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scott87

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I've just got my twingo 1.6 and it has a misfire. It only occurs when at idle. Driving is completely fine. Basically the car shakes quite a bit at idle, when the revs drop with the control valve im guessing, the misfire does seem slightly not as bad.

I have taken each coil pack off one at a time and swapped with a brand new one, then moved to the next etc. This made no difference. I'm just wondering what else could be the cause of this. The plugs look brand new but i am about to drop another set in. I just want a heads up to what else it could be as im meant to be driving 200 miles later tonight.

Mpg wise the car is getting around 45 miles to one of the digital blocks.
 
what's the idle speed currently sitting at when warm scott? it should be 800
 
oscar":37tunync said:
what's the idle speed currently sitting at when warm scott?
Click to expand...

Its under 1k, id probably say around the 800mk, maybe a tad lower. It seems exactly where i would have set the control on my Supra if that helps at all, as in to me it seems normal.
 
Im wondering if the spark plugs dont fix it, could it be the lambda sensor? Although would this not throw a warning light onto the dash?

I have a standard 1 lead lambda, would this be suitable for the car or does it have to be a specific one? The one i have was a fortune as it is made to handle hotter than normal temps.
 
no, it's a 4 wire sensor you'll need. if it was your pre cat oxygen sensor then your fuel economy would be all over the place wheras right not it's spot on at roughly 40 miles to each bar. personally i think you're going to waste a huge amount of money just throwing random parts at it without a proper diagnostic process which doesn't really cost you much money, i mean you know how to test the ignition system and how to rule out wether or not it's the spark plugs, or the coil leads and you've ruled them out it appears.

plug your diagnostic machine in, if it's a cheap ebay thing don't bother - don't waste your own time! check the live sensor data, if the oxygen sensor bank 1 is all over the shop then it's going to be your pre cat oxygen sensor (the one in the manifold). if it's reading smoothly between 0,1 and 0,9 but most usually on renaults this will be between 0,2 - 0,8 but the first 2 sets of range values are just about fine. test this over different throttle conditions also. what is your bank 1 & 2 fuel trim currently at? and are the sensor values for everything else fairly stable, nothing darting and spiking all over the place?

while you're there, the next things you'll need to do is do a pressure test on the cylinders, around 180 psi is good. 150 is okay, below that and you're in trouble. dry and wet test the cylinders to distinguish wether or not you've got a valve problem or piston ring problem! cars are fun, but buying crashed cars is something that even i'd say no no no no to. you are a brave boy :p

obviously i appreciate you're into your cars and do a lot of your own work so i'm making the assumption that you have this kind of tooling available to you to carry out this sort of diagnostic procedure
 
oscar":1p4ux3d9 said:
no, it's a 4 wire sensor you'll need. if it was your pre cat oxygen sensor then your fuel economy would be all over the place wheras right not it's spot on at roughly 40 miles to each bar. personally i think you're going to waste a huge amount of money just throwing random parts at it without a proper diagnostic process which doesn't really cost you much money, i mean you know how to test the ignition system and how to rule out wether or not it's the spark plugs, or the coil leads and you've ruled them out it appears.

plug your diagnostic machine in, if it's a cheap ebay thing don't bother - don't waste your own time! check the live sensor data, if the oxygen sensor bank 1 is all over the shop then it's going to be your pre cat oxygen sensor (the one in the manifold). if it's reading smoothly between 0,1 and 0,9 but most usually on renaults this will be between 0,2 - 0,8 but the first 2 sets of range values are just about fine. test this over different throttle conditions also. what is your bank 1 & 2 fuel trim currently at? and are the sensor values for everything else fairly stable, nothing darting and spiking all over the place?

while you're there, the next things you'll need to do is do a pressure test on the cylinders, around 180 psi is good. 150 is okay, below that and you're in trouble. dry and wet test the cylinders to distinguish wether or not you've got a valve problem or piston ring problem! cars are fun, but buying crashed cars is something that even i'd say no no no no to. you are a brave boy :p

obviously i appreciate you're into your cars and do a lot of your own work so i'm making the assumption that you have this kind of tooling available to you to carry out this sort of diagnostic procedure
Click to expand...

Thanks for all that info.

Unfortunately i do not have all of that equipment at my disposal. Toyotas you can self test them by bridging ports and getting error codes back that way and that is normally enough to narrow down the problem. The shunt was very minor and i would imagine a pot hole to have been a bigger impact so im hoping that there is no headgasket or piston damage.

The oil and coolant are both spot on and neither have faltered at all so far. Nor is there any residue around the oil cap or coolant cap. No smoke under any conditions either.

I do have a slight oil leak but im guessing this is just a rocker gasket as it is form the top of the block from a place i cannot see.
 
Ok i have changed the spark plugs and the misfire is still present.

when i rev the car and let the revs drop the misfire/juddering is worse, then as the revs come to settle again the misfire calms down. There is still not smoke, oil consumption etc.

