L322 4.4 tdv8 glowplugs not glowing

kermit_rr · Feb 21, 2023

It seems they still arent working

I'd found the connector that does to the plugs was slightly unclipped, so checked/cleaned and reseated the connection. went through every connector I could find, unclipped, checked for corrosion etc and reconnected.. no joy.
if i get in the car when its fully cold, foot on brake and press/release the start button, it cranks without waiting for the plugs to warm and the warning light doesnt come on the dash, not even for 1/2 a second, then it runs lumpy and smoky for maybe 1/2 a minute and settles down, so the plugs are clearly needed.
SDD reports no engine error codes, the garage checked and saw no errors either so I'm stumped.
They did work just fine, then the fan and tensioners were mucked about with and the top of the engine cleaned (wiped, not steamed/power washed) so could well be something still dislodged but no ideas what.
Not sure if its related, but on the last start, I noticed regular loudish clicking from the front of the engine, passenger side, right at the very front where the big pipes go to the radiator. I'd say it was the radiator clicking at the very top, but the fan doesnt appear to be catching anything and its the wrong frequency, maybe 2 times a second. Any ideas? its not the fuel heater, thats much further back, maybe even under the slam panel?

Mark Piercy · Feb 21, 2023

If you can get to the plugs or at least one. Setup a dvm and se if there is 12v at that glow plug fitting on a cold startup. If so then you may need to check the resistance of each plug.
If nothing at à glow plug fitting they may not be needed due to the coolant temp?

kermit_rr · Feb 21, 2023

resistance was checked where the loom plugs into the 2 glow plug relays by the garage, was deemed OK
i dont think theres any chance of getting to the plugs themselves without taking the inlet manifold off, there a lot of rubbish in the way

Mark Piercy · Feb 21, 2023

kermit_rr said:
resistance was checked where the loom plugs into the 2 glow plug relays by the garage, was deemed OK
i dont think theres any chance of getting to the plugs themselves without taking the inlet manifold off, there a lot of rubbish in the way

If they been verified then maybe not the issue. Where the relays checked also for output?

kermit_rr · Feb 21, 2023

Mark Piercy said:
If they been verified then maybe not the issue. Where the relays checked also for output?

no, no clue how to do that

DanClarke · Feb 21, 2023

Maybe the temp sensor has failed and reports that Glow-Plugs aren't needed (even though they are)?

kermit_rr · Feb 21, 2023

DanClarke said:
Maybe the temp sensor has failed and reports that Glow-Plugs aren't needed (even though they are)?

i thought that, or maybe unplugged (reading +35c?) but the temp gauge on the dash works normally. could there be a second temp sensor that doesnt affect the dash gauge?

DanClarke · Feb 21, 2023

kermit_rr said:
i thought that, or maybe unplugged (reading +35c?) but the temp gauge on the dash works normally. could there be a second temp sensor that doesnt affect the dash gauge?

We need a @Saint.V8 on the case.

kermit_rr · Feb 21, 2023

an alternative test i did, when i expected the glow plugs were needed, watched voltage drop as I turned the ignition on.
there was no change in battery voltage to suggest the plugs had come on then switched off, like you would see when you turn the lights on/off etc

badfluffy · Feb 21, 2023

kermit_rr said:
i thought that, or maybe unplugged (reading +35c?) but the temp gauge on the dash works normally. could there be a second temp sensor that doesnt affect the dash gauge?

there are 2 on the jag petrol engine, one for the ecu and one for the gauge which only has 3 positions cold normal and oh ****

DanClarke · Feb 21, 2023

Can you manually operate the glow-plug relay(s) or bridge them to see if the plugs do indeed come on?
If they do then the relays bust or the control side is not getting the volts/signal to fire the relay?

kermit_rr · Feb 21, 2023

DanClarke said:
Can you manually operate the glow-plug relay(s) or bridge them to see if the plugs do indeed come on?
If they do then the relays bust or the control side is not getting the volts/signal to fire the relay?

theres lots of wires, more than i expected to each relay.. i'll have to look after work.. dont know how to send a fire signal to the relay.. i'll see if i can find a wiring diagram that makes sense and not just a logic diagram

DanClarke · Feb 21, 2023

kermit_rr said:
theres lots of wires, more than i expected to each relay.. i'll have to look after work.. dont know how to send a fire signal to the relay.. i'll see if i can find a wiring diagram that makes sense and not just a logic diagram

Did you read this post through for inspiration?
https://www.landyzone.co.uk/land-rover/help-no-power-to-glow-plugs-on-l322.277887/

kermit_rr · Feb 21, 2023

what i can do, shortly, is put my amp clamp over the glow plug loom and see if there is any activity. i will report back

DanClarke · Feb 21, 2023

kermit_rr said:
what i can do, shortly, is put my amp clamp over the glow plug loom and see if there is any activity. i will report back

Well as its a 100A Fuse you ought to see summat!

Saint.V8 · Feb 21, 2023

This is all I have to hand - and this is for the 3.6 - although I assume the logic would be the same....

marjon · Feb 21, 2023

Thought I posted you a dia?

Will look tomorrow .

J

kermit_rr · Feb 21, 2023

DanClarke said:
Well as its a 100A Fuse you ought to see summat!

i think mine is 2x60A

kermit_rr · Feb 21, 2023

Saint.V8 said:
This is all I have to hand - and this is for the 3.6 - although I assume the logic would be the same....

thanks, i found another doc for that engine, but again hopefully the same...

When the ignition switch is turned to position II, the ECM calculates any required heating times and, if heating is required,
energizes the glow plug relays in the BJB. W hen pre heating is required, the ECM also sends a message to the instrument
cluster, on the high speed controller area network (CAN), to request illumination of the glow plug indicator. The glow plug
indicator remains illuminated for the duration of the pre heating phase, or until the ignition switch is turned to the crank
position, whichever occurs first. If required, the ECM keeps the glow plug relays energized during cranking and for the
duration of any post heating phase.

kermit_rr · Feb 21, 2023

ok, the relays have 2 plugs each, one goes to a bank of glow plugs, the other is power, plus 4 other.. signal? wires?
engine is cold, the relays should be coming on and I've confirmed they aren't, none of the 8 are getting any power. they should be used when engine is below 50c so something isn't right. All 3 big fuses are OK, so its a signal issue/bad connection somewhere. I can't imagine both controllers have gone bad at exactly the same time

L322 4.4 tdv8 glowplugs not glowing

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