Misfires all the way along the rev range...

Changed the spark plugs and it's still doing it.

I just want a course of action on what to do.

I'm thinking of sticking some carb cleaner in the throttle body.

The checking temp sensor.

Then eventually lambda sensor

But Id like some other cheaper options before I spend £50-£60 on a new lambda.

Suggestions?

Misfires all the way along the rev range...

Changed the spark plugs and it's still doing it.

I just want a course of action on what to do.

I'm thinking of sticking some carb cleaner in the throttle body.

The checking temp sensor.

Then eventually lambda sensor

But Id like some other cheaper options before I spend £50-£60 on a new lambda.

Suggestions?

Maybe your distributor or HT leads are fucked? Try unplugging the leads one by one till you find out which pot isn't firing. You could try a new lead on that cylinder... Obviously turn the engine off before messing with the HT leads.

Could do...

Oh and it's a 1.0L petrol engine

I'd pull the distributor cap off and have a look what sort of state the cap and rotor arm are in. Considering doing a full ignition service, I do when buying a new (to me) car. Plugs (you've done), leads, rotor arm and distributor cap.

I'd check your timing as well.

I'd pull the distributor cap off and have a look what sort of state the cap and rotor arm are in. Considering doing a full ignition service, I do when buying a new (to me) car. Plugs (you've done), leads, rotor arm and distributor cap.

I'd check your timing as well.

Thought timing was controlled by ECU...

Took it out today, doesn't miss fire from cold (turns out I hadn't shoved the HT leads back on properly) but still does when then engine's warm...

If you have a missfire you car will run alright when the engine is cold and when its cold outside, it will be really bad on wet days. I just had a missfire and fixed it, I changed the leads and plugs but it was still there. Someone told me to check my dizzie cap and rotar arm and when I removed my dizzie cap, my rotar arm was in pieces and the shaft it sits on was fucked, you can tell by grabbing it and seeing if there is any play in it. Got a new distributer and its been running sweet since. I work for VW and had loads of their mechanics look at it and not one of them checked the dizzie cap. My rotar arm was they bad they honestly couldn't work out how it had been running.

^^ Why do you think I suggested to have a look at the dizzy cap and rotor arm?

^^ Why do you think I suggested to have a look at the dizzy cap and rotor arm?

Dizzy cap and rotor arm is a bit borked. Not borked, just worn, probably hasn't been changed in the 99K miles the car's done.

Ill probably replace the cheapy bits (this) and if it don't go away, get rid and get myself a newer W or X reg oloP...

Replaced rotor arm and dizzy cap. Still wank.

Next up is different fuel then temp sensor and if still fucks about then Ill ditch it in favour of a newer one...

Replaced rotor arm and dizzy cap. Still wank.

Next up is different fuel then temp sensor and if still fucks about then Ill ditch it in favour of a newer one...

Have you checked all the HT leads aren't fucked?

They're fine

Replaced rotor arm and dizzy cap. Still wank.

Next up is different fuel then temp sensor and if still fucks about then Ill ditch it in favour of a newer one...

I still say your timing is out. Have you even tried a timing gun on it?

Replaced rotor arm and dizzy cap. Still wank.

Next up is different fuel then temp sensor and if still fucks about then Ill ditch it in favour of a newer one...

I still say your timing is out. Have you even tried a timing gun on it?

Ain't got a timing gun to hand.

My mate however works for VW so I'm hooking up to a Vag-com type thingy (I say type thingy as it's the proper VW thing, not vag-com) not this weekend comming, the one after.

I've ruled out fuel and it's only doing it from one the engine warms up. As I said before, I thought timing was ECU controlled, anyone clarify?

I don't know about Mk4s but I'm guessing you still have a distributor, doubt they are solid state?

I believe you can advance or retard the ignition by twisting the distributor.

if your saying you thought the timing was controlled by the ECU are you sure you should be checking and changing bits under the bonnet yourself mate? basically the timing is set by the position of the pulleys that the timing belts goes round, it synchronises the crankshaft and cam shaft/s so the pistons, valves, etc all work together

I'm talking about ignition timing... Not cam timing. And some cars the ignition timing is controlled completely by the ECU.

try the coil, worked with mine!

Every misfire I've ever had has been cured with a good clean of the TB or carb, other than that could it be the MK4's blue temp sensor?, I'm more experienced with the MK2 engines than MK4.

May be best to run it through VAG software thats how they found a problem with my MK4.

Every misfire I've ever had has been cured with a good clean of the TB or carb, other than that could it be the MK4's blue temp sensor?, I'm more experienced with the MK2 engines than MK4.

May be best to run it through VAG software thats how they found a problem with my MK4.

Not the carburettor, not the HT leads, not the spark plugs, not the dizzy cap, not the rotor arm. Just changed the temperature sensor which DID show up on a VAG machine (an old one where you enter values) and it's STILL misfiring. Unplugged the lambda, re ran VAG test, 0 errors O.o

My mate who works at VW thinks it could either be an over fuel in the engine or maybe the lambda sensor. MOTs coming up in August, so Ill just do that, it fails on emissions, Ill try the lambda sensor. Really is an odd fault now.

I'm assuming the blue temperature sensor is the one that measures coolant temperature and coolant pisses out all over your gearbox when you unplug it...

Edited 5 July, 200719 yr by crazyman50000

That's the one.

If you've pulled the lambda sensor out and it still misfires, then I don't see the problem with the lambda sensor? The way your car is at the moment you probably haven't got much to lose by loosening off the dizzy and twisting it either way (remember to tipex its location) to see if it improves.

seeing as the lambda only comes into play once certain engine criteria are met, eg: temp!

i would say it would be lambda, you can easily check this on the dealers 5051/5052 i would have presumed, u can on later models, if not a voltmeter will surfice.... your vw mate should now about engine readiness and basic fuel trim! *tut tut*

if its the 6n 8v or 16v 95 on. MPI/SPi models, the ignition timing is controled by the ECU. Have you changed the throttle body? These things have a motor built in, and also a position sensor. The position sensor often wears out. This data is fed back to the ECU. If the Sensor gets a bit of dirt, or the contacts wear, cause bad data to the ECU..which in the end throws up faults.

Also there is a Temp/pressure sensor on the intake manifold. May me also a duff injector..VAGCOM is the the way to track faults. but somthime you get lucky.

hope ity helps.

ohh.. and check that your plugs are tightly down too!!!

Andy

Changed the HT leads now.

That's the plugs, rotor arm, ht leads and dizzy cap all replaced.

:(

Compression tested. Results as follows :

Cyl 1 - 125PSI

Cyl 2 - 125PSI

Cyl 3 - 125PSI

Cyl 4 - 100PSI

Seems cyl 4 is likely to be the cause. Anyone got a solution?

Think I've fixed it!

A £3.99 bottle of valve cleaner later and it's slowly making a difference...

Did you ever solve this?