Roger Blassberg

Also known as X-relief relay. If this has failed you will lose headlights, wipers, heater blower and ABS amongst others. Best wishes RB

To get the performance out of a 16V engine, it really needs to be revved quite high and the gear ratios are designed accordingly with a reatively short final drive. And the fuel injection metering isn't very sophisticated to be honest. Particularly if your driving style is a bit "press on", you can't expect more than 30mpg average. But certainly, to answer your original question, the MFA should be within 2-3mpg of the actual figure unless the hose is leaking or the diaphragn sensor is defective. Best wishes RB

That's 30mpg as near as makes no difference which isn't a bad average. If your MFA says 23mpg, that is outside of the usual error range. On the other hand, the earlier 39mpg was too!! Check also that your brakes aren't binding; does it roll easily if you coast up to a set of traffic lights in neutral for example or are on a very gentle slope? Sticking calipers, especially on the rear, are an occupational hazard. RB

Firstly, what is your real mpg based on fill-up to fill-up? Has it really dropped or not? On your car I think that the MFA takes its mpg reading from a vacuum sensor connected to the inlet manifold via a small bore hose. If either of those is not airtight there will be an error; if it sees less of a pressure drop it will assume that the throttle is open and will give a correspondingly lower mpg reading. Best wishes RB

Stella, You will find second hand ones in the parts for sale or Cars for Breaking sections on here, but be aware that there are 2 types, "early" and "late" dependent on the age of your car. When looking at them , check that the reflectors , (the mirror surface inside the unit), are not corroded and that the glass front lenses are not chipped or frosted. You can get new lenses still I think, separately from the units. These can be fitted with a bit of patience. First things first, though. Check the input voltage at the connector to the bulbs; if it has dropped to below about 11 volts with the engine running, the wiring has become old and a direct feed via the relayed loom will probably sort the problem out

niedersaechsische Brotstange, left over from lunch at the Karmann factory........ RB

OK, having laid that one to rest, what ARE the causes of hot starting problems? Weak fuel pump, fuel filter, ?? I know that it's not injectors because they have just been cleaned. Maybe the temperature sensor giving too rich a mixture, but it runs really well and gives very acceptable consumption figures. Best wishes RB

That's useful information for me too!! It starts very well from cold, come Hell or high water, and settles to a very nice even idle, no missing or stuttering. But try to start from hot and it can take 5 seconds of cranking. I'll have a good look at the small bore hose and clips, then may need a pressure regulator. No doubt it is silly money............ Best wishes RB

Different control modules. The sunroof is controlled by the motor unit inside the roof-mounted switch/interior light cover. The sunroof symptoms you have are very common indeed, almost always with the slide function as opposed to tilt. The cure is usually to dismantle the sunroof and clean/lubricate the runners and the mechanism, and sometimes to replace parts. It is fairly straightforward but time consuming (at least it is the first time you do it!!) The spoiler is about the same story really; dismantle, clean, lubricate, re-assemble. Does it go fully up and down when the speed sensor tells it to? Best wishes RB

They tend to fail based on age rather than mileage, like most rubber or plastic parts particularly those which get very hot. And of course bad treatment such as pulling them off without the proper tool will damage them too. The damage you mention is probably about the worst place it could happen, as the weaker insulation is at the point where it is closest to an earth leakage path. Best wishes RB

This seems to happen only in warm weather or when re-starting a hot engine. The X-relief circuits (heater blower, windscreen wipers, ABS, headlights) sometimes, not always, remain isolated once the car has started and remain so for quite a while (many minutes). The problem can be temporarily fixed by switching on headlights and wipers and indicators and headlight flashers all at once for about half a minute. I have changed the x-relief relay.Not a solution. I noticed this problem first when I installed a relayed dipped headlight wiring loom. Any clever auto-electricians out there who can help, please. Have I upset things by changing the resistance of the headlight circuit through the switch as the circuit now only switches the relay rather than the full headlight load? I also disconnected the dim/dip resistor, the yellow plug in front of the battery. All comments greatly appreciated. RB

If it's anything like ATE 288mm single pot calipers, firstly get the piston out of the bore of the casting, then push the dust seal onto the piston and locate the front in the piston recess. Then pull the bellows to its fullest extension and locate the other end in the casting recess BEFORE you start to put the piston into the bore. Once both ends of the dust seal are located, then start lining up and pushing the inner end of the piston into the bore, lube with brake fluid to prevent damage to the main seal. I found that VERY gentle use of a large G-clamp/valve spring compressor to push the piston in the first few millimetres is useful - you need to start the main seal into the bore absolutely straight. I think that there is a lead-in. Best wishes RB

