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[John Lewis]

Hi all

I've still got my misfire - no EML showing either - so far here's the list of fixes I've been through:

New back box (baffles went, witches hair everywhere)
Manifold gasket replacement (Courtesy of Elite Pete)
DIS pack (Courtesy of Elite Pete)
HT leads (Courtesy of Elite Pete)
Spark plugs (Genuine Vauxhall/GM, but they gave me single electrode, don't know if this could be related to misfire)
Disconnected the MAF (but the misfire is still there when disconnected when revving engine).

If you lightly touch the accelerator, there's no misfire at all. As soon as you put any pressure on it, even a tiny bit more, the car starts spluttering, then jolts into action at about 75% of its healthy power - which is great for SWMBO's bad neck! Also the car idles at around 500rpm, trying to stall -but the auto choke kicks in and keeps it alive, this happens every 2-3 seconds when stationary, and is bloody annoying to put it mildly.

I cleaned the plug to the MAF and put it back on, seemed a little better but got worse again after a few minutes. Part of the rubber around the plug is missing on the cable, but only a bit.

I'm losing coolant too but this is the HBV, which I am booking in soon.

Its driving me NUTS! 

Is there anything I may have overlooked apart from the MAF? I'm not convinced this will solve the problem completely. 

 

[cem_devecioglu]

have you checked cambelt timing ?

[John Lewis]

No mate, how easy would it be for a part-mechanophobe like me to attempt? Should I pass it on to someone? Gonna change the MAF first as I have a donor car coming which has a known good one.

Ta

J

[cem_devecioglu]

if the cambelt is 1-2 teeth out it can do that..

also missfires cause unburnt fuel which is not good for cats..

you can get some help from close members or mobile mechanics from oof imo..

[cem_devecioglu]

a more easy approach could be compression test also..

if the compressions are low this will give more clue about the probabilities..

http://www.youtube.com/watch?v=XcmIPm8M3Xw&feature=related

[OmegaGav]

Hi all

I've still got my misfire - no EML showing either - so far here's the list of fixes I've been through:

New back box (baffles went, witches hair everywhere)
Manifold gasket replacement (Courtesy of Elite Pete)
DIS pack (Courtesy of Elite Pete)
HT leads (Courtesy of Elite Pete)
Spark plugs (Genuine Vauxhall/GM, but they gave me single electrode, don't know if this could be related to misfire)
Disconnected the MAF (but the misfire is still there when disconnected when revving engine).

If you lightly touch the accelerator, there's no misfire at all. As soon as you put any pressure on it, even a tiny bit more, the car starts spluttering, then jolts into action at about 75% of its healthy power - which is great for SWMBO's bad neck! Also the car idles at around 500rpm, trying to stall -but the auto choke kicks in and keeps it alive, this happens every 2-3 seconds when stationary, and is bloody annoying to put it mildly.

I cleaned the plug to the MAF and put it back on, seemed a little better but got worse again after a few minutes. Part of the rubber around the plug is missing on the cable, but only a bit.

I'm losing coolant too but this is the HBV, which I am booking in soon.

Its driving me NUTS! 

Is there anything I may have overlooked apart from the MAF? I'm not convinced this will solve the problem completely. 

 

Hi, I know you changed the leads and plugs but could be worth rechecking, you seem to be having exactly the same problem as i did recently, check if one of the plugs is a different colour to the others ?
Have a look here :

http://www.omegaowners.com/forum/YaBB.pl?num=1272097222

 

[John Lewis]

Hiya Gav and cheers everyone for the input thus far.

I found the same problem as you, a split HT lead insulator (the last pig one to get to back one on the dispack side) that must have been arcing to the engine, however we swapped that out and the problem still remains.

Slightly, but only slightly different problem to yours - this lead swap *did* improve things re: performance but the misfire is still there, whatever the engine temp. And idle is wavering all the time. Shudder on revving through 1000-2000revs.

The temperature sensor is also working fine.

I might still try the EGR valve thing though, it befits the problem, especially rough idling/trying to stall.

Just to be clear - I unbolt it, then bolt it back on with a bit of metal blocking it out, and reconnect before firing up the car, yes?  And a sign of a failed one is no change in performance?

Bloody thing, lol.

[cem_devecioglu]

Hiya Gav and cheers everyone for the input thus far.

I found the same problem as you, a split HT lead insulator (the last pig one to get to back one on the dispack side) that must have been arcing to the engine, however we swapped that out and the problem still remains.

Slightly, but only slightly different problem to yours - this lead swap *did* improve things re: performance but the misfire is still there, whatever the engine temp. And idle is wavering all the time. Shudder on revving through 1000-2000revs.

The temperature sensor is also working fine.

I might still try the EGR valve thing though, it befits the problem, especially rough idling/trying to stall.

Just to be clear - I unbolt it, then bolt it back on with a bit of metal blocking it out, and reconnect before firing up the car, yes?  And a sign of a failed one is no change in performance?

