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Old 14th April 2019, 02:22 PM
DailyMike DailyMike is offline
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Default Changed ONE coil (Cylinder 5)...BUT...

...since I changed the Cylinder 5 coil pack yesterday, it has eliminated the multiple cylinder misfires across BOTH banks!

Logically, I believe that they would be independently wired, but the frequent (several times daily), multiple cylinder misfire codes for the last few days have DISKAPPEARED and the car's running sweet as a nut!

So...are the coil packs somehow linked?

DailyMike.
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Current modes of transport:
2002 A8 4.2 (40v) Quattro Sport, 18" QS wheels; Prins LPG, Silver; Black leather; newly-refurbished wheels in Anthracite...pics to follow soon!
2000 P38 Range Rover Vogue 4.6 V8 LPG, Epsom Green, fully-rebuilt engine (Top-hat liners, new camshaft for better mid-range torque); New S/S sports exhaust...SOUNDS BRILLIANT!
2006 LWB Ford Transit 2.4 Diesel, Luton Van; Tail-lift; leaking translucent roof
2014 Mondraker TrakkerR; 29-er, 30-speed gear train; rise'n'fall saddle; Mountain bike...NOT a cart-horse!
"JONDOR" a 116' long, 17"6" beam Humber Barge, Built 1950, ex oil tanker, fully refurbished Gardner 6LXC engine for propulsion (one day); requires new marine gearbox; 2-cylinder Petter Diesel engine & 3-cylinder diesel auxilliary engines with 12/24v and 230/415v gensets
"JONDOR" is a slow-burn project, being converted to provide suitable accommodation for wheelchair users and their carer/family for short respite breaks. Currently moored on River Humber at Old Beverley Shipyard

Previous vehicles:
Far too many to list individually, but includes 2005 A8 D3 3.0TDI Quattro Sport; 2007 A6 3.0TDI Avant; 2005 A4 2.0 Avant; 2007 A3 2.0TDI; 7-off Citroens, Many Fords, Austin 1100 (my first car), Lotus 7, Rover SD1 3500; SAAB 9000i, SAAB 9000 turbo; BMW 530; another P38 Range Rover (the crap one with BMW 2500 diesel engine...wouldn't tow the skin off a rice-pudding! )
Daren't even mention the traumatic Morris Marina and Ital's....even an Austin Princess. Brain is now hurting somewhat, so giving up for now...
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Old 14th April 2019, 08:06 PM
ainarssems ainarssems is offline
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Quote:
Originally Posted by DailyMike View Post
...since I changed the Cylinder 5 coil pack yesterday, it has eliminated the multiple cylinder misfires across BOTH banks!

Logically, I believe that they would be independently wired, but the frequent (several times daily), multiple cylinder misfire codes for the last few days have DISKAPPEARED and the car's running sweet as a nut!

So...are the coil packs somehow linked?

DailyMike.
I am not 100% sure about this but I have definitely witnessed the same behaviour. I think what happens is after certain number on misfires ECU cuts fuel for the misfiring cylinder to stop unburned fuel going in exhaust and damaging cat, that means only air passes through that cylinder, lambda probe reads it as too lean mixture and increases fuel for remaining cylinders, if it gets too rich it will cause misfires on other cylinders. Now again I am not sure but I think it would be fair to assume that ECU is smart enough not to do this and just switch off lambda monitoring when it cuts fuel for 1 cylinder in which case it runs only on MAF readings and if the MAF is a bit out or if injectors are either worn letting more fuel through or partially clogged letting less fuel through then mixture will be wrong and may cause misfires.
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Old 14th April 2019, 08:26 PM
DailyMike DailyMike is offline
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Originally Posted by ainarssems View Post
I am not 100% sure about this but I have definitely witnessed the same behaviour. I think what happens is after certain number on misfires ECU cuts fuel for the misfiring cylinder to stop unburned fuel going in exhaust and damaging cat, that means only air passes through that cylinder, lambda probe reads it as too lean mixture and increases fuel for remaining cylinders, if it gets too rich it will cause misfires on other cylinders. Now again I am not sure but I think it would be fair to assume that ECU is smart enough not to do this and just switch off lambda monitoring when it cuts fuel for 1 cylinder in which case it runs only on MAF readings and if the MAF is a bit out or if injectors are either worn letting more fuel through or partially clogged letting less fuel through then mixture will be wrong and may cause misfires.

