The UK quattro Network
This is here for completeness and to act as a future link for an extended debugging section - the WR can be a bit of a beast to diagnose. The classic mechanic's rule of thumb - fuel, air and spark - does not apply to the ur-quattro because the absence of a spark does not indicate a fault in the ignition system - it may be a deliberate decision on the part of the ECU. A better approach to diagnosing electrical faults in the WR's engine mnagement and ignition system will be found in the wiring section.
| Problem | Possible Cause | Tests | Solution |
|---|---|---|---|
| Vehicle will not accelerate at low revs | Idle switch defective | Check switch and wiring - Page 28-35 | Replace switch, correct wiring fault or replace wiring |
| ECU defective | Check ECU and power supply - Page 28-53 | Replace ECU, correct wiring fault or replace wiring | |
| Engine will not rev | Turbo defective | Check boost - Page 21-1 | Replace turbo |
| Wastegate defective | Check boost - Page 21-1 | Replace wastegate | |
| Inlet air temperature sender defective | Check inlet air temperature sender and wiring - Page 28-25 | Replace sender, correct wiring fault or replace wiring | |
| Idle switch defective | Check switch and wiring - Page 28-35 | Replace switch, correct wiring fault or replace wiring | |
| ECU defective | Check ECU and power supply - Page 28-53 | Replace ECU, correct wiring fault or replace wiring | |
| Idle at 1500 rpm | Idle switch defective | Check switch and wiring - Page 28-35 | Replace switch, correct wiring fault or replace wiring |
| ECU defective | Check ECU and power supply - Page 28-53 | Replace ECU, correct wiring fault or replace wiring | |
| Metering head or air mass sensor defective | Check paddle, plunger and CO adjustment | Replace defective parts | |
| Engine will not rev above 4,000 rpm | Idle switch defective | Check switch and wiring - Page 28-35 | Replace switch, correct wiring fault or replace wiring |
| Inlet air temperature sender defective | Check inlet air temperature sender and wiring - Page 25-25 | Replace sender, correct wiring fault or replace wiring | |
| Engine will not start | No power to fuel pump | Check voltage at fuel pump | Correct wiring fault |
| Check fuse for fuel pump | Replace fuse | ||
| Check fuel pump relay | Replace fuel pump relay | ||
| Fuel pump defective | Check fuel pump | Replace fuel pump | |
| Engine not airtight | Check breather hoses, oil filler cap, dipstick | Seal any holes found | |
| Distributor mis-aligned and timing incorrect | Check timing - Page 28-13 | Reset static timing | |
| ECU power supply interrupted | Check supply - Page 28-53 | Correct wiring fault or replace wiring | |
| Output stage TSZ switch defective | Check TSZ switch - Page 28-48 | Replace TSZ switch, correct wiring fault or replace wiring | |
| Distributor Hall sender defective | Check Hall sender - Page 28-41 | Replace Hall sender, correct wiring fault or replace wiring | |
| TDC (flywheel pin) sender defective | Check sender - Page 28-15 | Replace TDC sender, correct wiring fault or replace wiring | |
| RPM (flywheel tooth) sender defective | Check sender - Page 28-20 | Replace RPM sender, correct wiring fault or replace wiring | |
| ECU defective | Check ECU and power supply - Page 28-53 | Replace ECU, correct wiring fault or replace wiring | |
| Engine stalls or cuts out | Distributor mis-aligned and timing incorrect | Check timing - Page 28-13 | Reset static timing |
| Boost level too high | Check boost - Page 21-1 | Replace wastegate | |
| Faulty power supply to fuel pump | Check power to fuel pump | Correct wiring fault | |
| Check fuse for fuel pump | Replace fuse | ||
| Check fuel pump relay | Replace fuel pump relay | ||
| Fuel pump defective | Check fuel pump | Replace fuel pump | |
| ECU power supply interrupted | Check supply - Page 28-53 | Correct wiring fault or replace wiring | |
| Output stage TSZ switch defective | Check TSZ switch - Page 28-48 | Replace TSZ switch, correct wiring fault or replace wiring | |
| Distributor Hall sender defective | Check Hall sender - Page 28-41 | Replace Hall sender, correct wiring fault or replace wiring | |
| TDC (flywheel pin) sender defective | Check sender - Page 28-15 | Replace TDC sender, correct wiring fault or replace wiring | |
| RPM (flywheel tooth) sender defective | Check sender - Page 28-20 | Replace RPM sender, correct wiring fault or replace wiring | |
| ECU defective | Check ECU and power supply - Page 28-53 | Replace ECU, correct wiring fault or replace wiring |