Bloody thing, lol.

yep..block it with a metal sheet.. and dont break it while you torque (I did ) .. and connect the socket.. 

and if you can try a compression test imo you will have more info about your engine condition..

and if you want a complete checklist here is: 

- Ignition
• spark plugs – Swap with good cylinder
o Inspect for built up, oil or smell of gas
• faulty ignition coils-– Swap with good cylinder
• faulty camshaft position sensor
• Look for loose or dirty connections
• Get a sparkplug tester and look for spark
• Use Ohm meter to test continuity

Fuel
• dirty injectors- Inspect and swap with good cylinder
• Verify it is spraying- Note computer may shut of gas to misfiring cylinder to protect the catalytic converter
• Low fuel pressure, faulty pressure regulator
• Fuel supply faulty (filter ad pump)
• Use Multimeter to test continuity and voltage

Compression
• Do a compression Test
• Loss of compression could be
o worn out piston rings (look for blue smoke)
o leaking head gasket look for (white smoke)
o Sticky, Stuck, or improperly seated valves


Vacuum
• Leaking air intake system

[OmegaGav]

Hiya Gav and cheers everyone for the input thus far.

I found the same problem as you, a split HT lead insulator (the last pig one to get to back one on the dispack side) that must have been arcing to the engine, however we swapped that out and the problem still remains.

Slightly, but only slightly different problem to yours - this lead swap *did* improve things re: performance but the misfire is still there, whatever the engine temp. And idle is wavering all the time. Shudder on revving through 1000-2000revs.

The temperature sensor is also working fine.

I might still try the EGR valve thing though, it befits the problem, especially rough idling/trying to stall.

Just to be clear - I unbolt it, then bolt it back on with a bit of metal blocking it out, and reconnect before firing up the car, yes?  And a sign of a failed one is no change in performance?

Bloody thing, lol.

Thats it i used tin foil folded several times !

Mine was a split plug lead also on No6 pot the last one to get out 
Could still be worth re checking the plug leads are connected securley to the dis pack and plugs, can be easy to knock about while doing things round the back of the engine 

Are they in the right order  :-/

[John Lewis]

Interesting stuff there, pleeeenty of info to be going on there, cheers!!

OK I just looked outside in the dusk and I can see what looks like carbon deposit thats ran down the side of the EGR over time, could this be a sign that its blocked, or is this a normal thing?

I'm gonna get it off tomorrow and try it out when its light again, then report back...

I farkkin love this place. 


EDIT: I presume theyre in the right order, Elite Pete did the work thank gawd 

[cem_devecioglu]

Interesting stuff there, pleeeenty of info to be going on there, cheers!!

OK I just looked outside in the dusk and I can see what looks like carbon deposit thats ran down the side of the EGR over time, could this be a sign that its blocked, or is this a normal thing?

I'm gonna get it off tomorrow and try it out when its light again, then report back...

I farkkin love this place. 


EDIT: I presume theyre in the right order, Elite Pete did the work thank gawd 

its normal, exhaust gases flowing inside..

[eliteomegaman]

Hia John
I've joined the exclusive 'misfire/stuttering' club & have lost all me hair with the problem 
Have my own thread x 2 going but thought i'd gatecrash you 
Mine could be exhaust manifold gasket or that my cats are knackered as everything else is fine (renewed everything but the kitchen sink!!) EXCEPT my wallet which is now empty 
Could your problem be the same??

[John Lewis]

Haha nice.

I've already done the manifold gasket, ok well Elite Pete did (and gained Tourettes Syndrome in the process no doubt!).

I cleaned out and also blocked off the EGR to test earlier on, but it wasn't even stuck open or closed, its cleaner now though, so I'm hoping its just the MAF. As soon as some bloody client finally pays up and stops ruining my life I'll be able to find out!

My mates a mechanic and he's just having his cats done on his Vectra to get it thru the MOT - having just done his MAF which fixed his car, which was uncannily similar in its problem to mine. He reckons MAF is the most likely cause thus far as well.

Ah well, back to chasing payments...cheers guys :-/

[cem_devecioglu]

Haha nice.

I've already done the manifold gasket, ok well Elite Pete did (and gained Tourettes Syndrome in the process no doubt!).

I cleaned out and also blocked off the EGR to test earlier on, but it wasn't even stuck open or closed, its cleaner now though, so I'm hoping its just the MAF. As soon as some bloody client finally pays up and stops ruining my life I'll be able to find out!

My mates a mechanic and he's just having his cats done on his Vectra to get it thru the MOT - having just done his MAF which fixed his car, which was uncannily similar in its problem to mine. He reckons MAF is the most likely cause thus far as well.

Ah well, back to chasing payments...cheers guys :-/

personally I wouldnt be so sure ..trial error is ok but without real purchase..

[eliteomegaman]

Hia John
Like your good self i'm at my tether to find out what the f*ck is causing this mysterious misfire/stuttering 
When Captain Zok's son had a look at my poorly motor back at easter he found no fault codes showing but No. 6 plug was cracked & swimming in oil   
One of the new plugs fitted on monday along with new set of ht leads & a compression test (which showed no problems) was a different colour (not sure which plug) & the car has only travelled a mile or so, its been suggested that could be rocker cover gaskets.  If its the rocker cover then could this be the cause of the misfire/stuttering   :-?
So far i've had 3 people with 4 different theories -
1. Exhaust manifold gasket
2. Knackered cats
3. Maf sensor
4. Leaking rocker covers
I'll take a poke in the dark & based on the different coloured plug i'd say no. 3   :-/
Anyone want to participate in this exciting guessing game