Interesting...thanks for the input!

I should likely have mentioned that the car is run solely on LPG once it's warmed up to the required temp...about 60C I believe. At that point, I believe the Prinz LPG ECU would be in control?

Mike.
PS: Car STILL running sweet as a nut!
I'll be doing about 400 miles tomorrow with my grandkids, so that'll be a good test...
__________________
Current modes of transport:
2002 A8 4.2 (40v) Quattro Sport, 18" QS wheels; Prins LPG, Silver; Black leather; newly-refurbished wheels in Anthracite...pics to follow soon!
2000 P38 Range Rover Vogue 4.6 V8 LPG, Epsom Green, fully-rebuilt engine (Top-hat liners, new camshaft for better mid-range torque); New S/S sports exhaust...SOUNDS BRILLIANT!
2006 LWB Ford Transit 2.4 Diesel, Luton Van; Tail-lift; leaking translucent roof
2014 Mondraker TrakkerR; 29-er, 30-speed gear train; rise'n'fall saddle; Mountain bike...NOT a cart-horse!
"JONDOR" a 116' long, 17"6" beam Humber Barge, Built 1950, ex oil tanker, fully refurbished Gardner 6LXC engine for propulsion (one day); requires new marine gearbox; 2-cylinder Petter Diesel engine & 3-cylinder diesel auxilliary engines with 12/24v and 230/415v gensets
"JONDOR" is a slow-burn project, being converted to provide suitable accommodation for wheelchair users and their carer/family for short respite breaks. Currently moored on River Humber at Old Beverley Shipyard

Previous vehicles:
Far too many to list individually, but includes 2005 A8 D3 3.0TDI Quattro Sport; 2007 A6 3.0TDI Avant; 2005 A4 2.0 Avant; 2007 A3 2.0TDI; 7-off Citroens, Many Fords, Austin 1100 (my first car), Lotus 7, Rover SD1 3500; SAAB 9000i, SAAB 9000 turbo; BMW 530; another P38 Range Rover (the crap one with BMW 2500 diesel engine...wouldn't tow the skin off a rice-pudding! )
Daren't even mention the traumatic Morris Marina and Ital's....even an Austin Princess. Brain is now hurting somewhat, so giving up for now...
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  #4  
Old 14th April 2019, 08:42 PM
ainarssems ainarssems is offline
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LPG ECU normally is not standalone unit but a piggy-back from the main ECU, main ECU calls all the shots if it does not tell injector to open LPG ECU will not open it.
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  #5  
Old 15th April 2019, 06:28 AM
DailyMike DailyMike is offline
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Originally Posted by ainarssems View Post
LPG ECU normally is not standalone unit but a piggy-back from the main ECU, main ECU calls all the shots if it does not tell injector to open LPG ECU will not open it.
Good to know and sooooo reassuring that there's such a wealth of knowledge on the forum!

100 miles into today's trip and running beautifully!

DailyMike.
__________________
Current modes of transport:
2002 A8 4.2 (40v) Quattro Sport, 18" QS wheels; Prins LPG, Silver; Black leather; newly-refurbished wheels in Anthracite...pics to follow soon!
2000 P38 Range Rover Vogue 4.6 V8 LPG, Epsom Green, fully-rebuilt engine (Top-hat liners, new camshaft for better mid-range torque); New S/S sports exhaust...SOUNDS BRILLIANT!
2006 LWB Ford Transit 2.4 Diesel, Luton Van; Tail-lift; leaking translucent roof
2014 Mondraker TrakkerR; 29-er, 30-speed gear train; rise'n'fall saddle; Mountain bike...NOT a cart-horse!
"JONDOR" a 116' long, 17"6" beam Humber Barge, Built 1950, ex oil tanker, fully refurbished Gardner 6LXC engine for propulsion (one day); requires new marine gearbox; 2-cylinder Petter Diesel engine & 3-cylinder diesel auxilliary engines with 12/24v and 230/415v gensets
"JONDOR" is a slow-burn project, being converted to provide suitable accommodation for wheelchair users and their carer/family for short respite breaks. Currently moored on River Humber at Old Beverley Shipyard

