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Discussion Starter #1
On these modern cars if a coil is going down will it cause intermittent probles such as taking longer to start and sometimes firing up on 2 cylinders? I am amazed how it will rung at such a low rpm for a couple of seconds before all 4 fire up. I thought this was just me relesing the switch too soon, but it's not starting very well from time to time so it may be something else. The MAP, crank censor and engine temp sensor are new and the plugs and filter aren't very old either. The only things that I can think of are coil and dirty throttle body. There is also that grey thing, with an electrical connector, on the front of the inlet, whatever that does.
I had a brand new oem engine tenp sensor fail a few weeks ago (9.2lt/100klm) so have replaced it with another oem one.

When the coil failed on my Marina van it would pop and bang when you tried to accelorate and so was easy to diagnose. It was also very entertaining to everyone in the street.:|
 

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Discussion Starter #3
Yeah but the coil on your marina powered all your plugs. Now with individual mini coils, if one is missing you've only got a fraction of a misfire. Good point is it'll get you home without a breakdown truck, bad point is it's more difficult to pinpoint.
Mine has a coil block with 4 HT leads coming out of it. Does it have 4 coils inside? If it does then does that mean that it only fires on the ignition stroke? Because if it does then they should last longer as they are doing less work. Or maybe there's 2 and it does the firing at top dead on both strokes.
If it has 2 then it might account for the ocasional starting on 2 cylinders, but I'm amazed how it runs and eventually fires on all 4.
 

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Super fantastic Mod Technical Supremo Nice Guy
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39,262 Posts
You wish,,, .. These fail faster because of heat, as whole unit is getting hot, not individually ....
Only problem is, is it the lead or the coil pack...
Now if one or the other,,,,, you will need leads, so it's buy the leads and try it.
If coil, you would still need leads, plus plugs,, .
That's why it's leads first, if cured, then all good, if coil pack then you will have to have plugs,,,,,,..
 

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Premium Member
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117 Posts
Discussion Starter #5
You wish,,, .. These fail faster because of heat, as whole unit is getting hot, not individually ....
Only problem is, is it the lead or the coil pack...
Now if one or the other,,,,, you will need leads, so it's buy the leads and try it.
If coil, you would still need leads, plus plugs,, .
That's why it's leads first, if cured, then all good, if coil pack then you will have to have plugs,,,,,,..
That's easy to test, just grad hold of the leads one at a time with the engine running and if your not in agony then the leads are OK. :crazy:
The coils I have looked at, on line, all seem to come with the leads. I've had a quote of about 30 GBP from a motor factors. I bought the crank sensor for about 8 GBP from the same place.
 

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Super fantastic Mod Technical Supremo Nice Guy
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NOOOOOOOOOOOOOOOOOOOOOOOO,, dont do that on any car after 1999..
They do not work that way,, that is what spikes the injector ECU, it has chokes inside it, doing that will fry one, and you will need an ECU, maybe not at the time, but within a couple of months ....
If going to test , use a lead that goes over the spark plug, and shows the circuit working....
 

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6,622 Posts
On these modern cars if a coil is going down will it cause intermittent probles such as taking longer to start and sometimes firing up on 2 cylinders? I am amazed how it will rung at such a low rpm for a couple of seconds before all 4 fire up. I thought this was just me relesing the switch too soon, but it's not starting very well from time to time so it may be something else. The MAP, crank censor and engine temp sensor are new and the plugs and filter aren't very old either. The only things that I can think of are coil and dirty throttle body. There is also that grey thing, with an electrical connector, on the front of the inlet, whatever that does.
I had a brand new oem engine tenp sensor fail a few weeks ago (9.2lt/100klm) so have replaced it with another oem one.

When the coil failed on my Marina van it would pop and bang when you tried to accelorate and so was easy to diagnose. It was also very entertaining to everyone in the street.:|

probably found anyone with a Marina van entertaining, probably looking to see if Jeremy Clarkson or any piano's were lurking ! :grin2:
 

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Super fantastic Mod Technical Supremo Nice Guy
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Now you have cured your cannister issue,, are you sure an injector is not leaking over night, flooding a spark plug.
How about leaving it over night, and before starting it, taking plugs out and looking inside the bores,, will show wet on top of the piston, if an injector is leaking
 

