Citroen C2 1.1 Idle Misfire [SOLVED]

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

moizeau
Donor 2020
Posts: 964
Joined: 12 Jan 2015, 17:08
x 131

Re: Citroen C2 1.1 Idle Misfire

Post by moizeau »

Not knowing the engine or layout, so may not be possible? Could you make up an '360 degree angle finder' and fix it near the camshaft sprocket, turn the engine over by hand with a DTI on the cam lobes and mark what angle each cylinder reaches TDC, then do the same down the spark plug hole on the piston.The marks on the angle finder, relating to each cylinder, should prove or disprove the cam ( in theory).

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

Thanks Pete. Yes that is something that could be done. In years gone by I have built and tuned engines and one thing I had to do was 'dial in' modified cams. Your method is the way it was done although the 360 disc gets bolted to the crank. Small changes would be made to allow getting the cam timing spot on. Offset dowels, keys, or vernier cam pulleys would be used to achieve this depending on the engine's valve gear configuration.

Unfortunately I have not been able to get any data for the cam. No lift information or duration figures. I did get lift data for the hdi cam but nothing for mine.

I did manage to compare a pic of the hdi cam and the one in mine, and it's visually obvious the difference between them both. Based on pics alone I am expecting to find the cam in mine is a regular ground cam and not a pressed on lobe type. Apparently the lobes are not actually pressed on. They are slide onto a hollow shaft then hollow section is broached.

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

I took a look today and it's actually very hard to view the cam but I saw enough of it to ascertain it's an old school cam. So it looks like the lobe theory is put to rest.

Next I want to check the fuel pressure at idle. Hopefully the part I need to do that will arrive in the next day or two..

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

An interesting development...

I mentioned I had noticed the revs bouncing up when coming to a halt and idle.. Today when out on a test drive it started revving up when changing gear. Instead of the revs dropping between gear changes they rose by maybe 1500 revs.

On my return I tried depressing the clutch pedal and could hear a very light clicking sound. It turns out there is a switch on the clutch pedal. As yet I have been unable to find out the purpose on my particular car. Generally it's for not allowing you to start the car in gear. On my other car, a BMW, I have to depress the clutch first before starting otherwise it will not start.

On my Citroen I am unsure if it's supposed to do the same or it's purely there to stop you starting it in gear. After a bit of hunting around I found folk on VAG forums having this over rev situation I am experiencing and the clutch switch is the culprit.

Anyone experienced this on a Citroen??

Tomorrow I am going to try and get the switch off the pedal box. It looks an absolute nightmare to get at.

Now here is where it gets rather interesting.. I began to wonder if this might be related to the misfire. A hunt around the Google led me to a Triumph bike forum where they were discussing their bikes having misfires after doing a delete of the clutch safety switch. Apparently it creates a whole host of issues and not just misfires. You can see where I am going with this :lol: Ok it's maybe wishful thinking but just imagine that turned out to be the cause of my misfire!

Hell Razor5543
NOT Alistair or Simon
Posts: 10479
Joined: 01 Apr 2012, 09:47
x 982

Re: Citroen C2 1.1 Idle Misfire

Post by Hell Razor5543 »

I know my C5 has a clutch pedal switch as well. I believe it is for engine management processes. I KNOW that (if you have cruise control) it will cause the cruise control to disengage if you touch the clutch pedal.

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

Thanks James. I would have thought it was relevant for cruise control as well but I don't have that. There is no mention in the owners manual of anything relating to it. Last night I searched the wiring diagrams for the car on Sedre and could not find the switch on them at all. Some people are saying on other forums it gives the ecu a signal to cut off the fuel.

I removed the switch this morning. What a carry on to get that out. Had to partially remove the clutch pedal. No room to work and switch is totally hidden within the top of the pedal box.

I did a continuity test and found it to be intermittent in continuity. I considered opening up the switch but it looked like it would get destroyed trying to do that, therefore I gave it a blast of contact cleaner. That seems to have done the trick. It's now operating with less plunger travel and no longer intermittent. The refit was not any easier..

Test run next.. :-D

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

Latest update..

