V6 Misfire

[Ben82]

Hello all

Yesterday when I was driving I noticed the check engine light was on and the service light was on too. And I thought "that's odd, it didn't beep and come up with a message on the display".
Shortly after noticing that, the car started to vibrate quite a bit, and idle was rough, got the car home - as I was in the middle of nowhere and about 15 mins from home, but it was getting worse the closer I got to home.

After getting it home, I tried starting the car a couple of times, and the check engine light and service light remained on.... But it seemed like it was running ok.
Switched off went to get the lexia out, and basically had codes 0356 (and due to that 0306, and 0300).

Thought I would try monitoring it to see if it was a faulty coil, so added monitoring to a couple of coil timings, and a few other things, that I thought might help.

Started the car, the timing if I recall was around 2.5xx compared to around 2.1xx for the other coil that I was monitoring, at this time the car started going a bit mental... Anti-pollution fault, engine management fault (I think). the Check Engine light started flashing. So I switched off.

Went inside, sent a message to my local mechanic, to see when he could take a look. I also started to look online for how much it might cost, and whether it's worth getting parts abroad, as they are generally quite a bit more expensive here, and whether I could do it myself.

Given that the codes point to coil 6, I discovered this means the back left cylinder, so requires taking the inlet manifold off. I thought that if it was the front ones I could probably do a swap to see if the misfire moved, and probably do the job myself.

The mechanic hasn't replied so far - I do know he's had health issues over the past few years, so does make me wonder if he's on a break again - or has retired entirely.

I think either way I should probably look at ordering the parts and probably replacing all 3 in one go, rather than waiting for the other two to go too.

Is there anything else I should replace whilst I'm (or the mechanic is) "back there"? I've added a "air distributor seal" to my basket just in case the one that is there isn't reusable. maybe spark plugs? but for me I'm not sure I want to replace too much, just in case I introduce other issues

This does seem to be a pretty good guide for doing the process http://docplayer.net/57144792-How-to-re ... 10bhp.html my only worry with doing it myself is exposing the engine to the elements - even if I use a rag/rags or something to cover the air intake I'm probably going to be a klutz and still have something find its way in there.

As usual, any advice greatly appreciated.

Thanks

Ben

[xantia_v6]

It seems that you have some idea of what you are doing, so I would say that it would be worth doing it yourself, just be careful to note or photograph any cables or hoses that need to be undone, and make sure that nothing is trapped in the wrong place when refitting the manifold.

Unless the spark plugs have been recently done, I would replace them also, to save another job later.

While you have the covers and manifold off, inspect carefully for oil leaks around the camshaft covers, as these are common on ES9 engines, and can cause serious problems (like your misfire), or even an engine fire.

[Ben82]

Hi,

Thanks for the reply. Spark Plugs should have been done when I had the 120,000km service (think around 118k), about 6 years ago now. Car has done just shy of 176,000 now. So seems like they are probably worth changing, then begs the question, should I get all 6 plugs changed?

Good shout on the camshaft covers, I did come across this video last night as well:


Did make me feel like that might not be a job for me to do, especially since the gaskets don't seem to be replaceable and need to use loctite or so instead.

I guess if the worst comes to the worst with that and it isn't a big leak, I guess Ican get the coils sorted and drive the car to one of the garages about 10 minutes away to sort out.

[DHallworth]

I've done the rears on our 406 Coupe with the same engine. Getting the manifold off is really easy, once it's off, there's one bolt that holds the coils in place and they just pull straight up.

When I did ours, Genuine PSA coils were about £30 GBP. I read a lot online and came to the conclusion that on the ES9J4S engine where each cylinder has an individual coil they are prone to failing so I decided to replace all 3 on the back bank in one go therefore saving the bother of removing/refitting the manifold again.

From memory, all 3 were changed and it was back together in 45 mins. On the 406 Coupe you have to take the strut brace off, you don't need to do this on the C5 so that should save you a couple of minutes

David.

[Ben82]

Hi David,

That's good to hear, though I think you're probably far better at working on a car than me

I ordered Delphi coils in the end at about £30 a pop, and some bosch spark plugs... not sure if they need the gap adjusting on them. They were "0 242 229 708", and I am confused whether they are pre-gapped for the V6 or not.

