Member Since: 10 Mar 2021
Location: Nicosia
Posts: 79
Cold starting issues after gearbox Recon (!?)
Hello to all,
So my D3 started having problems on the initial start-up of the day. First start-up seems fine but as soon as you let the key go the car switches off. Second start-up the car idles rough for 10-15 seconds and then its ok. Does this only when cold (in the morning and after I finish work). When it's warm it starts and idles just fine.
Temp has not dropped dramatically here (it's about 12-14 degrees C.)
I don’t think this is relevant -at least it shouldn’t- but the car just had a gearbox and TC overhaul and it started doing this.
No faults, no lights, no bings or bongs.
After reading up on this and concluding to some usual things to check I took some readings as below to help clear things up.
This is just before starting the car cold (ignition on)
These are readings just after starting the car up when cold.
The only thing left to check are the glow plugs I guess but then again it is kind of a risky job. I was also advised to bleed the fuel system in case there's any air trapped inside?
Any suggestions?
P.S.: yesterday and today morning when starting up the car I let it crank a bit more (after it actually started). It did not switch off but still idled rough for about 10-15 seconds
Thanks in advanceDiscovery 3, TDV6, HSE, 2006
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Last edited by AndreasG on 13th Dec 2022 1:41 pm. Edited 1 time in total
8th Dec 2022 9:30 am
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 79
Anyone?Discovery 3, TDV6, HSE, 2006
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9th Dec 2022 2:32 pm
disco chris
Member Since: 25 Apr 2022
Location: London
Posts: 251
Not too sure where you should look next, but I doubt it will be glow plugs causing your issue if temps are still above 10 degrees C so I wouldn't worry too much about them.
I wouldn't continue to crank the car once it's already running though
Hopefully someone will be along soon who can help more than this, but I suppose I would look at injector values from your IID compared to others (lots of threads on here). Also potentially whether the fuel flow is sufficient, when did you last change the fuel filter?
9th Dec 2022 3:52 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 79
I’ve been hearing people’s issues with the glow plugs and indeed everyonenis talking about minus degrees so kind of having doubts about them being the issue myself.
I change fuel filter every 10k miles. I’m about 2k miles from the next changeDiscovery 3, TDV6, HSE, 2006
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9th Dec 2022 4:57 pm
disco chris
Member Since: 25 Apr 2022
Location: London
Posts: 251
That should be plenty frequent enough if the fuel is good quality. Could be worth a change though, as a potential quick and cheap fix.
Other guesses would be HPFP / LPFP
9th Dec 2022 7:27 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 79
I don’t know if the fuel filter needs to be removed (or should) in order to change the gearbox, as mentioned above. If thats the case maybe it was misplaced?
Would’t the LPFP/HPFP throw up any codes?Discovery 3, TDV6, HSE, 2006
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9th Dec 2022 7:39 pm
Flatlander
Member Since: 20 Jul 2015
Location: Here
Posts: 575
Try turning the ignition on for 30-40 seconds, then off, then start. If that helps, it's likely getting air in somewhere. Also check the fuel filter 'plumbing' if you have the earlier one mounted on the chassis leg adjacent to the right front wheelarch, it's possible the flow & return pipes have been mixed up.
9th Dec 2022 7:56 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8144
When first starting, turn the ignition on and listen for the low pressure pump to stop running, takes about 2 minutes then turn ignition off a back on and start engine and see if it still does it, if it doesn’t you have a low pressure fuel supply.
As above, slow typing It can when others can't,
It will when others won't,
It goes where others don't.
9th Dec 2022 8:08 pm
Mastertech
Member Since: 13 Apr 2014
Location: North East
Posts: 128
Stick your head under and check around the front of the fuel tank for a fuel leak too.
9th Dec 2022 8:28 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 79
Thank you all for your replies.
