UR Quattro Set Up?

[twoqu]

The popping in the inlet manifold possibly sounds like a timing issue. Double check the flywheel window, the cam pulley dot/cam cover and the dizzy marks ensuring its on No1 compression stroke.
As you have said, if you have fuel and sparks then the only other thing would be a massive vacuum leak from somewhere either the hoses or injector O rings or a mechanical problem.
You could verify its fuel related by squiting easystart into the inlet. If it starts then its fuel related.
I had a non start 200 that I eventually traced down to low voltage at the ecu which was caused by the earth strap connected to the cam cover. If you can find a pin out for the relevant ecu then that might be worth a check.
I know the car run before and you have done nothing more than theoretically improve it, which makes it that much more frustrating!

[Monkeymagic]

I have checked banjo bolt it's not a restricted one. WUR was rebuilt also. Timing is absolutely smack on. I think the popping in the inlet is down to the cold start injector floodingbthe manifold from repeated cranking. I have come up with a couple of other ideas. I'll keep you posted.
I still keep coming back to the previous owner has connected the feed and return lines back to front . they have been replaced from the tank. I can't find a flow diagram,but etka seems to suggest I may be on to something. I really hope it is that simple. I did replace the injector seats and and seals along with the new injectors as the spray pattern was awful..
I'll give the easy start a whirl, I hate that stuff but it will point me in right direction as you say.

[newsh]

Any use?
Schematic is from the Audi 200 Haynes
The other 2 from a copy of the original WR workshop manual

[Monkeymagic]

Thanks Newsh. I swapped the lines at the metering head today. Needless to say it only sprays fuel with downward pressure on the air flap. ( don't panic it was very very light)
I swapped the lines at the unions near the strut so at least now the lines are correct as per the manufacturers intentions. However if I crank if over I was getting no fuel from the injectors indicating poor vacuum.
I took the TIP off and had a friend crank it on the key. There was very little if no vacuum. So clearly there is a leak...

In the absence of any easy start I bridged the fuel pump and lifted the air flap, I get a lovely atomised spray of fuel, clearly the K jet repairs were worth doing. However price still no start.

I went back to check the spark, I'm now getting a spark from each plug in order, however the spark is not coming from the electrode to the ground, it strays from the insulation to the adjacent part of the ground.

I tried another plug and grounded it on a stud in the head. THat plug gave a good spark..
However the plugs are new Bosch times from Quattro Corner at considerable expense. I'm starting to feel like this car may beat me at this rate.

I certainly don't think it's a wasted spark as its at all plugs. II I pull the coil lead I get a great fat rhymical spark, suggesting all is well with it. I had a friend crank it over while I very slightly moved the dizzy to see if the dizzy timing was fractionally out. I have checked static timing a million times so know it is right.

I clearly have two issues, 1, no vacuum at TIP! 2, A very odd spark that randomly won't work..
I can test for leaks easily with my pressure tester but the spark is twisting my melons now.

[twoqu]

Are the plugs fitted resistor type? Are they single electrode?
Might be better to post the type unless you have done so before.

[Monkeymagic]

I can look at the receipt from Pete Reeves.. I know they are Bosch single electrode

Hang on grey are W4DP0 plugs

[twoqu]

I believe that is the correct plug spec for the WR.
Whats the difference between the plug that works correcly and those?

[Monkeymagic]

To be honest I'm not sure, I'll have a look at what plug I used when I'm next there later in the week.. It's all very very odd.

[newsh]

UR Quattro Set Up?

Could it be a bad ground somewhere?

Engine earth strap good?

Timing 360 degrees out?

Bad rotor arm? (sparks at plugs should be as fat as they are from the coil)
A bad rotor arm can short or partially short the spark down into the shaft of the dizzy

[Monkeymagic]

Tonybolony has suggested an earth issue. It has crossed my mind too. I will check the body to gearbox earth strap, however if this was bad I would expect the starter motor to be lazy.
The plug leads are magnecor ones from Pete Reeves and I have a spare lead as a tester which is a known good one. I may well try a new rotor arm, although I did test it and it checked out.
The spark from the coil is fat and regular suggesting the fault isn't with the engine sensors/coil.

[Tonybolony]

Internal crack/split in the rotor, causing (most of) the spark to go to earth?

[twoqu]

Hmm.. if it was not for the fact that another spark plug has a good spark we could have pointed the finger at either the rotor arm/cap/leads. Certaintly the factory leads should have a certain resitance in total and thats what the end caps produce, think its 6K in total, 1K from the dizzy connector and 5K at the spark plug. I seem to recall that when I tested some Magnecor leads the resistance varied depending on the length of the cable.
If you tested that other plug with the spare OE lead that might explain it.

[twoqu]

Of course just because the plugs are new doesen't mean they are not faulty or damaged. I also seem to recall that the plugs fitted to the equivelent spec 200 engine of the same vintage (KG) were just ordinary and not the platanium ones specced for the UR for some reason. Might be worth trying to source an equivelent cheap set just to prove the car can start.
Rereading the above it does sound like the insulation is cracked on the plugs which allows the plug to track. I would carefully inspect the insulation for cracks.
Frankly its either the leads or the plugs.

[chezz]

Firing order? I assume you have the correct sequence...sometimes overlooked

[newsh]

There should be a braided ground strap from the cam cover to the coil bracket.

Otherwise if the dizzy is timed on number one compression stroke (not exhaust stroke) and sequence is good then

Internal crack/split in the rotor, causing (most of) the spark to go to earth?