I think Alan favours the Castle, Bob, or was it the Rose and Crown? :regular_smile: J.

Indeed chaps :-)

Not wishing to depart on too much of a tangent from Peter's thread, I do find the ULEZ piece perplexing. I have (this morn) discovered that of my seven vehicles only two are ULEZ compliant, and they are the two that produce the most pollution (by far): my 1976 Suzuki 2 stroke and the RB.

I'm not complaining, I just think it amusing the knots our society ties itself in.

Alan

PS. I've just checked the other vehicles and found that the Porsche is exempt from the ULEZ surcharge as well.
PPS. My Royal Enfield is also exempt the ULEZ surcharge (and the congestion charge - I'm guessing motorcycles don't pay that).

I really feel I've joined a knowledgable and friendly community here. Thanks a lot to everybody for all information so far supplied.

I've had injection vehicles before but mostly diesel, and in any case nothing has ever needed to be done to any of the injection systems. This K-Jetronic is rather complicated and I'm trying to educate myself so that whatever I do, I properly understand what I'm doing.

I am thoroughly confused by this continuous injection business. I understand that each injector squirts fuel 4 times per cycle, so it's injecting not only during induction but also during compression, combustion and exhaust. Is this right? It seems terribly wasteful of fuel yet it can't be or nobody would use the system.

Does anyone have a link to a free download of the K-Jetronic service manual? I found something online called Gasoline Fuel-Injection System K-Jetronic Technical Instruction but it was published in 2000 and probably has little to do with my 1978 system. And I have the Haynes but the troubleshooting and testing of the injection system is pretty sketchy.

Regarding ULEZ, there are quite a few classic car enthusiasts in the London Assembly which probably came in useful during the ULEZ discussions and voting. And there weren't, in the past, that many classics in London. Since the ULEZ expansion to cover most of London on Oct 25th, there are lots more, some of them pretty bad polluters like my friend's 1968 diesel Land Rover he bought to replace his non-compliant 1999 model.

I'm all in favour of ULEZ as London air is nasty stuff. But I (and every other motorcyclist) think that motorcycles and scooters should have been exempted altogether. There are no diesel bikes, yet, so bike particulates are very low as are the NOx emissions. The majority of the dreaded Uber Eats, Deliveroo etc scooters are newish and ULEZ compliant, and as these delivery scooters are three out of every four two-wheelers one sees, there were relatively few older but not yet historic bikes around. I'm pi-ss-ed off because I have a Honda VFR800i which I love, but it's non-compliant. So I bought a 1981 Moto Guzzi V50 Monza, which is also far from compliant but it is exempt. And yes all bikes are exempt fom the congestion charge, but good luck finding free parking in the centre since Westminer Council repurposed all the free bike bays. I always pretend to be a courier and park in some private office or hospital car park.

Well, I'll get on with the Volvo investigation and as I'm bound to have additional questions, I'll be back (as the man said)

If you follow this link you may find the Bosch K-Jetronic manual listed about half way down the page:

http://www.myvolvolibrary.info/Tech_files2.html

...or I think this link will take you directly to the document:

http://www.myvolvolibrary.info/Tech_..._Manual_EN.pdf

... I don't know about it myself (the RB has a carburettor), but it seems to explain how it works from first principles.

Alan

Thank you for the first hand account of the ULEZ. I can't imagine any circumstances whereby I would drive a motor car or ride a motorcycle into London, but it is nice to know what is going on in the country.

When I lived in the capital I was always amazed how it succeeded (pretty well) in getting 8 million people to live more or less harmoniously in such a small place, and at the same time still support itself and provide leadership for the whole nation.

Alan

I've just read through the Jetronic manual in a quiet period between walking Bob and my teenage son getting up (may be some hours yet) - and it is a pretty good read.

This seems to be answer to your question about the system injecting fuel on all 4 cycles (cut and pasted from the manual, in italics:

Mixture formation
The formation of the air-fuel mixture
takes place in the intake ports and
cylinders of the engine.
The continually injected fuel coming from
the injection valves is “stored” in front of
the intake valves. When the intake valve
is opened, the air drawn in by the engine
carries the waiting “cloud” of fuel with it
into the cylinder. An ignitable air-fuel
mixture is formed during the induction
stroke due to the swirl effect.

... so the system squirts fuel into the inlet tract continuously, and it is then drawn into the cylinder when the inlet valve opens during the induction stroke, einfach.

It looks simple enough - you should have that motor car of yours running well in no time.

Alan

I have been confused about that too. You have probably been thinking that "injection" meant that fuel is squirted straight into the cylinder, like on a traditional diesel. Obviously the timing of the squirt has to be intermittant but precisely timed each cycle. Also it has to be at a very high pressure to overcome the compression. So high that accidentally getting your hand in front of the injector while testing can inject fuel through your skin into the blood - very dangerous.
So modern fuel injection is not really "injection" at all - it's just a more efficient way of pumping petrol into the engine than a carburetor. It still actually is sucked in, rather than injected.

Hence it might just as well be fed continuously.

I would check out the cold start injector which can be removed to test. It operates for a maximum of 3 seconds whilst the starter is engaged the amount of time is controlled by the thermal timer. The control pressure regulator richens the mixture coupled with the auxiliary air slide but should not prevent the engine from starting.

That's an amazing resource. I had no idea it existed. Wow. Thanks ever so much, or should I say vielen Dank?

Peter

Great advice, will follow as soon as I'm at the car's location again. Thanks!

Peter