Independent Renault Forums banner

1 - 20 of 21 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter #1
hi folks
hope somebody can help,i have a w reg scenic 16 16v and have had some problems with a slight missfire ,i removed the plugs and found that one was covered in black soot ,i know its not the coil packs as they are fairly new and has had a new map sensor also a new icv have cleaned tdc sensor but not renewed also has just passed its mot and flew through the emmisions test so what else should i look for in resolving this problem
many thanks
alan
:confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused:
 

·
Premium Member
Joined
·
43,291 Posts
Black spark plugs are a sign the fuel isn't being ignited properly.

Have you actually checked the spark plug is actually getting a spark?:)
 

·
Registered
Joined
·
29 Posts
Discussion Starter #3
hi yes there is a spark could it be possible that there is a fault in the wire that goes to the coil pack, all the other spark plugs are fine
thanks
 
R

·
Guest
Joined
·
0 Posts
Have you done a compression test on the cylinder?
or it could be an injector fault
Last week I had a problem with No3 mifiring found that one of the wires to No3 injector had a kink in it and investigating further found that the wire insulation was damaged and the copper wire inside was broken and all green with corrosion when we stripped the insulation back.

It looks to me that the wire must have been trapped at some point by the aluminium housing that protects the fuel rail.
 

·
Registered
Joined
·
29 Posts
Discussion Starter #7
looking from left to right the third plug is the one i am having problems with ,i have taken fuel rail off and swapped injectors over and still have same problem with no 3 plug . if compression was low on that one pot would it have passed the emissions test at the time of mot on wed/13/2011 as it passed all tests
 
R

·
Guest
Joined
·
0 Posts
looking from left to right the third plug is the one i am having problems with ,
Thats No2 plug as No1 is at the gearbox end Renault don't seem to follow the usual convention.


if compression was low on that one pot would it have passed the emissions test
IMO If the fuel wasn't being burnt correctly for what ever reason it wouldn't have passed the test.

the time of mot on wed/13/2011 as it passed all tests
Is there an extra month now?:)
 

·
Registered
Joined
·
29 Posts
Discussion Starter #10
forgot to mention when i start the car up it seems to hunt but when i blipp the accelerator its seems fine also has a slight missfire at low speed and seems fine when i did 70 on the motorway today
 

·
Registered
Joined
·
29 Posts
Discussion Starter #11
forgot to mention when i start the car up it seems to hunt but when i blipp the accelerator its seems fine also has a slight missfire at low speed and seems fine when i did 70 on the motorway today
also bought some cataclean today to see if that helps
 

·
Premium Member
Joined
·
43,291 Posts
Try interchanging a couple of ignition coils around and see if the fault follows.

If it was a faulty CAT it would affect all cylinders.:)
 

·
Registered
Joined
·
29 Posts
Discussion Starter #13
just a quick update have changed the fuel rail and injectors and no longer get the smell of petrol on start up but still a little chuggy when i start engine as if only firing on 3 cylinders but fine when i rev it up,does not missfire as it use to do when going through the gears has anybody got any more ideas what to look at next:confused::confused::confused::confused::confused::confused::confused::confused::confused::confused:
 

·
Registered
Joined
·
29 Posts
Discussion Starter #17
opps spoke to soon
car runs great with no sign of missfire at all, but when i leave it for a few hours and try to start it up it runs very lumpy untill i rev it and then its fine again
i have cleaned the tdc ,replaced the injector rail and injectors,cleaned spark plugs,even used catclean.coils must be ok as i have no missfire even changed the coolant temp sensor with a new one but still problem is still there anymore helpfull ideas:mad:
 

·
Registered
Joined
·
29 Posts
Discussion Starter #20
just a quick update ,
i bought a second hand coolant temp sensor and about 4 inches of of the wiring loom from local scrapy and cut off my old loom and soldered the wires,replaced my new temp sensor with the second hand one .Now car starts first time with no lumpy tickover or smell of petrol,the big test will be tomorrow when engine is stone cold will let you know how it goes but thanks to all for all the advice:d
 
1 - 20 of 21 Posts
Top