could a weak battery cause misfire + irratic idle etc. ?

[franx]

I've done the leads and coilpack, seemed to benefit from this but the misfire/stuttering has come back. The battery is very old , had it checked and the measure-device said "replace, bad battery"

The fault readout when having it plugged in for diagnosis last week only mentioned a fault; "bad earth"

Could this be down to my weak battery (which is also way down in the spare-wheel comp with way longer wire than usual) ?

 

[ben_init]

check your plugs, make sure they are nice and clean - i had bad idle/ irratic for a while, until i noticed 2 of my plugs had oil round them - changed the rocker gasket n it fixed it, but i would suggest replacing the battery anyway

 

[franx]

^ thanks , thing is that some 5000 miles ago i threw in some of the proper NGK plugs so these should last another 50K. The "bad earth" faultcode points me in the direction of the battery (because it's a bad one). Just bought a proper nice one and am about to install it.

Will post up as this COULD be a second misfire/battery related case ! I have read/searched a LOT of threads and there was one other case that had the battery being the cause of it's misfire. Will be down to a weak spark then i guess

 

[franx]

The new battery has just been installed and it has gotten a lot better ! No more misfire, it does still struggle a bit coming down in revs down to idle. It is a LOT better than before though :approve:

Tommorow i will clean+check all the earths and see if i can get the last little judders out

 

[Jonny1*2]

why would the battery make a difference mate? Main power drain is from starting no? Might be a wiring issue somewhere which is failing to supply current at the correct voltage. French wiring = fail

 

[franx]

^^ correct in theory ! Yeah also when looking at the (French) wiring it makes me cry, for f**k's sake it looks like s**t.

But I read about someone else here with a bad battery that had the same probs and this fixed it ?? It should'nt really matter though , strange eh ?

I think the battery being in the boot , with the long live( wire) going there , means that the battery has got to be in correct working order. Anyway, the faultcode was bad earth so i'll go on checking them

 

[Jonny1*2]

You could be right then mate. It starts ok I assume though, so cranking amps must be fine. ECU earth might be a shout.

 

[franx]

^^ you are speaking the same words as the man i have spoken to this evening ! He said battery should'nt matter all that much and better i check the ECU earths

Thanks , good feedback here

 

[franx]

well this is strange. the new battery brought me one evening of joy as the prob seemed to be far better/almost dissapeared.
It's back. :dead:

So... a new + fresh powersource cured it (seemingly) for a couple of hours ? What's strange is that when booting it it seems NOT to misfire. Also hesitates to get back to idle and this in a juddering way.. Sticky injector ?

aaaaaarrrrgghh !!! thrown 300+ at it and no cure yet

 

[franx]

It was a faulty injector...