I have been running the car for a few days and so far it's looking like the clutch switch cleaning has sorted the over revving between gear changes.

It has made no difference to the misfire though. It still remains. There are a couple of things I have discovered. I removed the throttle body for another inspection. It's spotless as I have cleaned it before. The body in mine is a VDO one and it's incredibly simple compared to other brands. There are no gears at all. It's a direct drive on the throttle shaft. I did discover there is a bit of play in the throttle shaft. It's possible it could be drawing air in through the gap at idle. However, having researched how a MAP sensor system reacts to vacuum leaks it appears the ECU will compensate unlike a MAF system. A MAP sensor measures pressure. Any changes in pressure the ECU will adjust for.

Probably the most significant discovery has been during night driving. The idle is significantly better to the point that I would say it was pretty darn close to perfect.
The extra load on the alternator with the lights on has to be the key. I believe the ECU will compensate for the lower idle created by the extra mechanical drag on the engine due to the higher load on the alternator and raise the idle to the predetermined norm.

As to why that improves the stability of the idle, I as yet don't know.

I really need to be able to get more data beyond the capabilities of the diagnostic software I have. Lexia is a possibility but I don't want to fork out for a diagnostic head only to find out it has limitations regarding live data.

I have the opportunity to connect the car to a Snap On diagnostic tablet so I think that is likely my next move. I am in no rush as apart from the lumpy idle the car runs well and is returning fantastic fuel consumption. The next update could be a while yet..

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

Yesterday I had the opportunity to visit an old friend's garage. Prior to travelling there I had stopped off at the shops on a quick errand. I was no more than five minutes and on my return to car it would not start until I gave it some gas. That's the second time that has happened with the exact same scenario. Might be related to my misfire or something else also.

Another issue I have had on three occasions is the central display flickering like crazy when ignition is switched on. Each time a BSI reset has cured it.

This car has issues!

On arrival at my friends garage we hooked it up to his MoT gas analyser. At idle it was showing it was running lean. Above idle and beyond we conducted a few tests holding it at set rpms. In every instance the readings were absolutely perfect. Lambda was right on the money, hydrocarbons in low single figures and Co figures barely off zero.

The next thing we did was connect a Snap On diagnostic tablet to the car. There were two fault codes my own scanner had not picked up on relating to the alternator. P1675 and P1676. I think they might be related to the time I was running some tests with the alternator. We cleared the codes and they never returned. Apart from those there were no other current or pending codes.

A day earlier I had conducted a static and running fuel pressure test. Static and running produced 3.5 bar which is absolutely spot on.

We decided to have a look at live data and that proved to be a mixed bag. Upstream and downstream o2 were reporting a lean condition in keeping with our gas analysis. I then wanted to look at injector pulse widths. The figures were remarkable. Number one was 18ms. Cylinder 2 was 116ms. Number 3 was flatlined at 208ms. Finally, number 4 was 43ms. The intake temperature was pegged at -60 and spark advance was something ridiculous like -40 degrees.

If the figures were correct on injector pulses it would be running awful and be down a cylinder on number 3.

I am not buying those figures. The Snap On tool is either not interpreting data correctly or my ecu is messed up. On reflection I think I should have tried generic OBD PIDs on the tool.
I am returning to the garage later in week so I think I will try generic PIDs this time.

One positive step is I know the fuel pressure is good. As to that occasional starting problem it's possible the fuel check valve is not holding pressure. I did a very brief test for that and the pressure dropped from 3.5 bar to 2 bar in 15 secs. I need to revisit that again as I need to check it over a longer period.

Nemo26
Posts: 59
Joined: 19 Apr 2017, 09:26
x 3

Re: Citroen C2 1.1 Idle Misfire

Post by Nemo26 »

The way that you try to fix your car is not good. Missfire can ocur if engine miss spark, fuel, or compression. First of all make rpm drop test. When engine iddling, disconect spark plug harnes one by one and look for rpm drops. Identify missfiring cylinder, and than report here.

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

Nemo26 wrote:
03 Apr 2019, 20:05
The way that you try to fix your car is not good. Missfire can ocur if engine miss spark, fuel, or compression. First of all make rpm drop test. When engine iddling, disconect spark plug harnes one by one and look for rpm drops. Identify missfiring cylinder, and than report here.


