Indicator Glows, Engine Hard to Start

CHECKING PENCIL-TYPE GLOW PLUGS AND THEIR LINES

Problem:
Preglow indicator lamp fails to light up when switching on. Lights up for approx. 1 minute while driving. Engine is hard to start. An open circuit of one or more pencil-type glow plugs or their lines to the pencil-type glow plugs is possible.





- Measure power consumption of the pencil-type glow plugs using the multimeter ampere measuring range and DC current probe. For this purpose place current probe over the individual wires on the preglow time relay.

Cylinder 1 = 2.5 black/blue
Cylinder 2 = 2.5 black/purple
Cylinder 3 = 2.5 black/red
Cylinder 4 = 2.5 black/yellow
Cylinder 5 = 2.5 black/green
Cylinder 6 = 2.5 black/white

- Turn key in steering lock to position "2" the power consumption for each glow plug should be 14-16 A after approx. 8 seconds.

- If the value is higher than 16 A, replace glow plug.

- With a value below 14 A, check wire and glow plug for open circuit.

- In order to check for an open circuit, pull 6-pin coupling off preglow time relay.





- With the multimeter ohm measuring range measure the resistance against ground (engine block) one after the other as follows:

Jack 1 of coupling = Pencil-type glow plug cylinder 1
Jack 2 of coupling = Pencil-type glow plug cylinder 2
Jack 3 of coupling = Pencil-type glow plug cylinder 3
Jack 4 of coupling = Pencil-type glow plug cylinder 4
Jack 5 of coupling = Pencil-type glow plug cylinder 5
Jack 6 of coupling = Pencil-type glow plug cylinder 6

- If infinite resistance is measured, an open circuit of the respective pencil-type glow plug or the feed line or the connection is the problem.

- Eliminate open circuit in the feed line or replace glow plug.