Missing and popping!!

[marc1330]

After driving away from the southwest meet the old cup started misfiring when running and backfiring at idle. It seems worse up to 3K Rpm then gets better. Also on idle it starts to pop and backfire. There does not seem to be any lights coming on,on the dash. So whats the best place to start replacing parts first? Leads and plugs then coilpack if no better or other way round. Or maybe a trip for some diagnostics?

 

[Mark One]

My money is on the coilpack

 

[Inferno]

Mine pops and crackles when I first start it up, but stops doing it after the ECU has changed to the proper map after 90 seconds or so.

 

[marc1330]

Coilpack sounds likely after doing a few searches plus the engine management light has come on. Are they expensive?
Thinking of getting RAC out to see if their diagnostics will pick it up

 

[Jon.L]

they all pop at the start dont they? sounds great on the over run with then k-tec stealth!

 

[fil_b]

had this twice on mine

1st was the spark plugs

2nd i took the inlet off, took all the HT leads off the plug and reassembled and seems ok now (touch wood)

 

[marc1330]

Got the old RAC out coilpack gone. The chappy didnt have a spare except for VAG cars as he said they eat coilpacks, so hes coming round my house tomorrow after i finish work to fit one just parts cost. Top service

 

[marc1330]

Re: Missing and popping!! and some

Right then the RAC came out changed coilpack and that did nothing. So had a look a the plugs and they are w***ed right out. The car has done 47k and im amazed the thing ran atall.
So we changed the plugs and all was well but after the RAC man had gone I took the car out for a spin it runs really well but the engine management light will not go out. Do i have to get the ecu reset or is there more probs. Would be surprised as the car is now running really well

 

[MikeB]

disconnect the battery for 10 minutes and the light might go out

 

[Rich]

Normally needs 2 or 3 clean starts and the light will go out.

 

[Bash]

run a quick test by pushing in the trip computer then turn on.

 

[marc1330]

Cheers chaps will give all a go will let you know how i get on

 

[marc1330]

Tried all of the ideas but no joy i hope that running it home from work the other day hasn't fooked the cat. I take it thats its going to be a renault job. Took it out for a little blast and it was running well

 

[Bash]

Lamba sensor? you would hear a huge difference if you cat was gone.

 

[Aluco]

if your cat was gone i think it would "tinkle" ?

 

[marc1330]

Getting the ecu reset sat hope that does it. Would be surprised if lamda has gone as the running prob was the plugs, unless the missing, backfiring etc has knackered the lambda?

 

[Bash]

missing and backfire is normally a lamba sensor problem. maybe ur cat is buggered and building up too much back pressure. try jacking ur car up and hitting the cat with a hammer (or such) if it rattles then ur cats gone. May also me a small hole so try blocking ur exhaust breifly and see if engine changes note.

 

[marc1330]

Decat time!!

 

[Bash]

I have a spare cat left over form my old car I think its in good condition, I've never used it and havent seen it in like a year but £25 if u want to pick it up.

 

[marc1330]

Cheers boss but i think It may of sorted itself. Been using the car today lots of little journeys and the light has gone out, hopefully it stays out now.

 

[m4rkie23]

had this on the 172.
turned out to be the spark plugs (or atleast 1 of them - it was shot to pieces)

the extra fuel that isnt burnt goes into the cat and this was making the exhaust monitor light show. caused mis-firing and terrible idling.

tried the coil pack and a new one made no difference. would of changed the leads but the plugs did the job perfectly (set of ngk platinums approx £8 each from apd), and the leads are in excess of 100quid and take a few days for renault to get hold of (according to the stealer.....tut tut)

 

[stu-172]

had this on the 172.
turned out to be the spark plugs (or atleast 1 of them - it was shot to pieces)

the extra fuel that isnt burnt goes into the cat and this was making the exhaust monitor light show. caused mis-firing and terrible idling.

tried the coil pack and a new one made no difference. would of changed the leads but the plugs did the job perfectly (set of ngk platinums approx £8 each from apd), and the leads are in excess of 100quid and take a few days for renault to get hold of (according to the stealer.....tut tut)

Leads are 45ish + vat! I think said stealer was robbing you blind!

 

[m4rkie23]

yeah thought that would be the case. didnt have time to get online at the time, but i will keep that in mind as it would only take half hour to change them!

where did you see them at that price then?