HELP - Got a missfire!

[after_shock]

Perfect timing as always as taking it to get mapped on Thursday but pulled the car out the garage today, took it to give it a clean about 2 miles taking it very easy didnt exceed 1800rpm, washed it dried it and on the way back about 20seconds into the drive started miss firing under accelaration.

Ive looked at all the plug leads nothing seems to have melted, no warning lights have came on just misses under accelaration, where do I start with the problem finding? Need it running by Thursday to take to get it mapped!

Not sure if any coincidence but a message appeared when started it up this morning 'service engine oil' never seen it before, is this just a maintenance message or something else?

Thanks in advance for any help!!

[007 VXR]

after_shock said:

Perfect timing as always as taking it to get mapped on Thursday but pulled the car out the garage today, took it to give it a clean about 2 miles taking it very easy didnt exceed 1800rpm, washed it dried it and on the way back about 20seconds into the drive started miss firing under accelaration.

Ive looked at all the plug leads nothing seems to have melted, no warning lights have came on just misses under accelaration, where do I start with the problem finding? Need it running by Thursday to take to get it mapped!

Not sure if any coincidence but a message appeared when started it up this morning 'service engine oil' never seen it before, is this just a maintenance message or something else?

Thanks in advance for any help!!

cant help you with this ... but iam have been getting the "service engine oil" lighting up as well ???



just spoke to andy at the fish ...dont worry about the oil sign ..just reset it .... good luck with the other problem

Edited by 007 VXR on Friday 20th November 16:04

[stigmundfreud]

service engine oil is just a counter you can ignore you can reset via console. Your misfire... wondering if as you have said you've checked plugs etc it might be ltft mucking up fuel.

Cannot remember teh fues number or lable but look out for I think the BCM fues. Remove this (await confirmation from others to verify) and then leave it for a few minutes turn the ignition on, it will give you a warning. Do this a few times (no need to start) then put the fues back in, turn on and run. This will reset LTFT and eliminate that from the equation

the other option is to disconnect battery for long enough to ensure no the setting is wiped.

Edited by stigmundfreud on Friday 20th November 16:09

[ringram]

I doubt its fuel trims.
Did you clean under the bonnet? If so you might have just wet stuff. It should dry out. Check lead connections and see if its ok when she is all dry in about 6 months time

[stigmundfreud]

doubt it too but if it was fine then went for a spin, came back and it started to mess about it could be especially as he has cam swap with no retune at present

[after_shock]

Didnt clean under the bonnet, never do will hose pipes etc!

It doesnt sound like its got a miss just sat idling only when accelarating if that helps at all, also seems to do it worse in some gears as opposed to others.

Im going to have a look at the car again now after leaving for a few hours on the off chance it was something getting wet (lets hope!)

[After_Shock]

Still doing it annoyingly so not water which didnt think it would be!

Didnt seem to do it at first when driving but then came in again, its worse the higher the gear am in, for example 30mph in 2nd can hardly notice it in 3rd gets more pronounced but in 4th is terrible.

Accidentally went over 2k rpm to get out of a junction and it felt as if the problem went all together, didnt want to re-try thos revs with the cam etc being put in.

Shall I try the fuse thing to re-set the fuel trims?

[stigmundfreud]

try it but I hold no responsiblity! it could be any number of things from st fuel to a plug going off to a faulty lead. Shame you dont have at least a scanner to see the log data.

its the perils of changing the internals without mapping accordingly

[After_Shock]

If its likely to screw the car up I wont risk taking the fuse out!

The fuels the same as whats been in for a few weeks so can rule that out not put any fresh in it.

Ive pushed all the leads on to make sure they are secure, not checked the plugs but thats something going to have to do by the looks of it.

Is their not a fault code reading thing built into the car that can access via the menu system on start up? Im sure remember reading about it.

[neiljohnson]

after_shock said:

Perfect timing as always as taking it to get mapped on Thursday but pulled the car out the garage today, took it to give it a clean about 2 miles taking it very easy didnt exceed 1800rpm, washed it dried it and on the way back about 20seconds into the drive started miss firing under accelaration.

