Changing GLOW PLUGS on 1992 300D 2.5 Turbo.... any advice ?

[kamil]

Hey.

I need some advice on changing GLOW PLUGS for a 92 300D turbo. From the looks of it I need to take off the intake manifold . Wondering if there is a way to bypass that pain in the butt procedure. Is there anything that I should know about changing plugs ? Any type of special grease ? Anything ?


Thanks

[DieselAddict]

The intake manifold has to go and yes it's quite a lot of work. Are you sure your glow plugs need replacing? If they test ok with a multimeter there's no reason to replace them.

[speedy300Dturbo]

Originally Posted by DieselAddict

The intake manifold has to go and yes it's quite a lot of work. Are you sure your glow plugs need replacing? If they test ok with a multimeter there's no reason to replace them.

It's not very hard as long as you have the proper tools. I recommend using a 1/4" drive allen socket (3/8" is a bit bulky) with a swivel or two, and a fine toothed or gearless ratchet. A magnetic pickup tool will be useful if you drop one of the bolts.

[McDiesel]

I hava a mechanic in Hammonton new jersey who can change them for you without removing the manifold.. he has EYES in his fingertips

if Interested heres his number 609-561-2616 there are only two wrenches there Rob and EDDIE ask for EDDIE it may be worth your ride down the turnpike for the one or two hours labor <64 dollars is his rate> They are partners and own the shop .. so there is no bosses around and they are really laid back located right off of the white horse pike in hammonton on wiltseys mill road if your using mapquest for dirs

Tell him jeff told you to call ... of course the car would need to cool off for him to get to the last glow plug which is the hardest to get to but he has always gotten them out without effort and without removing the manifold..
while your there he can also clean out your crossover pipe with his parts washer// just did min on my 1990 and 92 turbos.. man that soot looked like
coal in there..

i think it would be wroth the hour or so drive!

[kamil]

MCDIESEL,

When you put your key in the ignition and preglow the plugs without starting the car does your GLOW PLUG light come on ? Mine only comes on after starting the car.

thanks

[McDiesel]

It could be one of two things.. you either have a bad glow plug or two or your glow plug relay has died...
usually when the pre-glow light is lit AFTER you start the car it is one or both of the above conditions.. the light will usually go out in a few mins.. do you get a rough idle in the first 15 seconds or so of staring.. again another indication of a failed glow plug or more than one or a combo of both..

the glow plug relay is simple to change out but it runs about 140bux or so so i would at least have someone like my pal eddie in hammonton put his ohm meter on the plugs 1-5 and see which one is the culprit.. if he gets a good reading on 1-5 then chances are its the relay..

I had one go in my 1990... it wasnt the glow plugs. there are just two screws
on the relay i believe.. you cant screw it up!

btw he only works m-f 9-5

good luck!

[McDiesel]

Indicator Does Not Glow, Engine Starts OK

TESTING BULB AND ITS WIRING//////// NOTE YOU ONLY HAVE 5 CYLINDERS!
If the following problem occurs:
Preglow indicator lamp does not light up when the preglow system is switched on, despite being able to start engine.

Detach 6-pin connector from preglow time relay, turn key into position "2", bridge contacts 1 and 3 of the connector. If the preglow indicator lamp does not light up, test bulb or replace if necessary.
If the bulb is in order, test black cable from connector contact 3 of the preglow time relay to the preglow indicator lamp for open circuit. Rectify open circuit.
If the preglow indicator lamp lights up, the preglow time relay is defective. Replace preglow time relay.
If lamp shows a steady light. Preglow time relay defective (relay sticking).

Indicator Glows, Engine Hard to Start

TESTING GLOW PLUGS AND THEIR WIRING
If the following problems occur:

Preglow indicator lamp does not light up when switching on.
Lights up for approx. 1 min . when driving.
Engine is difficult to start.
There may be an open circuit in one or more glow plugs or in the cables to the glow plugs.

Test current consumption of the glow plugs with multimeter set to Amperes range and with D.C. clamp. The clamp is placed over the individual cables at the preglow time relay for the step.

Cylinder 1 = 2.5 black/blue
Cylinder 2 = 2.5 black/violet
Cylinder 3 = 2.5 black/red
Cylinder 4 = 2.5 black/yellow
Cylinder 5 = 2.5 black/green
Cylinder 6 = 2.5 black/white <----- YOU DONT HAVE THE SIXTH
Turn key in the steering lock to position "2", the current consumption of each glow plug must be 14-16 A after 10-12 seconds .
If the reading is higher than 16 A , replace glow plug. If the reading is less than 14 A , test glow plug cable for open circuit.

Detach 6-pin connector from preglow time relay for testing for open circuit. With the multimeter set to Ohms range, measure in turn the resistance to ground (engine block) at
1 Connector = glow plug cylinder 1
2 Connector = glow plug cylinder 2
3 Connector = glow plug cylinder 3
4 Connector = glow plug cylinder 4
5 Connector = glow plug cylinder 5
6 Connector = glow plug cylinder 6 <------ YOU DONT HAVE THE SIXTH



If infinite resistance is measured, there is an open circuit in the respective glow plug or in the lead or the connection. Rectify open circuit in the lead or replace glow plug.
SAFEGUARDING PREGLOW CIRCUIT

An electronic short-circuit safeguard is installed in the preglow time relay. The circuit is interrupted if a short-circuit develops in the glow plugs or in the cables.

THE RELAY IS AGAIN OPERATIONAL

Once the short-circuit has been rectified and
The key turned back to position "0".
TESTING TEMPERATURE SENSOR WITH WIRING
Preglow time until preglow indicator lamp goes out is too short or too long (refer to table). Detach plug on preglow time relay and test F resistance to ground F with multimeter set to Ohms range.

Specification:
at +25 °C 2442 ±170 omhs
at +180 °C 291 ±16 omhs

If specified value is achieved:
Replace temperature sensor.

If resistance infinite ohms is indicated:
Rectify open circuit in cable.

If resistance < 1 ohms is indicated:

Rectify short-circuit in cable.

Preglow System . B
. 0.3
. 0.5 LABOR RATE MAN HOURS TO TEST

Notes ::

If the following problem occurs:
Preglow indicator lamp does not light up, engine cannot be started.



With the multimeter set to the Volts range, test the voltage at terminal 30 of the preglow time relay to ground (arrow).
If no voltage is indicated, test 4 mm red cable from terminal block (X35) terminal 30 to the preglow time relay terminal 30 for open circuit. Rectify open circuit.
If no fault has been detected to this point, test voltage at contact 1 of the 6-pin connector of the preglow time relay to ground.
MODEL 124



Test pink/red cable from fuse 7 (unprotected side) through plug connection of engine wiring harness to the connector contact 1 of the preglow time relay for open circuit. Rectify open circuit.
If voltage is indicated, connect multimeter Volts range to contact 1 (terminal 31) and test voltage. If no voltage is indicated, test brown cable from contact 4 to ground for open circuit. Rectify open circuit. If no fault has been detected to this point, the preglow time relay is defective. Replace preglow time relay.

[kamil]

thank you

[McDiesel]

anytime bruddah~~

good luck...

cheapest fix is hoping its just a bad plug.. i always have 3-4 on the shelf..

seems like i blow one evey winter... use of the block heater helps if you have one!@!