mercman1969
Active Member
- Joined
- May 18, 2005
- Messages
- 300
Mis-Fire - the Fault Codes
- Thread starter mercman1969
- Start date
gina2201
MB Enthusiast
mercman1969
Active Member
- Joined
- May 18, 2005
- Messages
- 300
interesting read
Swapped back to my old MAF today as have to wait for report from bosch before can get refund or replacement
this evening...car ran like new for 40 miles again
fault is obviously intermitant.......difficult to work out what componant would fail intermittantly
MAF?
Lamda Sensor?
anybody any ideas
Swapped back to my old MAF today as have to wait for report from bosch before can get refund or replacement
this evening...car ran like new for 40 miles again
fault is obviously intermitant.......difficult to work out what componant would fail intermittantly
MAF?
Lamda Sensor?
anybody any ideas
gina2201
MB Enthusiast
It could still be the MAF, I had times of hope when I thought the problem was solved but alas no, once I changed the MAF there was never any further probs!
I'm no expert so can't really comment on what the problem you have is but it is such a relief to get it sorted!
I'm no expert so can't really comment on what the problem you have is but it is such a relief to get it sorted!
So, a quick summary:
Plugs, coil packs and leads are new(ish)
Fault appears (and goes away) with 2 Bosch MAFs
Original set of codes listed included adaption limit reached etc codes as well as misfire codes
Codes show misfire across multiple sets of cylinders (more than one coil pack).
You will now stray into "try this" territory - sort of like the coil pack and MAF expenditure already made....that didn't fix it.
I would suggest you go to a clued-up indie (while LPG is switched out) and:
Get the codes all read (some you posted first have multiple sub-codes that need Star/DAS to read properly).
Get the codes cleared.
Get the car read while running/misfiring - the live data SHOULD pinpoint why/where the ability to create and control proper mixture is going wrong.
You will find lots of suspicion around the LPG interfaces - I would certainly want that fully disabled and ideally removed if I was diagnosing this one!
(if you want to have a free fiddle over Christmas, I would suggest checking over the whole intake area for air leaks (from MAF to cylinder head) - you might have a joint somewhere that leaks when you go over a bump - unmetered air coming and going could lead to all your symptoms. Equally, a badly fitted air filter letting in road dirt could ruin 2 MAFs failrly quickly...).
Plugs, coil packs and leads are new(ish)
Fault appears (and goes away) with 2 Bosch MAFs
Original set of codes listed included adaption limit reached etc codes as well as misfire codes
Codes show misfire across multiple sets of cylinders (more than one coil pack).
You will now stray into "try this" territory - sort of like the coil pack and MAF expenditure already made....that didn't fix it.
I would suggest you go to a clued-up indie (while LPG is switched out) and:
Get the codes all read (some you posted first have multiple sub-codes that need Star/DAS to read properly).
Get the codes cleared.
Get the car read while running/misfiring - the live data SHOULD pinpoint why/where the ability to create and control proper mixture is going wrong.
You will find lots of suspicion around the LPG interfaces - I would certainly want that fully disabled and ideally removed if I was diagnosing this one!
(if you want to have a free fiddle over Christmas, I would suggest checking over the whole intake area for air leaks (from MAF to cylinder head) - you might have a joint somewhere that leaks when you go over a bump - unmetered air coming and going could lead to all your symptoms. Equally, a badly fitted air filter letting in road dirt could ruin 2 MAFs failrly quickly...).
Last edited:
Also, I assume that when you changed the ignition components, you did choose the correct plugs and gap them correctly for your particular LPG conversion?
(the conversion will specify a plug type and, usually, a smaller gap than standard - this is because LPG is very hard to ignite versus petrol and so, if the gap is left standard, a MUCH higher HT voltage will be required for a spark which WILL accelerate plug, HT lead and coil wear....)
Are your plugs still OK? (8,000 miles at too wide a gap would result in burning and pitting).
(the conversion will specify a plug type and, usually, a smaller gap than standard - this is because LPG is very hard to ignite versus petrol and so, if the gap is left standard, a MUCH higher HT voltage will be required for a spark which WILL accelerate plug, HT lead and coil wear....)
Are your plugs still OK? (8,000 miles at too wide a gap would result in burning and pitting).
- Joined
- Feb 8, 2007
- Messages
- 20,694
- Location
- Portsmouth, Hampshire.
- Car
- E55K SL500 E250X2 Smart44 Brabus Track car E450Cabriolet X350 Pick up
Live data is the key here.
You need to observe it while the miss is apparant.
You need to observe it while the miss is apparant.
sasha091
Member
i got my MAF REPLACED (AFTER READING WHAT HAPPENED WITH YOUR CAR)
& THANKS A MILLION MISFIRES NO MORE.
REGARDS
DR.SHAH
& THANKS A MILLION MISFIRES NO MORE.
REGARDS
DR.SHAH