Ive looked at all the plug leads nothing seems to have melted, no warning lights have came on just misses under accelaration, where do I start with the problem finding? Need it running by Thursday to take to get it mapped!

Not sure if any coincidence but a message appeared when started it up this morning 'service engine oil' never seen it before, is this just a maintenance message or something else?

Thanks in advance for any help!!

Sounds to me like the plugs could be fouling up with fuel, try taking one out and looking if its heavily fouled then thats your answer hth

[granada203028]

If it is OK idling and low load/gentle driving but starts at high load then probably a HT lead or plug fault. At high load, cylinder pressures are higher and that means the spark needs more volts, so more likely for it to go elsewhere if lead etc is dodgy.

[After_Shock]

If the plugs are fouling up with fuel how do I solve that problem??

Will have a look at the plugs over the weekend, what tools do I need off the top of anyones head to get them out? House is a bomb site at the minute due to a new central heating system being fitted so finding anything is a nightmare, if start tonight will have them in time for tomorrow night lol

[crisisjez]

If all you did was clean the car then its either unrelated and coincidental or its something you did get wet.

Have you tried running the car with the traction control switched off, could be a faulty sensor.

[stigmundfreud]

you'll need a plug socket, an extender bar, a decent ratchet and some time. Just take one at the front out to check.

The fuse wont do anything but reset learnt fuel trims. From memory without reading up you said its at low load/idle not under load?

disconnect battery for 20 minutes and try that instead of removing the plug. It could but I doubt even be as simple as a terminal on the battery being lose, could be absolutely anything (had that issue before).

The problem is if you are getting the plugs out, the back bank are a complete swine to get at i resorted to using sarahs small hands to get them out once I had undone them.

At the present as it could be absolutely anything there should be no hardship in doing the trim reset

this is a rough guide http://sikls1.v8owners.com.au/index28.html to pcm reset

[after_shock]

crisisjez said:

If all you did was clean the car then its either unrelated and coincidental or its something you did get wet.

Have you tried running the car with the traction control switched off, could be a faulty sensor.

Not tried it but will give it a go tomorrow with the TC off. With regards to the cleaning the bonnet was down and nothing looks damp/wet or soggy under the bonnet, probably just coincidental as taking the car to get mapped, always happens when need to go somewhere

[after_shock]

stigmundfreud said:

you'll need a plug socket, an extender bar, a decent ratchet and some time. Just take one at the front out to check.

The fuse wont do anything but reset learnt fuel trims. From memory without reading up you said its at low load/idle not under load?

disconnect battery for 20 minutes and try that instead of removing the plug. It could but I doubt even be as simple as a terminal on the battery being lose, could be absolutely anything (had that issue before).

The problem is if you are getting the plugs out, the back bank are a complete swine to get at i resorted to using sarahs small hands to get them out once I had undone them.

At the present as it could be absolutely anything there should be no hardship in doing the trim reset

this is a rough guide http://sikls1.v8owners.com.au/index28 to pcm reset

It idles fine but the more the load the worse the mis gets, if that could relate to the same thing?

See what you mean about the back plugs they look like an utter sod to get at! Should it not have a warning on the dash to say somethings up??

Thanks for all the help so far

[monkfish1]

Mmmm, cracked plug insulator id say. Or a lead mabe. Given that you have just had headers

[after_shock]

monkfish1 said:

Mmmm, cracked plug insulator id say. Or a lead mabe. Given that you have just had headers

Cheers for the reply appreciate it, annoying thing is it drove the 40miles home perfectly fine and also the couple of miles this morning this same then just started, if that rules anything out that may have been damaged in the process of fitting the headers.

Felt right around the leads and none have melted through or anything.

[monkfish1]

after_shock said:

monkfish1 said:

Mmmm, cracked plug insulator id say. Or a lead mabe. Given that you have just had headers

Cheers for the reply appreciate it, annoying thing is it drove the 40miles home perfectly fine and also the couple of miles this morning this same then just started, if that rules anything out that may have been damaged in the process of fitting the headers.

Felt right around the leads and none have melted through or anything.

Cracked insulator may not cause a problem straight away. Just when the damp gets in.

[after_shock]

Where are the insulators located?