"Finger tight then back a 1/4 turn" is too loose. It should be just tight enough so that the bearing retainer plate washer can be moved sideways with a screwdriver without actually levering/twisting it against the recess in the disc boss. The bearing should be free to spin with next to no slack if you grab hold of the roadwheel top and bottom (jacked up) and rock it. Too tight and it will start groaning after a few hundred miles. Too loose and it will knock back the brake pads and give a soft brake pedal apart from anything else. (Just thought about this again, and of course it WON'T knock back the pads in a rear caliper because of the handbrake mechanism, but it may allow the disc to touch the pads and squeal) RB

Two N reg. withinn 10 minutes in North London. First is a regular spot, a beautifully turned out black one, slightly low , clear rear lights, reg N94 *** along Kenton Road to Northwick Park, just before 7 a.m., then a dark blue one in Greenford Road, Sudbury Hill heading northwards. Large diameter wheels. RB

Is the blue temperature sensor faulty - could be overdoing mixture enrichment even when up to temperature. How's the idle and fuel consumption? Best wishes RB

Clutching at straws here; I had a similar problem with my Passat a while ago; there was resistance to turning and lots of strage noises. It turned out that the rubber gasket in the bulkhead that the steering column goes through had got tangled up in the universal joint. It just needed to be re-located and all was well. Hope it's that simple.... Best wishes RB

The service I received from Mr Injector included changing the filters and seals (O rings), providing a before/after report on flow rates and ensuring correct spray patterns. I thought it was good value for about £70. a "satisfaction guaranteed" service is worth paying for. Best wishes RB

Jim, good to see you and the others as well. A thoroughly enjoyable time and interesting to put faces to names. I'm afraid I passed my old injectors on, but sets come up on eBay quite regularly. As said above, they are easy enough to fit. I took off both halves of the manifold and thoroughly cleaned out the injector ports using a very soft (brass) brush in the Dremmel. New gaskets for the manifold joints, and obviously new O-rings. All the best, Roger

Engine speed sensor fault will ALWAYS come up with the engine not runnining, so you can perhaps discount that. If it's running rich, it may well be the blue temperature sensor in the thermostat housing; this tells the ECU to richen the mixture when the engine is cold and should then tell it to revert to normal mixture once it gets to ( I think) about 70 C. It's cheap and easy (ish) to change that. What sort of fuel economy are you getting? Best wishes RB

Surely bags of potting compost if you want it to feel "planted"....... RB

I have only just picked this information up, and want to add my appreciation of Chris (RW1) Gaskell. His responses were always measured, reliable and a pleasure to read. I never met him in person, but there was a definite rapport through the medium of this group of like-minded enthusiasts. It sounds as though he was about the same age as me, which is cause for further reflection. I will do my best to be there for the tribute on Sunday at Stanford Hall. In respectful remembrance, RB

Are you losing coolant? Are your windows steaming up when the heater is on? If so, it's the heater matrix. Best wishes RB

Gents, The plastic ratchet thing is the bottom chain tensioner. The top one is hydraulic, the purpose of immersing/depressing the plunger in oil is to bleed out air but it will still need pumped oil pressure to exert its full influence on the top tensioner pad. Yours in pedantry (nothing to do with J. Savile) RB

The tensioner takes full pumped oil pressure (you'll see a little rubber o-ring somewhere on the top casing where it seals to the block, not to be forgotten during final reassembly !! ) so just soaking the tensioner in oil won't do it. There is a spring in there as well so that the chain doesn't go completely slack with the engine turned off. I'm sure that that bore has more than enough clearance now, but probably a bit low on compression....... RB

Well I was finally brought out of hibernation by the weather this weekend, and took out the driver's seat and carpet to follow the wiring, looking for the problem. Lo and behold, there was a break in the live feed, at a joint where it splits into two for each seat. This is under the carpet and had obviously got wet when the door membrane failed. The connector had totally rotted away, but fortunately the insulating loom tape had prevented the live feed shorting to earth. Anyway, all is now repaired and we have adjustable seats again. I took the opportunity to clean the (beige) carpets and plastic trim items at the same time whilst the seat was out. Incidentally, it's no wonder that modern (??) cars are so so heavy; an electric Recaro driver's seat in not a lightweight item!! Best wishes RB