I agree but the setup of the coil pack would drop two cylinders at a time as the coil pack has one coil per two cylinders. Its a wasted spark ignition,

I did manage to pull the leads to number one and four cylinder injectors and misfire was still there. I need to try and get two and three off but they are impossible so far to remove. So its either misfiring on two or three but I need to get them unplugged to be sure. Might be across all of them ie a fuel issue.

User avatar
NewcastleFalcon
Posts: 11572
Joined: 25 Feb 2009, 11:40
x 1015

Re: Citroen C2 1.1 Idle Misfire

Post by NewcastleFalcon »

Dibber...

Reading this thread here from the C2Club.co.uk it seems you are not alone.... Unfortunately it may not be that helpful to you. It's one of what I would describe as a typical "misfire" problem thread, plenty of could be this could be that and no resolution by the "last post"!

http://www.c2club.co.uk/showthread.php? ... 8755f4c832

REgards Neil

Nemo26
Posts: 59
Joined: 19 Apr 2017, 09:26
x 3

Re: Citroen C2 1.1 Idle Misfire

Post by Nemo26 »

Can you look with osciloscope secundary ignition pattern? That will reveal lean condition missfire also.

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

NewcastleFalcon wrote:
05 Apr 2019, 00:10
Dibber...

Reading this thread here from the C2Club.co.uk it seems you are not alone.... Unfortunately it may not be that helpful to you. It's one of what I would describe as a typical "misfire" problem thread, plenty of could be this could be that and no resolution by the "last post"!

http://www.c2club.co.uk/showthread.php? ... 8755f4c832

REgards Neil


Thanks Neil. I had already seen that post. My friend that worked for PSA said anytime they had a misfire and had to call the PSA technical help, the first thing the guy he dealt with asked was, had it bosch spark plugs fitted. He would refuse to address the problem until bosch spark plugs had been fitted. I had NGK in the car but I switched them out for Bosch.

Threads I have read on other diagnostic forums say it's imperative to fit dealer coil packs and in my particular engine it has to Bougicourd/ Electrifil brand. Sagem coils should be ditched. They are also known as Valeo or Johnson Controls. My friend disagrees about Sagem. He said there was issues with them when the 206 first came out. There was a factory modification involving splicing into a coil pack wire and putting what sounded like a capacitor connected to the coil wire and earth. However he said that was quickly resolved. I assume by modified coil packs.

The TU engines do not have camshaft sensors on them, other engines may be the same. They use what is termed as phase detection. It's basically that the ECU detects differences between the sparks on cylinder pairs. As there are only two coils within the coil pack it operates a wasted spark ignition. Effectively what that means is a spark occurs twice 180 degrees apart within the cylinders combustion cycle. As number one fires, a spark occurs also in number four when it's at it's opposing cycle to number one. Under compression the spark generated is far greater than the opposing cylinders spark and this difference is detected by the ECU thus allowing it to know what position in the cycle the piston is.

So.. it stands to reason with the ignition process being so critical to determining the position of the piston, any anomalies in its operation will have an adverse effect on the running of the engine. That is why I think the coil pack and choice of spark plugs are critical in these engines.

As you say Neil it appears to be a common unresolved problem..

Dibber
Posts: 56
Joined: 19 Mar 2019, 11:26
x 4

Re: Citroen C2 1.1 Idle Misfire

Post by Dibber »

Nemo26 wrote:
05 Apr 2019, 08:16
Can you look with osciloscope secundary ignition pattern? That will reveal lean condition missfire also.


I don't have access to a scope Nemo but yes you are right that would be helpful. I have even considered buying a small scope..

I need to figure out if this is across all cylinders or one or even two. I am going to try establishing that next.

Nemo26
Posts: 59
Joined: 19 Apr 2017, 09:26
x 3

Re: Citroen C2 1.1 Idle Misfire

Post by Nemo26 »

I'm sorry, but I can't help you any further. Your only chance is to try to unplug leads to identify missing cylinder, or if your car is under OBD2 standard to check under mode 06 missfire monitor.