Major missfire on 02 plate 172

[merlin7]

Hi just had engine out and fitted a replacement as lower crank pully broke in half causing cam belt to jump so replaced engine ,belts ,dephaser pully,all the normal stuff while eng was out,all fitted up started car found fault on number 4 injector,so changed injector and started it up car was ticking over ok drove off ramp out of garage to test drive and felt a slight missfire,went to fuel up and car started missfiring more and also backfiring and popping through exhaust.No eng man light was on car seemed to not want to rev,Eng was timed up as it should be so can anyone give any clues where to look next,Changed sensors over from old engine to new engine no change,seem to have a good spark at the plugs

 

[Austin-182]

My advice would be to get it to a specialist who knows what they are doing.

Where do you live?

 

[merlin7]

west yorks

 

[theburns1]

Sounds like timing, you sure it was all timed up correctly

 

[merlin7]

yes timing was 100%correct it was ticking over smooth untill i drove it,now tickover is very lumpy to the extent it nearly stalls

 

[theburns1]

Could be low on compression, who did you buy the engine off?

 

[bloke]

air leak?

 

[merlin7]

Ren parts Doncaster eng was tested and running ok before purchase allegadly.Also new gaskets fitted so air leak may be unlikely everything was checked and double checked before starting also used all genuine Renault parts.

 

[stb182]

mine was missing and farting, back firing popping through exhaust. was told common fault coil, even tho it seamed to have good spark at plugs, changed that still same whent back to basics and changed spark plug leads sorted, running fine now

 

[merlin7]

did you just change the leads stb or plugs too,i changed plus 12 months ago

 

[theburns1]

What leads you got, how close are they, they could be arking

 

[stb182]

car had service about 200 miles ago new plugs were fitted then, so just tryed new leads, very surprised that cured it.. £20

 

[merlin7]

ive still got the genuine Renault leads on

 

[theburns1]

I'm into my old fords and its pretty common that the leads on them use to ark due to touching, lead being old ect and cause misfire.