J.R.

As usual the slow drip drip feed of relevant information finally reveals itself. We can now deduce that the vehicle is under warranty and that the OP is being given the run around probably by the dealer who sold him the car and who is responsable, binning him off to a warranty company who have no incentive whatsoever to fix the fault and who have a contract with Halfrauds to carry out inspections and to say there is no fault. If you bought the car recently and it is still under warranty put pressure only on them, its not your job to be proving a Halfords employee wrong, just that your car is not functioning correctly. That said it would have been more honest of them if they had simply said, "the wipers work on slow and fast, we are not spending any time or money on an erratic single sweep function, - sling your hook!"

If you cannot access VCDS its a relatively cheap thing to do as it is effectively a dry break coupling so you do not lose the refrigerant when swapping it out, access is usually tight though. They were a common failure point on earlier cars, water would gather on top and corrode the housing releasing the crimped seal, a small amount of refrigerant would leak and corrode the terminals. The modulating valve can be hot wired for test purposes, swapping that out loses all the system contents.

Surely you must be more concerned about them breaking into your house for the keys? That should be the focus of your security measures. Are they really breaking into houses to steal a 21 year old small hatchback?

I understand. In which case I commend you to the latching relay and momentary pushbutton as the system is auto-arming so you wont forget or get fed up with setting it. The relays I used were tiny and the pusbuttons equally so as the body and button would pass through a 6mm fixing hole.

I ask myself what your reactions would have been in the not so distant days of vehicles with points ignition, distributeurs, carburettors and manual chokes to an idle speed variation of about 50rpm, I know what the reaction of the garage would have been!

ECU failure translates as "if its not what I suggested (cam/crank sensor) then I havn't an effing clue so I will tell you it's the most expensive thing in the hope that you take it somewhere else".

Divorce.

In terms of security what you are proposing is of little value compared to the RFID coded chip in the ignition key. You say "we all know these things can be bypassed", what do you know that I don't? I know that if your keys or spare keys are stolen then the robber can drive away with your car, I know that if they can get their hands on them for long enough they can be cloned but otherwise nobody is going to drive of with your car even if they break the steering lock. Back in the pre 95 days when RFID immobilisers were not mandatory I created a more user friendly and discreet method of immobilising my cars than a hidden switch although circuit wise thats what it was. I used a latching relay with a tiny momentary pushbutton hidden above the steering column behind the dash panel (the cars were 7's so you could reach underneath when belted in without anyone realising), turn on ignition and the coil & fuel pump circuits were isolated, push button and shout "Contact!" like Biggles and the engine would start and run. No procedure to follow when switching off, just remove the keys as normal & the relay would isolate the circuits and energise a flashing LED, if you stalled the engine it would restart as normal with no faffing around, the important thing is that you dont have to remember to arm the system and give away the switches location by doing so. For motorsport the external cut out switch can unlatch the same relay but covering all circuits in that application. Far more reliable as the switch was then only carrying the relay current and not the full cranking and charging current which oxidises the cheap contacts, they were a major source of breakdowns. The system was also very good for highly tuned engine running a lot of static ignition advance that would either crank very slowly or kick back, you could spin the engine up and then spark up the ignition like Biggles.

Most people do not melt my headlamp fittings, in fact nobody has to date.

Given the symptoms its unlikely to be the wiring but every chance that it is the canbus node contained within the motor, mine did very similar weird things before changing the motor unit, I had freed the brushes and the motor spindle a couple of times, that always resolved the slow running or sticking but the crazy behaviour was the controller within the unit.

Mine on the Yeti were absolutely fine and then within no time at all the car was pitching violently on undulations ate autoroute speeds, before the suspension was so stiff that I could not do a bump test on the front without bending a wing, even on the bonnet slam panel I could not exert enough force, when I tested after noticing the pitching it wallowed up and down with zero damping, they were completely shot. Its a testament to the vehicle that in normal driving I had not noticed, the same happened when a rear anti-roll bar link detached, I was completely unaware of that one having already changed the front struts.

Probably the G65 modulating valve, might be the pressure transducer not reading the pressure. If you have access to VCDS you can look for the compressor shut down code which may say something like low pressure if the sender is foutu. If there is no shut down code and it shows the modulating valve being actuated and a corresponding compressor torque (which will be fantasy) but no cooling of the evaporator then its either the G65 valve, the pulley shear plate or stripped plines on the alloy hub.

