I said i'll be back!

[Laird Scooby]

After much blood, sweat, tears, swearing, caffeine, nicotine and various prescription drugs also ending in or containing "ine", cogitation and machinations and other stuff too, with the help of my mate i eventually got the fuel tank swapped for the new one today. While it was (eventually) out, i renewed the two hoses i suspected of leaking and sure enough, they were perished/cracked on the ends i couldn't see. In fact on the rigid pipes you can see where the underseal has been washed slowly but surely away by escaping 98 octane!

Anyway, the new tank is now in and after much fighting with the in-tank pump/sender unit i finally managed to ram it all the way in and screw up the locking ring. There is evidence on the tank to show petrol has been leaking in that general area as well from above the point where it would have been if it was leaking from the hoses that attach to the pump/sender unit so either there is a hairline fracture around the mounting collar the locking ring screws onto or the ring wasn't tight enough beforehand.

Rain and bad light stopped play quite late in the evening, still got the hoses to reconnect and also the electrical connections. I'm confident it's fixed the leaks and the "petrol pong" though!

I swear the fuel tank and it's mountings, level sender/in-tank pump unit etc was designed by a mushroom growing gynaecologist!

Half the time you're in the dark getting covered in sh!t, the rest you're through a small hole feeling your way to the right spot!

I did manage a couple of pics, still got to upload them so watch this space!

[Laird Scooby]

Pretty pictures and update time! While i wait for Photobuck-ay to load, i'll do some words.

It's nice not to get into a car where the air is higher octane than most pump fuel! The leak seems to have gone and early indications, based on the amount of fuel i put in, a subsequent top-up of a smidge under 4 gallons and my knowledge/experience of how the gauge behaves (when it works!) suggest i'm getting somewhere between 26-31mpg.
Of course the proper method is full tank to full tank but for now i'm rebuilding trust in a leak-free fuel system!

Here's the access hatch under the boot floor :



New and old tanks side by side :



The feed and return rubber hoses where they join the rigid pipes above the diff nose cone :



Note the lack of/discoloured underseal on the rigid pipes!

The rigid pipe end of the return hose - difficult to see but it's perished and cracked :



Similar but the feed hose - easier to see the cracking/perishing :



I think it's fairly easy to see why it was using so much fuel and smelled like the pit lane at Silverstone! Also there was some evidence there was a leak from the tank just below the collar where the locking ring screws onto the sender/pump unit.

In other news i did a very basic test to prove it is livelier without the viscous fan on. I haven't got the final result yet as i'm waiting for a friend to come over and pilot the stopwatch but it appears to have made a significant dent in the 0-60 time. When i first got the car, after doing a few basic things (oil/filter change etc) it would do it in 9.93secs. Not bad for a 28 year old, heavy, automatic!
However it's a fair bit livelier now. Initial figures suggest about a 10% quicker time, however that was with me operating the stopwatch on my phone (cradle mounted of course Ossifer! ) and as it was passing 60 it was pushing me into my seat so effectively i struggled to reach the stop button. As such i was doing nearly 70 before i stopped it.
I'll report back once my friend has timed it with his phone as that was the original method - consistency and all that!

While on the subject of the vicious fan, the economy certainly seems better without it although for the most part it had the fuel leaks as well so difficult to say exactly except i saw figures between 22-35mpg before xmas on different runs, 22mpg for general pootling around the village, 27mpg on a fast motorway run and 35mpg on a gentle A-road run but still at 60mph ish.
If those initial figures are right, 26-31 is a definite improvement, have to do a longer run soon to see what it's doing.
Also the auxiliary electric cooling fan (for the air-con) only comes on when idling or slow driving on a hot day, rarely while moving at a sensible speed on the open road.

Next trick are the HID conversion bulbs for the fog and driving lights followed by the new front pipes aka the Holy Grail as they are about as hard to find as a hens dentist!

