Well i got this funny 'um coming from my rear........
 

It's a bit strange, i've owned the car nearly 3 years now (1988 760GLE B280E LH2.2) and not heard this before.

Having gone through a lot of diagnoses on a few other things, something became very obvious, the in-tank pump wasn't pumping.

Thankfully the other problems were all sorted and many improvements have been made, however there was still a niggly little fault that shouldn't have been happening, that of slight hunting on idle after braking on a downhill then turning into a car park - or any similar situation.
By keeping a reasonable amount of fuel in the tank i'd kept rolling through but it was begining to niggle at me, mostly that the underbody pump isn't man enough to pull a head of vacuum to lift the fuel from the tank. I knew if i didn't replace the in-tank pump sometime soon, i'd be replacing both pumps at the worst time possible.

Cue a visit to https://www.rockauto.com/ and a few days later, an Airtex pump and strainer landed for the princely sum of £35.59 including S&H (USA version of P&P), Customs Import VAT etc.

Waited until the weather improved and i felt up to attempting Volvo Gynaecology Masters Level and then fitted it.

It's cured the hunting after braking downhill and also (unexpectedly) improved throttle response. Since i've had the car it's always felt as if it needs a 2 minute warning of impending beans being given - now i know that there was momentary fuel starvation until the fuel was pushed to the back of the tank giving the underbody pump enough of a boost for it to do its thing.

However, the fuel rail is still dropping pressure overnight so i also ordered one of thse today :

https://www.ebay.co.uk/itm/BOSCH-Dis...9/173415230965

https://i.ebayimg.com/images/g/z9oAA...w6K/s-l400.jpg

Description is slightly wrong, it's the underbody/main fuel pump output check valve according to the Bosch part number and photo. If my theory is correct and the existing one has failed/gone weak (after 31 years and 225k miles i think it probably has!) then it's allowing fuel pressure to drain back through the filter, main pump and back to the tank through the in-tank pump while the engine is off.

Once it arrives i'll report back but hopefully it will restore instant firing hot or cold (hot starting is improved since the new in-tank pump went in, still not perfect though) as soon as the starter hits the flywheel.

Bottom line is the "funny 'um" is the soothing sound of the in-tank pump doing what it says on the tin! :thumbs_up: ;) :D

Glad you got it sorted Dave!

Brilliant diagnostics as usual, hope the new check valve solves the starting issues.

Thanks Luke, for now it still needs the "starter flick" then start and it fires instantly. Time will tell once the new check-valve is in place! :thumbs_up:

The check-valve from the ebay seller didn't arrive. :realmad:

After a bit of digging, i found the Volvo part number Fuel Pump Check Valve 1326899 - Bosch 1587010539 and have ordered one from GCP via my local Volvo dealer for a few pence over £26 (£26.16 rings a bell but mioght have been £26.61) which will be here in about 2 weeks time.

I've found several across the planet, mostly in the USA where they can be had for as little as $12 (£10) but the killer is the S&H (that's P&P to us in the UK) that seems to be ridiculously high at about £20 - higher than a set of handbrake shoes from Rock Auto or the previously ordered in-tank pump and strainer from Rock where S&H was about a fiver.

Again, once it arrives and is fitted, i'll report on the result. :thumbs_up:

At least you will get you £10.63 back from eBay. That guy in Reading seems to be a 'little' low on the ratings at 98.4%. Look forward to your update. Bob :)

As it happens Bob, i had a few stray sheckels in my Paypal account when i first bought it Bob so that has been refunded already, the balance which came off a card is on it's way.

You confused me with "Reading" - because i'd started a request, i had got more used to seeing these details (copied from the bottom of the listing) :

Business seller information
Max Car Parts Ltd
Raman Kapur
Unit 6 Britannia Industrial Estate, Dashwood Avenue
High Wycombe
Buckinghamshire
HP12 3ES
United Kingdom


Seems even the seller doesn't know where he is, never mind the item! :eek:

At least ordering through the local Volvo dealer now, i'll get a text or a phone call when it lands from GCP and i can then have a nice little drive out to collect it. :thumbs_up:

Yea Dave ... didn't bother gong into the minutia like I would do if buying. Reading/High Wycombe all about the same!! :)