Removing, installing and checking injectors and constant pressure valves — AUDI

AHU
Special tools and workshop equipment required

Ring spanner 3035
V.A.G 1322 with V.A.G 1322/2
VAS 5051 with VAS 5051/1 and VAS 5051/2

or

V.A.G 1551 with V.A.G 1551/1

Note:

Defective injectors cause the following problems:

Loss of power
Excessive formation of black exhaust fumes
Increased amount of blue smoke on cold starting
High fuel consumption
Overheating of engine
Knocking in one or more cylinders
Misfiring

Defective constant pressure valves cause the following problem:

Uneven idling (possibly sporadic)

Removing

Use open ring spanner 3035 to unscrew injector pipes.

Note:

Always remove entire set of pipes. Never alter shape.

Unfasten nut, detach retainer and take out injector.

Note:

Make the following tool to deal with seized injectors:

Saw off injector pipe approx. 5 cm after injector union nut.
Attach M6 nut to sawn-off section of pipe by brazing.
Thoroughly clean improvised tool as dirt would render injector unusable.

Screw union nut of improvised tool onto seized injector and apply special tool 3364 at brazed-on nut.

Installing

Note:

Always replace copper gasket between cylinder head and injectors.

Insert injectors.
Make sure mounting brackets are correctly positioned in cylinder head.
Insert retainer.

Tightening torques

Component · Nm
Injector pipes · 25
Bolt for retainer · 20

Checking

Reading measured value block 13
⇒
0.82 mg/S
-0.12 mg/S
0.49 mg/S
Read measured value block, Display group 013, engine idling => Page 01-77.
Specification: -1.50 mg/S ... +1.50 mg/S (milligrammes per stroke)

If one or more specification(s) is/are outside tolerance, interchange injectors (with the exception of injector for cylinder 3).
If error accompanies injector, replace injector.
If error remains with cylinder, check compression.

=> 4-cyl. Diesel Direct Injection Engine (TDI), Mechanics; Repair Group 15; Removing and installing cylinder head; Checking compression pressure
4-cyl. Diesel Direct Injection Engine (TDI), Mechanics
Removing and installing cylinder head
Checking compression pressure

If compression is OK, replace corresponding constant pressure valve -arrow- with sealing ring.
Tightening torque: 45 Nm

Notes:

Use soft object (plastic, wood) to remove sealing ring from pump, as otherwise sealing surface could be scratched.
As of a mileage of 15 000 km the full set of constant pressure valves is to be replaced.

This engine features dual-spring injectors. The quantity of fuel is thus injected in 2 stages.
In the event of problems with such injectors, replacement is the only course of action, as neither pressure adjustment nor servicing is possible.

Check injectors with V.A.G 1322 and pressure pipe V.A.G 1322/2.

Attention:
When checking injectors, make sure fuel jet does not strike hands, as the high pressure would cause it to penetrate the skin and possibly result in serious injury.
Checking spray pressure

Pressure gauge switched on

Slowly depress pump lever. Take spray pressure reading on commencement. Replace injector if spray pressur deviates from specification.

Specification
New injectors · 190...200 bar
Wear limit · 170 bar

Leak test

Pressure gauge switched on

Slowly depress pump lever and maintain pressure of approx. 150 bar for 10 seconds. When doing so, there should be no dribbling of fuel from injector orifice.
Replace injector in the event of leakage.