Previous vehicles:
Far too many to list individually, but includes 2005 A8 D3 3.0TDI Quattro Sport; 2007 A6 3.0TDI Avant; 2005 A4 2.0 Avant; 2007 A3 2.0TDI; 7-off Citroens, Many Fords, Austin 1100 (my first car), Lotus 7, Rover SD1 3500; SAAB 9000i, SAAB 9000 turbo; BMW 530; another P38 Range Rover (the crap one with BMW 2500 diesel engine...wouldn't tow the skin off a rice-pudding! )
Daren't even mention the traumatic Morris Marina and Ital's....even an Austin Princess. Brain is now hurting somewhat, so giving up for now...
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  #6  
Old 16th April 2019, 10:06 AM
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27litres 27litres is offline
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Quote:
Originally Posted by ainarssems View Post
LPG ECU normally is not standalone unit but a piggy-back from the main ECU, main ECU calls all the shots if it does not tell injector to open LPG ECU will not open it.
I would second this.
My understanding of LPG ECUs is that they take the injector pulse signal from the car ECU and use that as its own injection trigger. The difference is that the LPG ECU will deliver a proportionately longer injection pulse as the engine requires more LPG than petrol. And of course it will be responsible for interrupting the signal to the petrol injector.
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Marty


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2002 Audi S8 - Project
Replacement head coming arrived thanks to MJ
Silver with Black interior. All features as the '01, with the 'S' mode auto shifter. Dodgey rear tint (need to find a way to get rid of that).
Family:
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- has a louder more obnoxious exhaust than the S8, sounds great! Love this thing - Q7 was double the price, and certainly not double the car!

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  #7  
Old 16th April 2019, 07:00 PM
DailyMike DailyMike is offline
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Quote:
Originally Posted by 27litres View Post
I would second this.
My understanding of LPG ECUs is that they take the injector pulse signal from the car ECU and use that as its own injection trigger. The difference is that the LPG ECU will deliver a proportionately longer injection pulse as the engine requires more LPG than petrol. And of course it will be responsible for interrupting the signal to the petrol injector.
Cheers, Marty!

I'm just totally chuffed that the problems have now been sorted so easily!

DailyMike
__________________
Current modes of transport:
2002 A8 4.2 (40v) Quattro Sport, 18" QS wheels; Prins LPG, Silver; Black leather; newly-refurbished wheels in Anthracite...pics to follow soon!
2000 P38 Range Rover Vogue 4.6 V8 LPG, Epsom Green, fully-rebuilt engine (Top-hat liners, new camshaft for better mid-range torque); New S/S sports exhaust...SOUNDS BRILLIANT!
2006 LWB Ford Transit 2.4 Diesel, Luton Van; Tail-lift; leaking translucent roof
2014 Mondraker TrakkerR; 29-er, 30-speed gear train; rise'n'fall saddle; Mountain bike...NOT a cart-horse!
"JONDOR" a 116' long, 17"6" beam Humber Barge, Built 1950, ex oil tanker, fully refurbished Gardner 6LXC engine for propulsion (one day); requires new marine gearbox; 2-cylinder Petter Diesel engine & 3-cylinder diesel auxilliary engines with 12/24v and 230/415v gensets
"JONDOR" is a slow-burn project, being converted to provide suitable accommodation for wheelchair users and their carer/family for short respite breaks. Currently moored on River Humber at Old Beverley Shipyard

Previous vehicles:
Far too many to list individually, but includes 2005 A8 D3 3.0TDI Quattro Sport; 2007 A6 3.0TDI Avant; 2005 A4 2.0 Avant; 2007 A3 2.0TDI; 7-off Citroens, Many Fords, Austin 1100 (my first car), Lotus 7, Rover SD1 3500; SAAB 9000i, SAAB 9000 turbo; BMW 530; another P38 Range Rover (the crap one with BMW 2500 diesel engine...wouldn't tow the skin off a rice-pudding! )
Daren't even mention the traumatic Morris Marina and Ital's....even an Austin Princess. Brain is now hurting somewhat, so giving up for now...
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