It seems like Cylinder 6 is visible without taking off the inlet manifold (can't get the coil out though). But allowed me to do a visual inspection of the hole, and it looks like there isn't any signs of oil leaking into the hole:


One other question, would starting the engine before doing the work (to verify the misfire) do any more damage? The IT-Tech-Bod in me says I should verify the issue still exists before trying to fix it (conditions have changed - engine cooled etc, so it might not show the same issue). But the "Don't want to make things cost more money" side of me, feels like I should fix it first and prevent any damage to the cats etc.

Thanks

Ben

[xantia_v6]

You won't do any damage by running it briefly, but I would limit it to a minute or two. Damage to the cats would come from them overheating due to raw fuel burning there rather than in the engine.

[Ben82]

Parts finally arrived today. Not entirely impressed with autodoc... took ages to deliver and the spark plug tool I ordered is too big - I guess my fault for thinking their search with the reg-nr would only give compatible parts/tools - doesn't help that 21mm is 13/16ths of an inch, and given that the site only said "13/16, 21,0", I didn't particularly take heed that it might not work.

I did find a 16mm long bit in my toolkit that actually says "SP" on it... but it had a rubber grommet in it that didn't fit round the insulator, took that out and looks like it should work ok - EDIT: just realised this is to "pickup" the spark plug, I don't think it was seated in the socket properly, so have reinserted it and tested it and it's fine.

Hopefully will get a chance to give it a go after work, tad nervous though

[Ben82]

Never straight-forward with my issues (or seems that way anyway).

Was going through nice and slowly, got the airbox out, the piping off (carefully - as they seem like they could be rather brittle from what I've seen - a job for another time I guess).

Got the MAF sensor off. And started on the inlet manifold bolts, all but one would budge. I'm pretty sure they were overtightened by the indy that did the major service a few years back (cambelt change etc).

The bolt felt tighter than the others, and was about as rusty as the others. I tried loads of things and I think I started to make it worse, I practically gave up, thinking I might need to get the local mechanic to get it out.
I did also look online at what sockets could be used for that kind of thing - grip-tite, irwin etc, but couldn't really find anything in my usual array of stored around here that might have that kind of thing.
However, I did notice that most of these had more of an odd flower type shape to them, and I was thinking that I saw something similar in my box of tools, in the form of an E12 socket. Not exactly the same, but it didn't stop me trying. Poped it over one of the loose bolts to ensure I could tighten and untighten the bolt - and it was working.

So thought I'd try it on the nut, only problem was I couldn't find my 3/8ths ratchet (later to be found in the box with the spark plugs and coils ordered - great memory I have there for where I put things ). But I was determined to get it loose (it was getting dark too so I was running out of light), using some probably rather ill advised bits - a wrench and one of the angle extenders.
I knew I was onto something when the E12 socket was stuck tightly on the bolt head, so pressed on, and sure enough it came loose, a huge sigh of relief.

So tomorrow's job will be to do the rest and get a set of new bolts from Citroen - my sister is over in a hire car so handy that she will be able to take me there

[Ben82]

Dealer had to order in the bolts So they won't get them until tomorrow. I might try replacing the coils anyway today and using the old bolts for now just to ensure it fixes the issue (but not driving the car until I get the proper bolts.

[Ben82]

Right, all done.

Had a sigh of disappointment when I started the engine and it was still running poorly and the check engine light was flashing. Checked the codes and the exact same faults were reported, so I thought I'd clear them and try again. It started a little strangely at first, and then kicked in alright, idle seemed smooth, and the check engine light went out completely, and lexia no longer logged a fault!

Took it for a drive and everything seems to be running ok, did all sorts of driving to make sure - town, out on the road driving normally.. flooring it through 1st and 2nd. So seems to be running ok.

One thing I did notice as I was monitoring the coil charge times again.

#6 was fluctuating a fair bit, as per this chart - though the rest were consistent.



Not sure if this is something that would have killed the previous coil? and whether it needs looking at, it sounds like this is probably well within margin of error, but I am one for trying to make sure everything is in order

Also glad that I got a proper torque wrench that covered the spark plug spec today as well, some of the threads got a bit difficult by hand after a while, and I probably would have used that as a guide whether they were in properly or not. At least the torque wrench gave me the piece of mind that those would be correct.

Glad I bought the seal as well... the previous one was well and truly crushed and had some oil around it - as did the intake on the engine, but it seems like this is fairly normal, as some gets caught in the air "recycling" stuff for the engine.