Glowplug operation

[wizard101]

The glowplug light on the dash of my 94Mav only illuminates for 3/4 seconds. I understand from other postings that it should stay on for about 15 seconds when starting from cold. I have looked at the two glowplug relays behind the battery and there is no sign of damage - but then why does it need 2 relays and what determines how long they operate for? I also saw a reference in a posting to a water temperature sensor associated with the glowplugs - how does this operate? Has anybody got a wiring diagram for the glowplugs on a 94Mav?
Peter

 

[rustic]

Hi My 95 mav light illuminates for 4 seconds from cold, just tried it now, not been run for 24 hours. (In a garage though).

When warm they illuminate less, I guess when really cold it is on for much longer.
Hope this helps.
regards,
Rustic

 

[mav]

Hello there.

I know its not a Maverick, But Nellies been stood overnight and all day. Stuck her up at about 5pm, Glow plug light was on for 3/4 seconds max too.

Mav.

 

[CHASTER]

Hi wizard101.
Most Terrano / Mav glow plug INDICATOR LIGHTS glow for only 3 to 4 seconds. Why do you mention the subject? Are you having starting problems?

 

[wizard101]

Hi Chaster,
The engine starts but takes 5/10 seconds of cranking and then not all cylinders fire. Also lots of blue smoke. After a couple of minutes runningm everything settles down, smoke disappears and we're off. So I thought Glowplugs. Looking at the manual pages for the TDi (but mine is a 94 TD) I see that the check of glowplug operation on a cold engine says that the plugs should be energised for 20 seconds. Now the TDi has a different glowplug control system than the TD (I assume) but I am still expecting that on a cold morning (and we have had a few recently) the glowplugs would be on for 15 seconds or thereabouts - sure I saw this figure in a previous post. Mine come on for 3-5 seconds. When I look at the glowplug relays I can't find any timing device - and why are there two relays?
Glowplugs themselves check out OK.
Fuel heater connection to fuel filter housing has been disconnected - don't know if this matters.
Any info appreciated.
Peter

 

[rustic]

A similar condition occurs when there is air in the system.
When I changed the fuel filter a few months ago I bought a cheap one that didn't seal properly and there was trouble starting and all sorts of coloured smoke, white, blue. black so I bought a nissan one. Problem solved. I also filled the filter with diesel before installing as suggected by another member, (saves using the manual pump too much).

The heater in the fuel filter must serve a purpose ! (More on cold days I guess) I wonder if you had a new fuel filter recently and this got disconnected during the installation.
Do you know the history?

 

[wizard101]

Fuel Heater now reconnected. Wires had broken off at the unit so had to remove the whole thing and solder them back on. Checked that there is electrical continuity through the heater - showed 5 ohms on the meter - so seems OK. There is another connection to the fuel filter mounting which is on the same wiring plug as the heater. This is a brass fitting with two wires coming out of it. I had to take this out to take the stuff indoors to solder it. Seems like this must be a heat sensor - nothing on the inside when you take it out except a flat bottom which sits in the fuel supply.
Anyway, all this seems to make no difference at all now it is re-connected. I checked with the meter and didn't find any voltage on the heater either when starting or with the engine running. Temperature in the shade at the time was 1C after a very cold night so either its not working or its intended for Arctic conditions.
I did a fuel filter change recently and checked the filter after Rustic's comments. Didn't find any sign of anything amiss.
Oh how I wish I had a wiring diagram for this machine!
Peter

 

[rustic]

Oh how I wish I had a wiring diagram for this machine!
Peter

Your wish is my command.........

try this link... http://bebrs.pie-dabas.net/Webs/Terrano/R20/fwd.pdf

have a good look through there is a wiring diagram somewhere...

Plus LOTS and LOTS of info...
This will keep you happy for a few hours.. :lol: :lol:

 

[Toolbox]

wizard101,

Have you connected a voltmeter to the glow plug supply and turned the key on to see if there is any voltage and how long it is on for?
I am no 100% sure but you should find a controller behind the ashtray area, that deals with this and the egr, a sort of engine ecu.

 

[wizard101]

Thanks for the reference to the manual Rustic. I have looked at this thoroughly - it is the manual for the later model (post'96?) TDi and while it is generally useful, the glowplug/fuel heater/engine control arrangements are completely different on the TDi to the TD - unfortunately.

Toolbox - thanks for the suggestion. Just before I tear the console out, can you confirm that this controller was present on a '94 TD and not something that came in with the later TDi.

Thanks to all
Peter

 

[Toolbox]

I am pretty sure the TD has a type of ecu and presume it works the glow plugs, I have never had the need to search it out and am not 100% on its location. So it will be up to you to trace it down and let us all know.

I would test the voltage supply to the plugs first as I think you should find the glow plugs continue to work after the light has gone out.

 

[mad-mike]

Hi all,

Just checked in the manual that i have and i think the glow plug control unit is on the o/s under the trim panel by the accelorator pedal (i think) on the 2.7td.

I'm having a similar problem with mine and cant find the fault, so i gave up after hours of fruitless investiagtion and made my own 'glow plug system' up unitill i can have another go at it. Not quite nissan standard but it works well as long as you remeber to turn the plugs off once you have started it.

Mike

 

[CHASTER]

Hi again wizard 101.
Sorry for delay in this follow up.
I too was surprised that my glow plug ind light only stayed on for 3 to 4 secs. and engine needed plenty of cranking if I tried immediately after light extinguished. Also, engine was smokey and erratic when it did cough into life.
Tried a different tactic which works for me.-------
Switch off all noisy bits ( heater fan, radio etc.) and ask wife to stop talking :smile:--- then turn ignition switch on and after glow plug light goes out switch ignition OFF and listen carefully for relay, near accelerator pedal, to click off (it's fairly quiet and might take 7/8/seconds or so). When it clicks off , quickly turn ignition on again and let glow plug light operate another 3 to 4 secs THEN, when it goes out, IMMEDIATELY crank the engine.
Works like a charm on mine every cold morning, even when it's minus 7C.
Good luck.