740 poor running and stalling

[Beadybc]

Originally Posted by Laird Scooby

Great - did you check the cam timing mark aligned as it should as well?

Sorry for not posting for a while, I’ve just started my second term at University. Turns out the other day my dad arranged for the car to be looks over by a local garage and they’ve come back saying that they’ve found that the injectors are faulty and that is what is causing the poor idle. The only problem is that to replace the injectors they are asking for £500. I’m not an expert by any means but for new injectors and labour £500 seems a bit sharp. Any idea where I could get new injectors from?

I don’t think they could be cleaned as they’ve already had the methylated spirit running through them to no avail?

To remind you: 1989 740 B200E K-Jet

[Laird Scooby]

Originally Posted by Beadybc

Sorry for not posting for a while, I’ve just started my second term at University. Turns out the other day my dad arranged for the car to be looks over by a local garage and they’ve come back saying that they’ve found that the injectors are faulty and that is what is causing the poor idle. The only problem is that to replace the injectors they are asking for £500. I’m not an expert by any means but for new injectors and labour £500 seems a bit sharp. Any idea where I could get new injectors from?

I don’t think they could be cleaned as they’ve already had the methylated spirit running through them to no avail?

To remind you: 1989 740 B200E K-Jet

The meths isn't there to clean the injectors.

What evidence are they basing their claim on that the injectors are faulty?

[griston64]

Originally Posted by Beadybc

Sorry for not posting for a while, I’ve just started my second term at University. Turns out the other day my dad arranged for the car to be looks over by a local garage and they’ve come back saying that they’ve found that the injectors are faulty and that is what is causing the poor idle. The only problem is that to replace the injectors they are asking for £500. I’m not an expert by any means but for new injectors and labour £500 seems a bit sharp. Any idea where I could get new injectors from?

I don’t think they could be cleaned as they’ve already had the methylated spirit running through them to no avail?

To remind you: 1989 740 B200E K-Jet

You can send the injectors away to a couple of companies who charge £50 to clean all four and they also test the flow rate

£500 to swap the injectors is a total con !!

[Laird Scooby]

Originally Posted by griston64

You can send the injectors away to a couple of companies who charge £50 to clean all four and they also test the flow rate

£500 to swap the injectors is a total con !!

Very few companies will touch K-Jet injectors Mark.

[griston64]

Originally Posted by Laird Scooby

Very few companies will touch K-Jet injectors Mark.

You could email this company to ask https://www.injectortune.co.uk/Contact.html

[Laird Scooby]

Originally Posted by griston64

You could email this company to ask https://www.injectortune.co.uk/Contact.html

From their FAQ :

"Can you clean my injectors?

We can clean most petrol injectors, replacing used components with new where we are able to."

https://www.injectortune.co.uk/Faq.html

In their FAQ, "most" is underlined. Looking round the rest of their online shop, everything is EFi so i'd suggest they almost certainly don't clean K-Jet injectors. Presumably they have no way of opening the K-Jet injectors while ultrasonically cleaning them. I know these people don't clean K-Jet injectors for that reason :

https://www.emeraldm3d.com/emerald-s...ditioning.html

Opening pressure for the K-Jet injectors is 38-52psi which could be tricky (for many reasons) to create in a flow testing/cleaning bench as used for testing EFi injectors.

http://b2resource.com/PDFs/interjectKJetronic.pdf

More information there ^^^^^

[griston64]

So if the garage is quoting a price for four new injectors from Volvo £500 is about right ?

Not saying thats what needs doing for one minute but I can see where they get the price from

[Laird Scooby]

Originally Posted by griston64

So if the garage is quoting a price for four new injectors from Volvo £500 is about right ?

Not saying thats what needs doing for one minute but I can see where they get the price from

Probably about right Mark, not sure if they are even still available though. Maybe from GCP but i doubt they're a stock item.

I'm still not convinced it is the injectors, before the OP disappeared to uni again i was going to suggest adding an egg cup full of synthetic ATF to the tank which would help clean the injectors and revive rubber components in the fuel distributor while lubing the fuel distributor as well. It would also counteract any negative effects from the meths used for removing condensation from the tank. The other thing is, there's a strong chance the car actually just needs to be driven a fair bit. My gut feeling is that the problem is mainly lack of use.

[griston64]

Originally Posted by Laird Scooby

Probably about right Mark, not sure if they are even still available though. Maybe from GCP but i doubt they're a stock item.

I'm still not convinced it is the injectors, before the OP disappeared to uni again i was going to suggest adding an egg cup full of synthetic ATF to the tank which would help clean the injectors and revive rubber components in the fuel distributor while lubing the fuel distributor as well. It would also counteract any negative effects from the meths used for removing condensation from the tank. The other thing is, there's a strong chance the car actually just needs to be driven a fair bit. My gut feeling is that the problem is mainly lack of use.

Skandix list them with prices varying from about £50 each up to £96 each ( which could be gen Volvo )

I found an article from a guy with an old Merc that had the same injectors and he cleaned them up himself and fitted new seals ( like a big rubber bung ) and said it made a massive difference. They look pretty basic so I suspect you are right about that not being the main issue

[Laird Scooby]

Originally Posted by griston64

Skandix list them with prices varying from about £50 each up to £96 each ( which could be gen Volvo )

I found an article from a guy with an old Merc that had the same injectors and he cleaned them up himself and fitted new seals ( like a big rubber bung ) and said it made a massive difference. They look pretty basic so I suspect you are right about that not being the main issue

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.