Im wondering if this must be a sensor issue? Surely a headgasket would cause issues all over the place and not just on idle.

Here is a picture of the plugs anyway. They needed changing and im currently uploading a video of the engine running. Im really stumped on this one! When i was pulling the leads from the coils again just to check, i got back in the car and the spanner light was on, also the traction control. Turned the engine off and back on and this had gone away so assuming that was just from me fiddling.

Does anyone live near me with a bit of diagnostic kit or am i going to have to dig deep and take it somewhere? Can i not pull error codes from the car in any other way?
 
bought it privately as a cat c or d write off i believe mark!
 
If disconnecting one of the coils made slightly less difference than the other three and youve already changed plugs and swapped coils over without any change, its much less likely to be ignition based.

The plugs shown above are the tripple electrode -7 ones, so the correct later ones.

A leaky or blocked injector?
Air leak into the manifold? Is there a quiet high pitched hiss or whistle when the throttle is closed, which is when manifold vacuum will be greatest. Once the throttle opens, theres air entering through the throttle so small leaks are less apparent under normal running under load
 
singlespeed":3mjhhjbe said:
If disconnecting one of the coils made slightly less difference than the other three and youve already changed plugs and swapped coils over without any change, its much less likely to be ignition based.

The plugs shown above are the tripple electrode -7 ones, so the correct later ones.

A leaky or blocked injector?
Air leak into the manifold? Is there a quiet high pitched hiss or whistle when the throttle is closed, which is when manifold vacuum will be greatest. Once the throttle opens, theres air entering through the throttle so small leaks are less apparent under normal running under load
Click to expand...

This is true. At least now i have a nice set of new plugs in the car anyway and a spare coil pack should one develop a fault!

I wondered about an injector but thought this would cause running issues too not just at idle?

Ill post a video when i can of the engine running, but to me it sounds normally. I mean they are noisy little engines anyway so i'd imagine an air leak would be hard to find.

I was thinking also perhaps there is a maf or map sensor? this could cause an idle issue.

Or

The oxygen sensor as mentioned, but i'd expect a warning light from this.

Or

I have read that Renault are notorious for requiring the injector signalling to be reset or calibrated at the ecu, as this can be thrown off from other faults?

If though i need a diagnostic, where is best to go. Apparently the Renault dealer healer is a nightmare to deal with.
 
A blow torch can be used to reveal an air leak (if there is one). On a fairly cold engine, Turn on the blow torch but don't light it, leaving it blowing out gas... point the gas stream at any joints from the throttle body, map sensor, brake servo connection and around the upper lower manifold joint and injectors. An increase in idle speed would be caused by the extra fuel (gas) being drawn into the manifold and contributing to that supplied by the injectors.

You can use carb cleaner but the residual liquid causes a greater fire hazard, especially on a hot engine
 
singlespeed":1kcbbtg3 said:
A blow torch can be used to reveal an air leak (if there is one). On a fairly cold engine, Turn on the blow torch but don't light it, leaving it blowing out gas... point the gas stream at any joints from the throttle body, map sensor, brake servo connection and around the upper lower manifold joint and injectors. An increase in idle speed would be caused by the extra fuel (gas) being drawn into the manifold and contributing to that supplied by the injectors.

You can use carb cleaner but the residual liquid causes a greater fire hazard, especially on a hot engine
Click to expand...


don't go wild with carb cleaner though, as much as i recommend everything above make sure you don't go wild throwing can after can after can in lol as you are effectively injecting fuel + extra fuel with the brake cleaner or carb cleaner which are both really the same thing. the days of carburators are gone :D i remember i blew a catalytic converter after one big can of brake cleaner. still to this day haven't got a clue what happened, but i found out the hard way that cat's don't like brake cleaner and neither do DPF's
 
Having a diagnostic run as we speak :)

Also thinking of removing the rear backbox and welding the tip onto the new pipe I make. Has anyone done this?
 
Ok diagnostic done.

My mate reckons it is very unlikely to be a headgasket or piston ring issue.

These are the codes that we pulled. We also checked the vac system and as there are so few pipes related to the fuel system this all looks ok.

The codes are:

p0300 Multiple cylinder midfire detected

But this appears to be caused because of this code:

p0313 Misfire detected with low fuel

We have chucked a bottle of fuel additive into the car just to ensure that there isn't a blockage. But im a little lost as to what this could be. Injectors normally stick open so i wouldn't have thought this to be the case.

Any help would be much appreciated.


*Edit*

Just read that the coils are connected in 6v series, so if one is down it will drag a good coil down too. So my check with one coil wont have helped, if more than one coil was playing up. I need to change coils 1 & 4, then 2 & 3 together. Then this would confirm whether or not the coils are to blame.
 
I had this problem on mine a bit of redex cured it but it comes and goes
 
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