I’ll try this tomorrow and lreport backDiscovery 3, TDV6, HSE, 2006
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9th Dec 2022 8:42 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 79
Latest update:
Tried leaving the ignition on for about 2 minutes then started the car; same thing! (video in link below). Temp at the time was 18 degrees C. which I think rules out the glow plugs).
*I did not turn the key back and then back on again, I just started the car straight away from ignition- don't know if that makes any difference.
I also filled up with petrol today and I had TERRIBLE consumption. I'm down to 18MPG from my usual average of 21-22 (same roads same commute) and usually people state that they get much better consumption after doing their box!
I also spoke with the garage that carried out the gearbox overhaul and they said they didn't touch the fuel filter.
Is there any way to check the LPFP from the GAP Tool lke any readings?
Member Since: 04 Oct 2018
Location: Kent
Posts: 596
You say you filled up with petrol did you mean diesel?
11th Dec 2022 9:19 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 79
Yes sorry I meant Diesel. Direct translation confusion.Discovery 3, TDV6, HSE, 2006
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12th Dec 2022 7:43 am
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 79
So after a very long discussion with a co-worker (who is a mechanic albeit on a different brand) and after I explained all the symptoms, he concluded that its most likely to be a crank sensor misreading.
I crucially forgot to mention that while I had the car in for the gearbox I asked the garage to change the rear engine seal, which I now come to realize has a ring of some sort so the crankshaft sensor gets its values from! The mechanic there sounded quite confident that he could do it and that it was no hassle.
(I am no expert mechanic myself, I can do the light work and more of the theory rather than the practice)
So now I ask the more experienced people out there, could this be causing all my problems?
The car now feels a bit sluggish and there seems to be a flat spot while accelerating after around 2,500rpm.
Could they have moved or incorrectly placed anything while working there?
Is there a way I can check or are there any readings to get through the GAP tool?
My mechanic had a short drive in it yesterday and he reassured me the car is definitely not the same as before but will not get the chance to look at it properly until Friday and I have a long journey planned for the weekend.
Any help would be appreciated PLEASE as I am now actually losing sleep over this (I know I worry too much) but I'd rather be pro active rather than damage something else
Thanks in advanceDiscovery 3, TDV6, HSE, 2006
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13th Dec 2022 1:39 pm
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
It sounds reasonable that some issue exists with the crankshaft position sensor since it was removed to change the rear seal. It could be the sensor, a connector not fully seated, or the sensor not fully seated. The sensor is highly sensitive to its placement as it works by detecting the trigger wheel position by monitoring changes in a magnetic field.
From the shop manual:
“ The CKP sensor is located at the rear of the engine block on the left hand side. The sensor tip is aligned with a magnetic trigger which is attached to the crankshaft. The reluctor is a press fit on the end of the crankshaft. The trigger wheel must be carefully aligned to the crankshaft to ensure correct timing. The sensor produces a square wave signal, the frequency of which is proportional to engine speed.
The ECM monitors the CKP sensor signal and can detect engine over-speed. The ECM counteracts engine over-speed by gradually fading out speed synchronised functions. The CKP is a Hall effect sensor. The sensor measures the magnetic field variation induced by the magnetised trigger wheel.
The trigger wheel has two missing teeth representing 6o of crankshaft rotation. The two missing teeth provide a reference point for the angular position of the crankshaft.
When the space with the two missing teeth pass the sensor tip, a gap in the signal is produced which the ECM uses to determine the crankshaft position. The air gap between the sensor tip and the ring is important to ensure correct signals are output to the ECM. The recommended air gap between the CKP and the trigger wheel is 0.4 mm- 1.5 mm.
The ECM uses the signal from the CKP sensor for the following functions:
\0- Synchronisation.
-\0 Determine fuel injection timing.
\0 -Enable the fuel pump relay circuit (after the priming period).
-\0 Produce an engine speed signal which is broadcast on the CAN bus for use by other systems.”2008 LR3 HSE, 4.4L V8
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