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I'm just putting it out for discussion and stand to be corrected. I have the Bentley as well and all the VAG service manuals for the VR. The Blue sender is linear because the senders all use the same design. It doesn't need to be I believe. The other variations re temperature come from the intake sender which measure the temperature of the air in the throttle body ( which is cooled by the coolant). Cooling and fuel injection are two separate but related systems that interact with each other closely. The ECU controls fuel delivery only, it has no control over the cooling system and only uses various temp related inputs from it and the O2 sensor (lambda) and the TPS etc. The VR looks complicated at first, but Bosch Motronic is a relatively simple system with only a few inputs to the ECU from the various senders compared to more recent systems on modern cars. You are way more likely to have a wiring fault, short in the loom etc than a dodgy sensor with a car this age.

It's only a linear reading because that is how that particular temp sender design works. The blue one only needs to read hot or cold. The problem is people buy cheap ones or use second hand ones - but always worth testing before doing the work. I tested a new one from VAG and it was duff, my original one was fine after 20 years or more, and with cheap ones you take your chances. IMHO only.

There's a simple test with a multimeter and a bowl of boiling water. If the sensor is not working the ECU doesn't switch from cold to warm running map - hence the poor emissions. When cold, all bets are off on emissions figures.

There are: ECU coolant temp for fuel cut-over - BLUE - stat housing Inlet Manifold Air Temp Sender - goes to ECU also Radiator temp sender - BLACK - for the fan controller module Yellow/Black/Brown - in stat housing, these are for the dash coolant temp gauge, air con and secondary fan controller The "definitive VR6 cooling thread" that's a sticky on here has all the info you need to check out your system is working properly as designed. Use the search, Luke. ;)

ECU coolant sensor rarely goes in my experience - that's the blue one. But cheap to replace if it hasn't been done - buy VW, Bosch or VD0. The inlet manifold temp ones are a piece of **** and a bad design. I've heard of people moving them to the airbox for better readings. The stat has nothing to do with fueling.

VCDS and a diagnostic cable were the best money I ever spent on a mod! My stalling at junctions when returning to idle was solved by a clean of the throttle body and a lube of the accelerator cable and checking of the TPS stop adjustment by the way. The ECU temp sender is the blue one - all it does is tell the ECU when the engine is warm enough to switch from rich to normal fuel mode - nothing else. It is also used for starting, but doesn't make a difference really. The gauge and fans run off the other sender, secondary controller for aircon etc on other cars off the third. They all function the same way so you can actually swap the cabling around to test them. Never use second hand ones - they aren't that dear and don't need to be replaced that often. The ECU will do a soft reset when the battery is disconnected for more than 10 minutes or so - changing a sender does not require the full reset procedure, it will simply relearn the stored values. it doesn't have its own battery or anything. Just my experience with this kind of thing. You can end up spending a lot of money on unneeded parts if you don't do proper diagnostics.

Blown or leaking heater matrix - don't have a passenger in the car when it's like that. It will end in tears.

I went H&R as well with B6 dampers - no problems at all on a 93 VR.

Early and late VRs had different spring lengths, even though they were both "PLUS" 5-stud wide-track suspension set-ups. Mine is a 93, and was noticeably lower than any later 94 or 95 cars I've seen, and that was on stock suspension with 35K miles on it when I bought it. If you check the parts list, you'll see that the shocks are more less the same but the springs differ in length, and the part numbers are different based on chassis number. The spring plates were then also changed - that's your mystery there - after-market suspension suppliers don't cater to this difference and only offer 4-stud or 5-stud set-ups (normal or Plus Achsel) for Corrados and Mk2/3 Golfs because it doesn't make sense for them to manufacture parts for all the variations. This is why the front spoiler also changed in height from 90 to 50 mm on later cars - customers felt the car sat too low and the spoiler was rubbing on the ground. That's my two cents input into this particular classic VW mystery anyway.

You might be able to come across the repair kit for the guides and cables if search ebay etc. - or replace the sunroof altogether with a Monroof from a B4 Passat.

Excellent stuff. I have a thread on here about my fuel pump and pressure saga so it will be interesting to compare the part numbers. I knew about the gauge sender float problem.

Was available new from VW Classic Parts quite recently, or I'm sure you will find some second-hand ones on here - the problems is that they are very fragile, get brittle with age and all tend to be cracked or broken after 20+ years.

Earth wire shorting or disturbed during the respray. Check all wiring or bring it back and ask them to fix it.

Ditto - and did you replace the lead from the ignition amplifier to the dizzy as well? Sometimes it gets forgotten. No harm sticking a new rotor arm in there as well.

All normal. Just make sure your cooling system and fans are functioning as they should. There's a very good VR6 cooling thread on here. Check out the first few posts in it.

Me too

Should be able to get the Bosch one for about half that.

Or you might have a leaking hose or feed line or a faulty FPR.

You should fit a non return valve on the feed hose just above the pump in the boot. If you search my old threads for fuel pump and pressure on here there's loads of info and links. Btdt

Great stuff

Are your injectors leaking or have worn seals? Not sure about the voltage, but maybe your engine is flooding. You should also have about 3 to 3.5 bar residual pressure at the rail after an hour so of the engine off. It could be a dodgy ECU but maybe the injectors open when there is no voltage? I'm not sure.

Lemforder and Febi are both good. OEM suppliers. I believe.

OE or ATE discs and pads all the way for a daily imho

Squeeze them hoses!

Please let me know details.