I had a V64V engine in my Sierra XR4x4, gods truth! It didn't make a noise like that, in fact it didn't make any noise. From memory it was destined for a Le Mans C2 car, I was asked to be the wheel man because the Sierra was a company car and my fuel was paid for, pretty sure the whole deal was very dodgy. I mentioned on another thread that I had worked on the design of the 6R4 but it resulted in the person who started the thread about his car getting antsy, it repiqued my interest and Google brought me the first reference I have ever seen to the work we did at IAD back then, posting it on this thread hopefully will be more appropriate, my memories of the reasons for the late and hurried redesign were correct: "From here radiated all the enthusiasm that was to make it happen. Gordon Sked’s styling people got us fixed up with IAD down in Worthing to make a proper styling buck. IAD created the information needed to produce all the fibre-glass and Kevlar panels. But even then there always seemed to be a new spanner dropping into the works. Not the least of these came when Pierre Dupasquier and Maurice Guaslard at Michelin, with whom we had been working closely since Day One, suggested that perhaps we could move up from 13-inch wheels to 390mm and thus benefit from all the work they had been doing for Peugeot What they meant was that we had to do it or be stuck on non-development rubber. It meant that engineer Wynne Mitchell could incorporate bigger brakes, but the original arch profile had to go as he and Richard Hurdwell lifted the suspension turret tops and lengthened the wheelbase by two inches. Looking back, it seems almost a miracle that, over the winter of 1984/85, everything came together. The V64V ran after just 11 months and delivered on its promises. The changes to the suspension and bodywork to accommodate the big Michelins were handed over to IAD, while the final form of the outrageous front and rear wings was agreed. The Longbridge line was geared for action and the Radford plant identified as the best location for engine and gearbox assembly. My task was to put together the final presentation to the ARG Board in the middle of January. Their approval would set everything in motion, and with help from Fred Coultas, the paperwork was done, the figures added up and the methods detailed. To my immense satisfaction, it was agreed: our target was the 1985 RAC Rally."

Morally though, what you say, correct as it may be legally, is very poor form especially after the parts bingo the OP has played trying to avoid doing the very thing that they have paid him £800 to do at his request.

How long have you owned the vehicle and when did the problem manifest itself? What work was done before the problem? Air is being drawn in to the fuel line which is either a leak or a flow restriction, reversed connections to the fuel sender unit will cause the latter and in my case provokee the former on the seals of the fuel filter cartridge. The connections have different colours but interchangeable, the photo in the Haynes manual was black & white & made it look like the connections should be reversed, they may even have done so themselves before taking the photo, it can take months before an airleak manifests, the pump has to work much harder but does overcome the non return valve just, in doing so it creates a considerable depression across the filter and supply line.

I have a pressure brake bleeder which uses a similar dry break coupling, my stuff is stored in several locations and I have no idea where it is to check it. What are you trying to achieve?

Have you removed the tank sender unit recently? Mistakenly reversing the feed and return lines will give the problem you have.

I think this is the one you have: https://alltradedirect.co.uk/collections/airline-hoses-couplings/products/euro-air-line-adaptor-high-flow-female-coupling-1-4-bsp The coupling: https://alltradedirect.co.uk/collections/airline-hoses-couplings/products/euro-air-line-high-flow-female-coupling-1-4-bsp-fmthfcf

This looks to be the same as the ones that I have although I havn't measured them, dose it look the same as yours? https://www.continental-industry.com/en/solutions/fluid-handling/industrial-vehicles/chassis-body/couplings-quick-connection/products/product-range/flat-face-quick-connect-plug-in-couplings

It is the Continental equivalent of the PCL airline fitting, I have loads of them in my spares box as my airlines use PCL connectors so I swap them. I also have several of the couplings All airtools sold in France at the Brico-sheds use them.

I have an O ring splicing kit, had it probably 20 years now and not actually used it yet but one day it is going to be worth its weight in gold.

I concur, I fear this saga is only going to get worse. Dowding, what remedial action were you intending taking with the £800 from the reduction that you negotiated?

I have that affect on people!

My engine has done 110K miles & I think had a hard life for 80K before my ownership, it does not use a drop of oil between oil changes, no smoke visible on my test but I really should do it on a hot engine and remove the cap totally. I will repeat the experiment in the week but for now I would say pulsating positive pressure if not normal is not causing any ill effects on my engine.

Guess what! I tried it, there was positive pressure, the cap was jiggling up and down like the OP's, maybe not quite as bad but I didn't want to take my hand away as it was blowing out millions of dead mosquitos that had taken their last drink from the spillage ring, I did not want any to get in the engine. In future I will make removing the cap with the engine running part of my maintenance regime to blow away any muck and foreign bodies which might otherwise get in during an oil change.