Metal Tipped Injectors
***UPDATED BY TSB #259108.NOTE: Two types of fuel injector are used in these vehicles: Viton tipped and metal tipped. Viton tipped injectors can be used as a replacement for metal tipped injectors but only in complete sets. Check part number stamped on barrel of injector. Viton tipped injectors will have one of the following Bosch part numbers stamped on the barrel of the injector:
0-437-502-043 High pressure (replacement)
(Audi replacement, Part Number 035 133 551F)
0-437-502-044 High pressure (OEM)
(Audi replacement, Part Number 035 133 551F)
0-437-502-045 Low pressure (replacement)
(Audi replacement, Part Number 026 133 551)
0-437-502-046 Low pressure (OEM)
(Audi replacement, Part Number 026 133 551)
If injector has one of these part numbers, it is a "viton" tipped injector. Use testing procedure for "viton" tipped injectors.
CAUTION: Part numbers are for reference only. Always check with the your local Audi dealer parts pepartment for the latest information.
The fuel absorption characteristics of Viton requires different testing considerations than metal tipped injectors. This procedure applies to all Audi vehicles equipped with CIS fuel injection systems with metal tipped fuel injectors.
SET-UP
Fuel Pump Relay Socket Terminal ID:
1. To operate fuel pump when needed, remove fuel pump relay and connect remote switch to relay panel terminals 48 and 52 (see illustration).
2. Remove intake manifold upper section (if necessary).
3. Remove fuel injector retaining bracket and pull injectors from manifold leaving fuel hoses attached.
Comparing Injector Quantities:
4. Fix injectors into graduated cylinders or other measuring containers such as that shown in illustration. Be careful not to kink any lines.
Fig. 10 Special Tool 1348/1 Installation:
5. Place adjusting tool #VW 1348/1 on top of air cone (see illustration).
6. Back out adjustment screw all the way, push slide down to stop and screw adjustment screw in until magnet just contacts bolt at center of sensor plate.
7. Turn fuel pump "ON" with remote switch.
8. Back out adjustment screw on tool to slowly raise sensor plate until injectors just begin to release fuel.
9. Pull slide to the top position momentarily to purge any air from the injectors and lines, then push back down to stop.
10. Turn fuel pump "OFF" and pour fuel out of graduated cylinders into a suitable container.
IDLE QUANTITY - TESTING
1. Pull slide on tool up to first stop (idle position).
2. Turn fuel pump "ON" until any ONE cylinder is filled to the 20ml mark, then turn pump "OFF". Observe spray pattern from injectors while pump is operating.
^ A cone shaped mist of fuel should be sprayed from all injectors. Injectors that release fuel in a stream or droplets should be cleaned or replaced.
3. Compare fuel quantities in the graduated cylinders.
^ Injection quantity should not vary more than 10% from lowest to highest (all cylinders should be filled to between 18ml and 20ml).
4. Interchange the injectors that sprayed the smallest and largest quantities, purge the air from the lines and re-check.
^ If switching injectors changed which cylinders had the smallest and largest quantities, then one or both injectors should be replaced. (Injection quantity followed the injectors to their new location. For example, if cylinder #1 was the lowest and #3 was the highest, then after switching the injectors #3 is now the lowest and #1 the highest, then either or both of them are bad.) Injectors may deliver too little fuel if restricted, or too much fuel if valve tip or closing spring is bad. The injectors that deviate the most from the average quantity delivered, are faulty.
^ If switching injectors did not change which cylinders were the lowest and highest, then there is a problem in the lines between fuel distributor and injectors, or the fuel distributor is faulty.
FULL THROTTLE QUANTITY - TESTING
The full throttle injection quantity test is performed in similar manner as the idle quantity test, except that the air flow sensor plate is raised to the full throttle position and quantities are compared after delivery of approx. 80ml of fuel.
1. Raise air flow sensor plate to the full throttle position (lift slide on tool to top position).
2. Turn fuel pump "ON" until ONE cylinder is filled to the 80ml mark, the turn pump "OFF".
3. Compare fuel quantities in the graduated cylinders.
^ Injection quantity should not vary more than 10% from lowest to highest (all cylinders should be filled to between 72ml and 80ml).
NOTE: The fuel distributor control plunger can be checked for leaking while performing this test. Prior to checking injectors, remove air filter element from air cleaner box. When test is completed, check inside of air cleaner box for fuel. If any fuel is present, the control plunger is leaking into the air filter housing. The control plunger is not a serviceable part. If it is leaking, replace the fuel distributor.
INJECTOR O-RINGS (AIR LEAK TESTING)
1. Disconnect small air hose to intake manifold (air supply to air shrouded injectors).
2. Spray area around injectors with a mild solution of liquid dishwashing soap and water.
3. Connect air hose to air shrouded injector air supply port on intake manifold.
4. Regulate air pressure to 14psi (1 bar) gauge pressure and pressurize manifold.
5. Visually inspect area around injectors for bubbles. If any bubbles are present, the O-ring on that injector is leaking (un-measured air leak) and must be replaced.