Misfiring And Stinking Of Petrol

[johnhenry 20]

Morning all

ive recently replaced the blue connector temp sensor (solved the weird revving problem), re-tracked the AFM (for good practice), had a new advance vacuum

Whilst these have improved the car initially, its presented a new set of issues, surprise surprise

 

When starting it up from cold it fires really quickly (ive also checked the injectors all reading ok) but it sounds like one cylinder isnt firing on start up, raise the revs for about 3 seconds its and its fine when it comes back down.

also the car hums of petrol when starting up and jus generally seems to be all the time.

 

It sounds like a fuel air mixture issue causing the car to overfuel, but ive done the AFM which controls the mix right? so im slightly confused :S

and any ideas on the missing cylinder? is there a way of finding which one it is? any ideas as to why its missing?

i used to be running wynns value lift additive in it which has been removed now as ive changed the oil in the last 500 miles. i dont know if this makes a difference to this particular issue :S

 

Thankyou all...again

[NeilGTi85 5]

I would suggest a compression check and a good check of the exhaust manifold, as they crack quite alot making the cabin stink of fuel

[Weser 30]

The overfuelling could be down to the fact you have done the AFM. Have you put it on a gas analyser to see what the readings are. It could be you moved the dial or it is more acurate now the tracks have been done? Worth seeing what the CO content reading is to make sure.

 

The miss fire might be down to the overfuelling then when you rev it it burns the excess fuel and is fine again.

 

Sounds to me like it is overfuelling on idle. I would put it on a analyser and go from there.

[johnhenry 20]

The overfuelling could be down to the fact you have done the AFM. Have you put it on a gas analyser to see what the readings are. It could be you moved the dial or it is more acurate now the tracks have been done? Worth seeing what the CO content reading is to make sure.

 

The miss fire might be down to the overfuelling then when you rev it it burns the excess fuel and is fine again.

 

Sounds to me like it is overfuelling on idle. I would put it on a analyser and go from there.

 

yeh man, i need to get some readings done on it, gona take it to an emmisions tester this afternoon hopefully, £20 down the drain but worth it

 

and ive replaced the Manifold when i got the car dude so doubt its already cracked

[Rich_p 23]

Check the TPS sensor is working correctly (it tells you in the Haynes manual how to do this) , I had one go on mine and it stank of fuel constantly and was very jittery, check the vac advance pipe is on too.

[johnhenry 20]

Check the TPS sensor is working correctly (it tells you in the Haynes manual how to do this) , I had one go on mine and it stank of fuel constantly and was very jittery, check the vac advance pipe is on too.

 

Cheers dude ill do it when im home!

what does TPS stand for sorry :/ haha

[Carbs4me 45]

Cheers dude ill do it when im home!

what does TPS stand for sorry :/ haha

 

 

Throttle position sensor easy to find as its a little black box on your thottle.. it should move slightly aswell when unbolted to change the position.

[DamirGTI 344]

Next morning , prepare yourself before starting it from cold , in order to catch affected cylinder ... so you'll need to be quick and do this before it stops misfiring (if it does stop when it reaches operating temp ?)

 

Start the engine , pop up the bonnet and pull spark plug leads one by one (wear gloves) just a touch upwards from the spark plug and observe/listen the engine - if it's fine you'll notice an drop in rmp. and slight engine shaking , re-connect the plug lead and proceed further until (or of) you find cylinder which wouldn't show not a single change in rmp. , the one which doesn't affect the engine when you pull the lead from the spark plug - if you spot this , you've got problem on this cylinder ..

 

Do the same with the injectors (remove connector securing clips first before starting up the engine) , by disconnecting/connecting injector connectors with the engine running ..

 

Ditto , id suggest compression check as well .

 

Damir