[Paul240480]

Loving the updates, keep 'em coming

Peebucket.... Make sure you keep your original pics. I didn't keep all of mine.... Well, they were on an old knackered PC and never got round to getting them off, thinking I had them on Peebucket.... You can guess what's coming....yep Peebucket lost the lot, no explanation other than they had a glitch and mine was one of 'a few' accounts that were hit. All not recoverable. 10yrs worth of pics and threads like this one ruined.

Please back up , if you haven't already , hope not a sucky-eggie post.

[Laird Scooby]

Hmmm, i remember that "glitch" and i was one of the lucky ones, didn't lose any.
I suppose i should invest in a USB drive and copy all my photos from my PC onto that as well, then i can empty out various folders etc on my PC and also my phone to create some new space and speed them up a bit.

The updates will most certainly keep coming although because i think i've either inspected or renewed almost all the problem-prone parts now, hopefully it will be more along the lines of upgrades/improvements and/or routine maintenance, possibly with an LPG conversion thrown in at some point as well. Might do a separate thread for that though. Still deciding whether to go single point mixer or Sequential Gas injection (SGi) for the LPG, i've got a single point on my Rover 827 Coupé and while it works well enough, because of the variable length inlet tracts on it, it can throw the mixture into confusion under certain conditions (hoof buried in the Axminster, up-change under kickdown from 3 to 4 or cruising in 4th/top with about 4000rpm on the tacho and squeeze a bit hard on the loud pedal) so that will be coming off my Coupé at some point.
The 760 doesn't have variable length inlet so it shouldn't be a problem but the lure of injection is definitely there!

[AndysR]

Nice work there, sounds like you've taken your time and been patient as it sounds like a fiddly job, could you see most of the fuel leak issues when you removed the inspection hatch? Thinking about checking mine after seeing this, although I don't have the issues of fuel smells aa you've described so hopefully they're ok. What made you change the whole tank? Is there a fault with the tank, you may have mentioned it previously but I don't remember you mentioning it specifically.

Interesting about the performance, can you physically feel the difference in performance now when driving the car? I find the best way to time the 0-60 is to set up a camera and film the speedo then you can watch back and time it against the length of the video between 0 & 60 mph
Do you think the auxiliary fan can cope to control the engine temperature long term? I wonder how hot the engine has to be before it cuts in? I know mine works as I've tested it manually but even yesterday with the engine idling after a motorway run the fan didn't cut in, but you could hear the viscous was engaged and could feel the warm air being blown out from under the car. Then there was the brief roar from the fan on initial acceleration that went by the time the trans shifted to 2nd that's the most I usually notice the viscous fan when in operation

[Laird Scooby]

Thanks - most of the fuel leaks were invisible. Except by witness marks on pipework and on the tank. Sounds obvious but unless it's a major leak, the petrol evaporates as it leaks so it's hard to see, especially in this warmer weather.

As for why i changed the whole tank, i had my suspicions about it, it had to come out (for access to the feed/return hoses), there was a new tank available on ebay so the slightly facetious answer is "because i could".

However, there were marks under the collar where the locking ring secures the sender/pump unit that suggested fuel was escaping and running down.
These marks originated above where they would have been if the seal was leaking. This led me to believe there is possibly a hairline crack around the collar at some point.

There's definitely more urge to the way the car performs and even on the hot days we've had recently, the fan hasn't cut in that often so i suspect the auxiliary fan will cope, at least until i get the air-con sorted out. One day when i get a spare 10 minutes i'll take the infra-red thermometer and monitor the temperature until the fan cuts in.

[bluebrickrick]

Thats just where I hit mine with the back of a 9 lb felling axe Dave, have you checked the HP pump area for wiring shunts where one end of a crimp connector isn't crimped ??????????

Your description of the specialist techniques needed remind me of the turbo oil return pipe grommet, which also includes operating in braille

I'm interested in the limited slip fan replacement as it seems to be working hard.........

