Renault Scenic Misfiring
Vehicle Renault Scenic 03 plate, 1.8 petrol engine, 36000 miles.
Have had intermittant misfiring of plugs, now getting worse, replaced plugs, all 4 coils and appeared OK for a few days, have recently refilled tank.
All plugs OK, have tested coils and again OK, slight signs of condesation at base of 2 coils, damp blown out by air and sprayed with water repellant, engine still sounds and feels as if running on 2 cylinders, very noticable up to 2500 to 3000 revs.
Any suggestions to cure please. Thanks
Know, what you are going through, got the same issue!
On mine it was it a split air intake hose, beware you have to buy it complete with box at about £60. Cured the problem for a few days, but now back again. I was going to replace coils next, but see you have done that with no improvement. I have someone with diagnostic gear who is going to look at it this week, will let you know how we get on. Have you changed air filter...thats a job ! Also try blasting injecter cleaner down air intake manifold, apparently it can take the slightest bit of grit to disturb set up !
Hi Brad ,
Thanks for your reply, here is my update, my misfire was getting slowly worse I had to book it in for a diagnostic test at a Renault dealer (I wont give names at Mo) They did the test and found "Destructive Misfire" eventually after an hour and missing my next appointment they said fault found.
It was described as 2 plugs rusted to hell (they were), all four plugs replaced AND 4 coils and the engine was running smoothly ! BUT I was told that the engine was very lumpy with my coils fitted , this was not heard by myself in garage as they would not originally allow me in workshop, as I was running late I had to accept their diagnosis and repair at £220.
A few days later, I put my coils back on one by one replacing the Sagem/Renault ones, guess what - only one of my coils were faulty, no wonder they would not show my coils fitted, no print out from diagnostics to show only one cylinder misfiring.
Now considering how to get money back !!!!!!!!!
I intend to invest in a handportable diagnostic meter about £30 - £60 on ebay, sorry but I no longer trust dealers.
Note:- All four plugs were replaced 6 months ago, appears heavy rain may have got into drainage channel behind engine, overflowed and dripped in to plug recess, hence water shorting out, also it was noted that when I took out the original Renault coils when fault developed , there were no rubber rings around coil to prevent damp getting in, also suggest putting some grase around ring on coil .
I had a similar problem but with one cylinder. I removed all the coils and found one of them wet at the bottom. It was the offside one ( 1 or 4 ? )
On closer inspection I found the rubber boot at the bottom had come unstuck and filled with water.I resealed it and swapped with another coil. The water had got into the coil via a rotten washer pipe juction that sits above it connected to the bonnet. I changed the washer pipe and hey presto ......no leaks and firing on all four.