P1336 misfire and hiccups

[Stanleysteamer]

HI
Thanks for reading this.
Started down the road, car seemed to hiccup a bit then further on got much worse, like it was missing.
Found the above code , only.
Which seems to relate to plug or coil pack.
I have read elsewhere that there may be wires rubbing through insulation, (Peugeot forum but I think same motor), and being in French I am a bit surprised they mentioned a "coil". (Bobine) I thought modern cars had "coil packs"? Have to confess have never worked on any other modern car since the days of distributors, all others are either old or diesel).
Anyway the guy found insulation rubbed through, that a lot of garages hadn't found and managed to fix it himself.
So what do you think? Please?
Before I try to take it to a Citroen Garage and pay through the nose.
Stan

[Ozvtr]

I don't actually know what the P1336 code translates to but it's no doubt a misfire code.
Does the car run fine now? You didn't say.

A misfire is typically associated with fuel or spark.
The coil pack (in the TU4JP5) consists of 2 coils. 2 connections to positive and 2 wire connections to the engine ECU. If one of the power wires' insulation rubbed through it would blow a fuse. If one of the control wires rubbed through but only made intermittent contact to ground it would run a bit badly (have never seen that).
This would be the same as the wire going from the coil negative to the points in a Kettering ignition system, rubbing on ground.
If the control wire shorted completely that would also blow the fuse.
So, yes, if you found a wire rubbed through it might cause a misfire, if it was the right wire and it was not a direct short.
Same with the injectors. If it was the wrong wire, the fuse would blow. If it was the right wire you would get an over fueling of that cylinder as the injector is driven on at random times, however the misfire would probably not be that pronounced. But I would expect another code as the fuel trims would be uncontrollable!

[Stanleysteamer]

Hi Oz
No the car does not run better, it ran as if misfiring back home, only a few hundred yards and I have not started it since, just sat inside it and put my Foxwell on it set to OBD2

The code has three things from it one of which was random misfire, The Peugeot code for this and I believe it is an engine shared with Peugeot, says "random misfire" and can be due, they say to "cabling" (i.e. wiring) or a fault in the fuelling, so presumably an injection fault. But as there is no other code I am going with it being an electrical connection fault.
Thank you very much for explaining the ins and outs of the electronic sparking circuit.
I'll check all the plugs and the cables to the coil packs sometime soon, we are very busy with other stuff at the moment.
Thanks again for the reply, I'll be interested to see what others have to say, but so far seems I am at least slightly on the right track.
I know 10/10ths of nothing about modern electronics, usually.

[Ozvtr]

One of the bad things about modern cars is that when you "talk" to them, they just give you a riddle back! It can only tell you what it thinks is happening not what is wrong! So sometimes you can be sent off on a wild goose chase if you don't keep your focus.
What happens is; the engine uses the timing from the crank angle sensor to tell whats going on. The crankshaft "accelerates" 4 times per rotation (for a 4 cylinder engine) as each of the cylinders fires. The engine ECU checks those accelerations against the angle of the crankshaft and confirms that the cylinders are firing when they should be. If they don't (for some reason) it logs a misfire code. As I said, typically it's fuel or spark that causes a misfire. Now it could be no fuel or too much fuel or a spark at the wrong time or no spark. Or some times it's "duff gen" (sorry, my father was in the air force, WIKI it) from the crank angle sensor!
Generally speaking (but not all of the time) the engine ECU can detect a spark problem but not a fuel problem. So if it says "misfire on cylinder X" then that's probably to do with spark. If it gives you an aloof misfire code that's possibly fuel (read fuel flow or injector) related.

I would recommend going back to the old mechanic days and looking at the spark plugs. If you know how to read spark plugs, you can learn a lot about how the engine is running.
Usually, the worse the engine is running, the easier it is to find the fault.

[Stanleysteamer]

I'm 67 years old and have been playing with cars since I was about 15 . I used to run a kit car club and have built or rebuilt quite a few. I have also tuned many engines, so you could say I am an old skool mechanic.
Which is why I am confident in my skills as regards old style stuff but not so when it comes to electronix.
However I have a Discovery 2 TD5 which has a shedload of electronix hence me owning a Foxwell Pro 520 diagnostic tool. It is set up for Jaguar Land Rover products but also has a basic OBD2 reader.
So I was going to start with plug removal, etc.
Sadly I am in France at the moment and do not have things like my compression tester with me as they are in the UK. But I do have a multimeter. And lots of other tools. (Not a short holiday, in my holiday home. But going back on the 22nd, fortunately we put the car on a trailer anyway, so as long as I can get it onto it.....................! (Don't have a winch!)

[Ozvtr]

Ach! Your only a few years older than me. So you should still a few new tricks in you.
The TU5JP4 engine, thankfully, has minimal sensors in it to go wrong. So finding problems with it is not that hard. Well, not much harder than the old school engines. If you can trace a circuit diagram, operate a multimeter, trace wires, find short or open circuits, blown fuses and know how an engine works in the first place, then you can fault find this engine!
Keep your mind open and don't think that all the potential problems on this engine will be with the electronics! Not all problems turn out to be short circuits and dud sensors.
Remember; suck, squeeze, bang, blow!

[Stanleysteamer]

I think we are singing from the same hymn sheet!

[Stanleysteamer]

Well I dug deeper into it today.
took all the plugs out, all gaps were a little too wide so I regapped them, three were very clean, number 4 was a little sooty.
I also took the nearest (exhaust) cam cover off and had a look wondering if I could see any evidence of a sticky valve, nothing doing there but to really sure I would have to take the camshaft out.
As the car starts and runs albeit with a strong misfire and a smell of petrol I think the coil pack is failing on number 4 cylinder. But I have no way of testing it. I am also not happy at running it like this because of what it must be doing to the Cat.
So I will ring a local Citroen garage we have used once before and trailer it to them hopefully.

[C3CAR]

Coil packs do break down eventually.

Would it be worth just changing it? You could save yourself from the Citroen garage and a tow charge?

[Stanleysteamer]

I'd be trailering it myself anyway, so no charge there.
But I have always been very unwilling to fire the "parts gun" at a problem. If they tell me that is what it needs then I might just say "OK then" and order one off them. But I'd rather have it confirmed. Anyway it is the wife's car not mine so if I ordered it fitted it and it didn't solve the problem I'd never hear the end of it.
She usually trusts me with anything to do with our cars but she gets kinda tetchy if she "needs it" in a hurry, and she is willing to pay garages, whereas I am very loathe to.
What time is in in Oz land?