Rick

[Laird Scooby]

A potted history of "Pong-gate" Rick :

December last year, bought a new fuel filter as my guess was it still had the factory original. Weather/health prevented fitting until later.

February this year - i start smelling petrol, at first only on the over-run but later all the time.

March - when that yellow thing appeared in the sky and started warming things up, the smell became more permanent. About this time i was able to crawl under and renew the fuel filter and that's when i started finding the leaks.

Since then it's been a case of finding the leaks by elimination, all of which were down to the age of the rubber hose, except perhaps for the link pipe between the main pump and the filter which looked like it had been damaged at some point. The link pipe is still available new from Volvo - for £49 if you feel rich! I simply cut the nylon tubing off with a Stanley knife and replaced it with a loop of 6mm bore fuel hose to make fitting easier and if the ends do perish and leak again, there's enough there to chop them off and remake it without a problem.

After replacing all the rubber hoses i could see, i found it was still smelly. That's when i pulled the access panel up and had a look and found the two hoses (feed/return) feeding from the tank to the rigid pipework. I could also see the witness marks from where something, presumably petrol had run down the outside of the tank.

The only hose i haven't renewed (but i did snip the perished end off and remake it) is the return line from the fuel rail to the rigid section under the bonnet. Again it was perished at the end but seems ok further back.

At the moment i'm still using the (semi-redundant) auxiliary cooling fan from the air-con for cooling purposes, it only seems to come one after being in traffic or slow driving, occasionally after a fast run when i've dropped down to crawling speed.

[AndysR]

Originally Posted by Laird Scooby

A potted history of "Pong-gate" Rick :

December last year, bought a new fuel filter as my guess was it still had the factory original. Weather/health prevented fitting until later.

February this year - i start smelling petrol, at first only on the over-run but later all the time.

March - when that yellow thing appeared in the sky and started warming things up, the smell became more permanent. About this time i was able to crawl under and renew the fuel filter and that's when i started finding the leaks.

Since then it's been a case of finding the leaks by elimination, all of which were down to the age of the rubber hose, except perhaps for the link pipe between the main pump and the filter which looked like it had been damaged at some point. The link pipe is still available new from Volvo - for £49 if you feel rich! I simply cut the nylon tubing off with a Stanley knife and replaced it with a loop of 6mm bore fuel hose to make fitting easier and if the ends do perish and leak again, there's enough there to chop them off and remake it without a problem.

After replacing all the rubber hoses i could see, i found it was still smelly. That's when i pulled the access panel up and had a look and found the two hoses (feed/return) feeding from the tank to the rigid pipework. I could also see the witness marks from where something, presumably petrol had run down the outside of the tank.

The only hose i haven't renewed (but i did snip the perished end off and remake it) is the return line from the fuel rail to the rigid section under the bonnet. Again it was perished at the end but seems ok further back.

At the moment i'm still using the (semi-redundant) auxiliary cooling fan from the air-con for cooling purposes, it only seems to come one after being in traffic or slow driving, occasionally after a fast run when i've dropped down to crawling speed.

Is the cooling fan live at all times or does the a/c need to be switched on? I can't remember from when I tested mine whether I switched the a/c on or not. I know the a/c doesn't work just wondering if the system needs to be electrically live in order for the fan to work. Pretty sure from the way it appears to be wired it doesn't, just curious to know if it's worth having the a/c on when in traffic to assist the viscous or not.

[Laird Scooby]

As far as i know the aux fan is fed with an ignition switched feed Andy but whether the A/C system needs to be powered up (even if it doesn't work) to actually control the fan on/off i don't know. Someone has added a relay that is switched by the sensor in the rad on mine but they've also removed the evaporator and all the gas from the system!

You'll probably find if your A/C doesn't work then the fan won't come on when the A/C is switched on, just the green flashing snowflake to show a fault on the ECC panel.

I know that's probably not helpful but as there are bits missing from mine it's tricky to know how it should work if it's complete and working or not as the case may be.