Member Since: 16 Sep 2019
Location: Swindon
Posts: 41
Long crank time
A quick troubleshooting question for the hive mind:
What would cause a long crank time and rough idle when cold? By 'rough idle' i mean the whole car will shake. Once warm and driven, it starts instantly and no rough idle.
If the MAFs are unplugged, I still have a long crank time when cold but no rough idle.
5th Oct 2023 8:50 am
nigethecat
Member Since: 11 Sep 2016
Location: Marnoch
Posts: 4244
Glow plugs...I want to see the sweets before I get into your windowless van... I'm not stupid!
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5th Oct 2023 9:47 am
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73081
Or injectors……
5th Oct 2023 9:53 am
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73081
Or both.
5th Oct 2023 9:53 am
JafaDiscoIV
Member Since: 16 Sep 2019
Location: Swindon
Posts: 41
Re: Long crank time
nigethecat wrote:
Glow plugs...
I have no codes for that. If it were glowplugs, would you still expect the rough idle to be there regardless of whether the MAF was unplugged?
5th Oct 2023 9:54 am
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73081
Injector balance numbers?
5th Oct 2023 9:57 am
JafaDiscoIV
Member Since: 16 Sep 2019
Location: Swindon
Posts: 41
DSL wrote:
Or injectors……
I've replaced the full set of injectors but no change. 8PSI from the LPFP after the filter, HPFP still produces over 1700Bar on hard acceleration so I'd be surprised if that were the issue. MAF readings also match my other discoveries.
5th Oct 2023 9:57 am
JafaDiscoIV
Member Since: 16 Sep 2019
Location: Swindon
Posts: 41
DSL wrote:
Injector balance numbers?
Click image to enlarge
These are the correction values at just over 2000rpm
5th Oct 2023 10:00 am
JafaDiscoIV
Member Since: 16 Sep 2019
Location: Swindon
Posts: 41
DSL wrote:
Injector balance numbers?
Click image to enlarge
and this is at idle.
5th Oct 2023 10:04 am
hgrimmett
Member Since: 11 Oct 2009
Location: Bledlow
Posts: 901
Did you ever get anywhere with your diagnostics on this? I have the same issue. Glow plugs pull 45a on both sides so they appear to work. The car had 2 new injectors when the engine was rebuilt and the other 4 were bench tested and within specs in the last 3 months, so I'm happy that it's not either of those issues but my symptoms match yours exactly but I've not tried unplugging the MAF. No codes...-------------------------------------------------------------------
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26th Jan 2024 10:36 pm
JafaDiscoIV
Member Since: 16 Sep 2019
Location: Swindon
Posts: 41
hgrimmett wrote:
Did you ever get anywhere with your diagnostics on this? I have the same issue. Glow plugs pull 45a on both sides so they appear to work. The car had 2 new injectors when the engine was rebuilt and the other 4 were bench tested and within specs in the last 3 months, so I'm happy that it's not either of those issues but my symptoms match yours exactly but I've not tried unplugging the MAF. No codes...
I know the struggle. Hopefully I have the answer you need.
I fully drained the fuel tank and replaced with good quality shell diesel and all my issues went away.
Let me know how you get on.
26th Jan 2024 10:54 pm
hgrimmett
Member Since: 11 Oct 2009
Location: Bledlow
Posts: 901
Thanks! Good for you, glad to hear you solved the issue. Was your problem only a very short term issue then? A dodgy tank of fuel? My problem has been there since the engine was rebuilt, I know I should go back to the garage but it's too far away, it's been 3 months but it runs otherwise fine and starts ok when hot or if I preheat with the FBH. I'll try as you suggest! When you say 'drain' did you just run it low or mechanically empty it? Maybe I should change the fuel filter too?-------------------------------------------------------------------
D4 '15 (64) Se Tech Indus Silver
Tesla Model Y LR (22)
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Tesla Model 3 LR (70) (gone)
Porsche Boxster '96 2.5 5spd project (P)
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26th Jan 2024 11:04 pm
JafaDiscoIV
Member Since: 16 Sep 2019
Location: Swindon
Posts: 41
If you've used multiple tanks of fuel, I imagine this won't help you. I stopped driving mine during diagnostics so the one tank lasted a while. Do you get any random kicks while driving when warm like the power turns off for 1/8th of a second?
Either way I'd try unplugging the MAFs before anything else. Easiest solutions first.
Mine is doing the same. If I preheat with the fbh is grand. If I try to warm the plugs multiple time before cranking it’s ok,generally. If I forget and it’s been cold the car cranks for more that a few sec and I get rough idling for a bit. As soon as I move it forward a few feet it all settles down. So I put this down to glowplugs and the long crank flooding the engine.
Happy to hear other thoughts from the raft of experts here
28th Jan 2024 8:35 am
hgrimmett
Member Since: 11 Oct 2009
Location: Bledlow
Posts: 901
JafaDiscoIV wrote:
If you've used multiple tanks of fuel, I imagine this won't help you. I stopped driving mine during diagnostics so the one tank lasted a while. Do you get any random kicks while driving when warm like the power turns off for 1/8th of a second?
Either way I'd try unplugging the MAFs before anything else. Easiest solutions first.
No, i don't get anything like that. I did get something like surging when cruising on part throttle at 30 but that seems to have settled down. I'll try replacing the fuel filter and dticking some premium diesel through...-------------------------------------------------------------------
D4 '15 (64) Se Tech Indus Silver
Tesla Model Y LR (22)
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Tesla Model 3 LR (70) (gone)
Porsche Boxster '96 2.5 5spd project (P)
Mini R52 S (54)
BMW 330e eDrive MSport '16 (gone)
D3 '07 (56) XS TDV6 Buckingham Blue (gone)
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