Genuine Audi 90 Distributor

Audi 90 Distributor Parts and Q&A

• Distributor Assembly
  034-905-237-AX
  Q: How does a Distributor affect the procedure for using a stroboscopic timing light to check and adjust ignition timing on Audi 90?

  A:

  The procedure requires a stroboscopic timing light to be performed. The first one is to start the engine until it reaches normal operating temperature. The second step is to shut the engine and attach the timing light as per the instructions of the equipment manufacturer. In engines with DZ, PM, and JN disconnection and plugging of the vacuum hose at the distributor should be done; in all other engines the hose should be left unplugged. Next, switch on the engine and operate it in idling mode and align the timing light by passing through the timing window on the left side of the clutch housing. When the ignition timing is right the notch on the flywheel will be at the lower part of the window. In case this needs to be adjusted, take the tamperproof top off the distributor clamp bolt, loosen the bolt, and turn the distributor as required. Once the adjustment is complete, screw the bolt and replace the cap. Connect the vacuum hose again where necessary, switch off the engine and take out the timing light.
• Distributor Assembly
  034-905-237-X
  Q: How to properly remove and reinstall the distributor while ensuring the engine is at TDC compression on No 1 cylinder on Audi 90?

  A:

  Prior to the distributor being removed, locate the engine at TDC compression with No 1 cylinder, by removing the spark plugs and rotating the engine clockwise by using a spanner on the crankshaft pulley bolt until compression is detected in the engine. Turn until the TDC marks are on the crankshaft pulley and lower timing cover and the corresponding mark on the flywheel is in line with the corresponding mark on the transmission housing (20-valve engine). To further check it the upper timing cover may be opened to position the TDC mark on the camshaft sprocket in line with the pointer on the 20-valve engine or the upper edge of a cylinder head on other engines. Properly identify the distributor body and engine block or cylinder head relative to the other with a scribber or pin punch, and remove the vacuum pipe attached to the vacuum capsule on the distributor, where applicable. To change the connection, squeeze the spring clip in order to unhook the wiring plug, peel off the interference screen, where fitted, and lift the cap off the distributor by pushing open the clips. Test to see whether there is a mark on the upper rim of the distributor body at the center of the rotor arm; otherwise, mark with a pencil. A special tool can be employed to align the rotor arm on the 20-valve engine, or a tool can be made out of card, or a former distributor cap. Unscrew the clamp bolt or nut to take off the clamp, and then take out the distributor out of the block or head. In the case of the distributor, check the condition of the rubber O-ring on the bottom and replace it where required, and the gasket in the distributor where present. Make sure that the crankshaft is at the TDC point and position the rotor arm a little clockwise of TDC and align the distributor with the aperture with the block or head made marks. Slide the distributor into place with the rotor arm positioned anti-clockwise back to its starting position as the drive gears slide in place. In case the distributor does not fully fit in the four cylinder engine, withdraw that distributor and apply a screwdriver to turn the oil pump driveshaft a bit more, before attempting to fit. Once the alignment of the marks has been established, attach clamp and fasten bolt or nut, replace the distributor cap, wiring plug and vaccum pipe, and timing cover (unless removed). Lastly, verify or correct check the ignition time where needed.