740 poor running and stalling

[Boatie]

Originally Posted by Laird Scooby

I fitted new "O" rings to mine on my last 740 Mark which did improve matters a lot. Full set of the 8 "O" rings from Volvo was about £17 although that's several years ago now. They're simple injectors, similar in principle to diesel injectors but obviously open at much lower pressures than the diesel at ~2800psi/200bar.

With that in mind there's less to go wrong on a K-Jet injector as it's much lower stressed in terms of pressure etc.

Please forgive someone who's last experience of a 740 was almost 20 years ago and who hasn't even read the full topic but here goes. Back in the 1990's when my B200e engine was ticking over really poorly I sought the advice of my local Volvo garage. The fellow looked, listened then wandered off. Couple of minutes later he returned, thrust some O rings into my hand and said words to the effect 'fit those and it will sort the problem'. He was right'

Still look back at that car with great fondness.

[Beadybc]

Originally Posted by griston64

That set won't fit if your car is K Jet. That is for later cars LH Jetronic

Did you put your VIN into Skandix ?

I did put in the VIN, was thinking that that set seemed to have more O rings than necessary.

And Boatie I wasn’t even born yet when that happened, let’s hope that we have a similar situation 20 years later.

[griston64]

Originally Posted by Beadybc

I did put in the VIN, was thinking that that set seemed to have more O rings that necessary.

And Boatie I wasn’t even born yet when that happened, let’s hope that we have a similar situation 20 years later.

4 of these https://www.skandix.de/en/spare-part...nkage/1000200/

and 4 of these https://www.skandix.de/en/spare-part...lower/1000201/

[Beadybc]

Originally Posted by griston64

4 of these https://www.skandix.de/en/spare-part...nkage/1000200/

and 4 of these https://www.skandix.de/en/spare-part...lower/1000201/

When the car gets back on monday I'll get my dad to have a look to see if the garage was actually telling the truth so we can decide whether new seals are needed and whether new injectors are needed as well. Thanks for the links.

[Laird Scooby]

Originally Posted by griston64

These ones https://www.skandix.de/en/spare-part...ector/1025659/

Try FRF to see how much they can get them for

Those are for the B27/28E K-Jet pre-1986 V6 Mark so they won't fit - also that's only one per injector, there's a second seal on each.

Originally Posted by Beadybc

Skandix says that part won't fit but this set will? = https://www.skandix.de/en/spare-part...ector/1078392/

Skandix are wrong - that's for the EFi models.

Originally Posted by griston64

This is K jet https://www.skandix.de/en/spare-part...valve/1014153/

That's the K-Jet injector Mark - even at that price only £200/Euro for a set of 4 but obviously needs the "O" rings.

https://www.skandix.de/en/spare-part...nkage/1000200/

https://www.skandix.de/en/spare-part...lower/1000201/

I think those are the "O" rings for the K-Jet injectors, one goes round that "dimple" in the middle of the injector, the other goes on the end.

Italian decoke definitely called for! What the garage have described as the problem with the injectors doesn't stack up either!

[griston64]

Originally Posted by Laird Scooby

Those are for the B27/28E K-Jet pre-1986 V6 Mark so they won't fit - also that's only one per injector, there's a second seal on each.





Skandix are wrong - that's for the EFi models.





That's the K-Jet injector Mark - even at that price only £200/Euro for a set of 4 but obviously needs the "O" rings.

https://www.skandix.de/en/spare-part...nkage/1000200/

https://www.skandix.de/en/spare-part...lower/1000201/

I think those are the "O" rings for the K-Jet injectors, one goes round that "dimple" in the middle of the injector, the other goes on the end.

Italian decoke definitely called for! What the garage have described as the problem with the injectors doesn't stack up either!

Just linked to those above Dave

[Laird Scooby]

Originally Posted by griston64

Just linked to those above Dave

Just found that Mark - some sort of go-slow meant those extra posts after the ones i quoted didn't show up until now!

Never mind, they certainly look familiar from when i did mine but i bought them from Volvo. I'll see if i can find the thread, had to use a drill stand as a press for one of the "O" rings both to remove the injector and "O" ring from the holder and also to fit the new "O" ring to the injector - more here :

https://www.volvoforums.org.uk/showt...injector+seals

Also (although the video no longer plays) the cam belt problems i had :

https://www.volvoforums.org.uk/showt...injector+seals

That was the cause of a lot of poor running on it!

Lastly, this was more of a tale of woe with some possibly useful upgrades as well as discussing the injector seals :

https://www.volvoforums.org.uk/showt...injector+query

Long time ago now, i've definitely been asleep since!

[Beadybc]

Originally Posted by Laird Scooby

Those are for the B27/28E K-Jet pre-1986 V6 Mark so they won't fit - also that's only one per injector, there's a second seal on each.





Skandix are wrong - that's for the EFi models.





That's the K-Jet injector Mark - even at that price only £200/Euro for a set of 4 but obviously needs the "O" rings.

https://www.skandix.de/en/spare-part...nkage/1000200/

https://www.skandix.de/en/spare-part...lower/1000201/

I think those are the "O" rings for the K-Jet injectors, one goes round that "dimple" in the middle of the injector, the other goes on the end.

Italian decoke definitely called for! What the garage have described as the problem with the injectors doesn't stack up either!

Exactly what my dad said: "It's funny how when I asked how the guys working in the garage came to that conclusion, the receptionist was suddenly an expert and knew exactly what the problem was without putting the phone down to ask them".

Hence why I'm not going to jump in and order anything yet. I might actually go back home on Monday and get some photos for you guys of the injectors and O rings. Any way I could test the injectors myself?

I've seen people using things like these: https://www.ebay.co.uk/itm/234053606...IAAOSwTWZg05Z4

But they all say that they're for diesel.

[griston64]

I think for the sake of £10 I would order the o rings from Volvo. It's a cheap enough thing to eliminate the potential issue

FRF will also give you a discount if you quote code C3

The part numbers are 947113 and 947115

Gotta be worth a try

[Laird Scooby]

Originally Posted by Beadybc

Exactly what my dad said: "It's funny how when I asked how the guys working in the garage came to that conclusion, the receptionist was suddenly an expert and knew exactly what the problem was without putting the phone down to ask them".

Hence why I'm not going to jump in and order anything yet. I might actually go back home on Monday and get some photos for you guys of the injectors and O rings. Any way I could test the injectors myself?

I've seen people using things like these: https://www.ebay.co.uk/itm/234053606...IAAOSwTWZg05Z4

But they all say that they're for diesel.

They are for diesel - the clue is in the pressure. Your injectors should open at 38-52psi (~2.5-3.5bar), most diesel injectors are about 2800psi or ~200bar so almost 100 times more pressure than your injectors need to open.

I seriously doubt they've even had the injectors out, you'll be able to tell by the lack of witness marks on the bolt heads securing the plastic holders and if the fuel is flowing around the injectors, it would pour all over the inlet manifold and onto the floor.

It's amazing how receptionists suddenly become experts on the subject you want to see someone "behind the scenes" for. Last time a receptionist asked me what it was in connection with i pointed out that firstly it was private and secondly if she had a hope of answering it, she would also be earning £100k a year as a GP and not sat on the reception desk.

I'm not normally that sarcastic but i'd had trouble with that particular receptionist more than once trying to prevent me seeing a doctor and it was way past time to explain things to her.