank, same provider iirc, suspecting a micro crack in a weld.  There was no visible evidence of a leak but it doesn't take much to create a stink. The replacement steel tank is smell free.

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Hi there,
Unfortunately I had the pleasure several times that the aluminum tanks were not tight at the weld seams! An exhaust gas tester with an HC display was a great help in the determination. The HC value goes up steeply at the leak. The fuel immediately gasifies, so you can only smell it. That's why I now have every new aluminum tank tested for leaks and, if necessary, re-welded. that makes me a specialist company. Testing of new parts has unfortunately become normal.

Many greetings
Ralf

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Thank you everyone for the useful suggestions.  I'll try to seal the sender first, then look t filler hose. Keep going until no smell, then......argh, more expense!! I'll feedback on the outcome [eventually].

Best wishes to all.                 Willie

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I recently got some ethanol proof (resistant) filler hose from this supplier.

https://www.holden.co.uk/p/fuel_filler_hose_lined_2_in_51mm_dia_x_200mm_long

Not sure whether it is R6 or R9 spec though but permeability probably not an issue here because fuel cap is vented. Check that the hose clamps on this hose are tight enough.

Re earlier comment on cork gasket on fuel sender - this is worth checking out. I have just got a Viton rubber seal (E10 proof) from Moss to replace this. I seem to remember that I used some sealant on the threads of the screws that hold the sender in place because I had a fuel smell in the boot for a while. Never did really get to the reason but it went away after doing various jobs. Is the connection under the tank ok?

Keith

 

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16 minutes ago, Lebro said:

Good point about the screws, I have tiny fiber washers under the heads of mine to seal.

Bob.

Which is correct and OE specified.

Stuart.

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1 hour ago, Willie said:

Thank you everyone for the useful suggestions.  I'll try to seal the sender first, then look t filler hose. Keep going until no smell, then......argh, more expense!! I'll feedback on the outcome [eventually].

Best wishes to all.                 Willie

Talc is the best way to find what is quite possibly a miniscule leak somewhere, dust it everywhere even along the hoses and round the tanks seams and the body of the pump, then check the fuel hose all the way along underneath as well and all the way up to and including the carbs as it could be from anywhere as the smell pervades for a long way.

Stuart.

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16 hours ago, keith1948 said:

p.s. Stuart I can see why fuel pipe would be in 3 sections to speed up assembly but with patience a single length can be fitted.

 

Not in original OE Steel in its factory position it cant.

Stuart.

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