Fuel smell

So I've sealed the petrol tank lid with sealant and tape and I've still got a petrol smell in the cabin, especially after filling it with petrol, although it's there on and off all the time. I've never noticed the purge valve working, if this is malfunctioning would this cause a petrol smell?

So that I can eliminate this as a problem how can I test the valve? Does it work off 12v or a different voltage as it is controlled by the ECU?

If you press your petrol filler cap in, you should get a slight venting of pressure and a nice smell of petrol! This means that your fuel system is pressurised. If this does not happen, then you may have a slight breach on the system somewhere. Possibly on the pump or the pipes coming from it.
Also check that the fuel pipes to the filter and injector rail are not leaking. They are on push fit connectors, may need to be cracked and re-seated, or the o-rings replacing.
I had the fuel smell in the cockpit once on my 160, and also lost the pressure out of the system. Strangely after a couple of days, it sorted itself out.

Sundance

Fuel tank is pressurised- I replaced the filler cap o ring recently. There aren't any apparent leaks on any of the fuel pipes, but we all know how petrol vapour appears to get through joints where fuel won't. I've changed the fuel filter today, and next thing will be to gradually replace the spring clips on the breather pipe etc.

I'd still be interested to know how to test the purge valve if anyone has done this before? Is it 12v or less - I don't want to risk damaging it by applying the wrong voltage.

Continuing to try and sort this- looking at the tank pump I've noticed that the electrical connection plug on the top of the tank appears to have petrol gunge around the pins, so could it be leaking through the wiring connection? Has anyone come across this before?

I've not heard of leaks through the electrical connections, but the seal around there is a common source of leakage. Check the locking collar is fully tightened.

This is what the plug looked like before I took the pump out

When I took the fuel pump out, the pin you can see loose fell out

So it appears that at some time the pin has got hot ( I assume due to a poor electrical contact) and damaged the plastic holding the pin, leading to it becoming loose. So I've put shrink Insulation on the damaged part of the cable, polished the pin, and potted the cable pins on the inside of the pump lid with Araldite.
So once it is back together we'll see if that has sorted it.

thats a new one on me!

If you lubricate the seal before refitting, it makes the job much easier...

Thanks David. I'm going to use red rubber grease on the seal sparingly.

Dont forget to check the cable connector before re-assembling.

Will likely be in a similar "burnt" condition.

Also if poor connection caused the over-heating, then the pin connector (receptical) might be "oversized" and need squeezing together to re-gain a tight fit on the pin, otherwise same fault might return.

Dont want hot cables and petrol mixing!!!

Should be able to get a good second hand connector from MGFnTFbitz..

Sundance

SundanceUK wrote: Should be able to get a good second hand connector from MGFnTFbitz..

Sundance

Just carefully take the female pins out of the connector block, there’s a small barb just below the wire, clean em up and give them all a gentle nip, slip them back in and it should do job and you have nothing to lose lol..


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The pins will need to be cleaned carefully. Once burnt, the carbon deposits become conductive and may cause tracking. The plug is easily replaceable, the socket on the top of the pump is not. Really do your best to clean the socket before plugging the connector back in, and any further issues, I would either replace the socket if possible or renew the pump.
The cost of a second hand plug would be next to nothing, replacing the plug would be a no brainer for me.
As an industrial electrician, have seen many burnt plugs and sockets in my time. Nearly all needed replacing. The only good side is you are only feeding 12 volts (ish) to the connector, so tracking across any pins may not be as bad as the 24v that is the industry standard now.
The last thing you need is sparks and flames close to the fuel lines.

Sundance