No boost in my 20V rr ur quattro

[robbie100hp]

Iv been having some trouble with my quattro , it started playing up by stuttering under heavy load, then it started going into what I can only describe as a limp mode with hardly any boost but this would reset once I turn the car off then start it again, this only happens when I gave it a boot full, but it has got worse to the point that I can start the car floor it in first with full boost then half way up the rev counter in second the car will loose boost, the car has had a remap at some point not sure by who, it's got a straight threw exhaust with no cats a k&n and a forge splitter valve which how I know that it isn't boosting as much.
Any help would be great as I'm worried it will get to the point that I can't drive it any more

[K Simmonds]

Could be a couple of things, can you pull the fault codes? That's the place to start.

[robbie100hp]

I haven't got a lead or the software to do that, I know the ecu is under the centre console but where is the port?

[K Simmonds]

I'm not sure with a UR, if it's like a 3B S2 then the diagnostic wires will be dangling down somewhere under the dash on the drivers side. Will be three two pin plugs a black, a brown and a blue. Without diagnostics the first things to check for with those symptoms are boost leaks, ignition components and the MAF connector.

[robbie100hp]

Well it's had a brand new maf ,distributor cap, arm leads plugs, the power loss isn't all the time only under heavy load and not all the time. What's the best way of checking for boost leaks at home? Other than take all the hoses off!

[Monkeymagic]

You need a pressure tester which pressurises the system from the turbi intake pipe.
With the engine off you will/ should hear the leak. A spray bottle with soapy water will show any tiny leaks.,whats the forge thing you refer to. Try putting it back to standard.

[steverrquattro]

I would make up the lead which comprises of a diode and a resistor. It's a one off investment and I've used it so many times to diagnose faults on a number of cars.

Be sure to check the small vacuum hoses as well, especially the ones at the back of the inlet manifold.

[IshQC]

diagnostic plugs

the plugs are in the fuse box in the scuttle!

its bound to be a boost leak, sticky wastegate, forge valve packed up you've replaced most of the other bits so I would start there.

my rr did the same thing and it was the wastegate in the end.

[robbie100hp]

I don't understand what I'm supposed to do with a lead with a diode and a resister and how I can determine what is wrong sorry if I'm being a bit thick bit out of my depth, maybe should of stuck with my mk1 golf lol
The forge splitter is to replace the re circ valve, it recirc's some and dumps the rest like a dumpvalve

[Error404]

Get a 12v LED and come wire. Use the LED to blink the fault codes.You also need a short section of wire to bridge two connections to start the process. See here for how to make and use the code reader:

http://www.20v.org/fault.htm

Note the fault fault codes on that page are for the 7A engine and may not be applicable to your RR
Where abouts are you in the Midlands? Someone nearby might be able to help

[robbie100hp]

I'm in Cannock Staffordshire, who would be the best place for someone to look at it?

[simon20vq]

Why did you replace the maff, dizzy, rota, leads and plugs? Has it started playing up since you did that work?

[robbie100hp]

I replaced all of the above bar the maff as part of a huge service before I went to the ring in it, the problem has always been there since Iv bought the car but has got worse over about 6months. I drive it a lot harder than the previous owner and it's got 150,000miles on the clock. I always run it on high octain though

[Error404]

I'm in Stone so not far away. Away for a few days over Christmas but if you are still struggling after new year pop round we can read the codes and do a boost leak test

[K Simmonds]

It sounds like boost leak to me, especially as you've replace the other usual suspects. First thing I'd do is ditch the aftermarket diverter valve, was it fitted when you purchased the car.