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Premium Member
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117 Posts
Discussion Starter #10
NOOOOOOOOOOOOOOOOOOOOOOOO,, dont do that on any car after 1999..
They do not work that way,, that is what spikes the injector ECU, it has chokes inside it, doing that will fry one, and you will need an ECU, maybe not at the time, but within a couple of months ....
If going to test , use a lead that goes over the spark plug, and shows the circuit working....
I have brushed my hand against the HT leads on a motorbike in the rain years ago and it's not something that I want to repeat.:surprise:
 

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Super fantastic Mod Technical Supremo Nice Guy
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These are a lot more powerful now.
Have had people crying when I have diagnosed cars and found out they have fubarred the ECU ....
Sending the spark to earth, would be ok, but using the engine that is Earthing the ECU,,, bit like welding a car with the battery connected
 

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117 Posts
Discussion Starter #12
Now you have cured your cannister issue,, are you sure an injector is not leaking over night, flooding a spark plug.
How about leaving it over night, and before starting it, taking plugs out and looking inside the bores,, will show wet on top of the piston, if an injector is leaking
Intersting, but the time when it took 4-5 seconds to start it never even tried to fire up, not even a cough. The times when it has fired on 2 is when I have flicked the key and it hasn't started as fast as usual so I have let the key go too soon. It doesn't seem like wet plugs as I think it would chug more at the start when it does fire up. It's seems to be on 4 anfter and extended cranking time or on 2 after I don't crank it for long enough i.e I hear it fire once and let go of the key when it needed another revolution or 2.
I'll know more tomorrow morning.
I'm still seeing how it goes after the rest, but after only a few miles and a few starts it 'seems' better and the mpg has improved again, but then if it's a random problem.....I'll know more tomorrow, I hope.
Oh, I booted it on a fast road the other day and it went to 150klm/hour whereas before in the same place it would only do 130klm before th new stuff, so it's a lot better when it's running. No misses or farts at all.
Maybe I didn't disconnect the battery for long enough when I changed the crank sensor(I was in a hurry) and maybe after this time it will be OK?
 

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Discussion Starter #13
These are a lot more powerful now.
Have had people crying when I have diagnosed cars and found out they have fubarred the ECU ....
Sending the spark to earth, would be ok, but using the engine that is Earthing the ECU,,, bit like welding a car with the battery connected
But don't the plugs earth to the engine?
 

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Super fantastic Mod Technical Supremo Nice Guy
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39,262 Posts
Not quite, as the ecu is switching off,, and it needs this impulse to know when to fire the plug, usually off cam, or crank sensor, (abridged version)...
Its not as straight forward as it seems.... Unless a clean earth ,, it screws the
ECU up..

That was my sentiments, (they are all idiots, when told this) but over the years,, getting into the diagnostic side, bit of an eye opener...
 

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117 Posts
Discussion Starter #15
I changed the H.T. leads today for N.G.K. ones. The old ones were origonal Renault. The car seems slightly better, but I might be imagining it. I did have an imported bike from America once and that had origonal Suzuki plug caps(12-15 years old?). I bought new N.G.K. caps and tested them with a multimeter. The old caps had a lot of resistance whereas the new ones had very little. This may account for the slight change in the car as they were origonal so maybe from 2006.
Too soon to say if the problem is fixed as it is intermittent. It might be the fuel pump, although it isn't that old.
I'm going to change the fuel filter as I don't know when it was last done and with the distance I do every year it will be the last the car ever has.
Also getting a new idler pulley on Tuesday as the bearing has gone dry, by the sounds. Plus there's a little free play in it, too. I like to fix things long before they will strand me.
 

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Discussion Starter #16
Well the car still does it. The economy has gone back up after the long reset and it runs great when driving. I think it might be the new origional engine temp semsor. The last was was bad and I suspect this one, too. Infact I don't think they are Renault but copies. I'm going to try the cheap one I used to fill the gap whilst they tested the last one. The cheap one tended to rev the engine slightly too much, for my liking, at stert up, but we'll see how it starts.
I don't think a coil would run well and only be a problem at start up. The same about a fuel pump problem, too. If it were the injectors leaking then I would expect it to always start lumpy afterbeing parked for some time, but it only does this if I release the key too soon and even then it's not lumpy just turns over very slowly before it fires on 4, which would indicate no misfiring on the other two. If I let it fire up before releasing then it runs normally. So I think it might be a mixture problem, i.e. the engine temp sensor. More P'ing about and then I'll know one way or the other.
I also checked it with my code reader and there were no records of any codes and no records of any misfires.
PS I will have to wait until the engine is stone cold so I don't lose any coolant and have to bleed it when I change the temp senor.
 

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Discussion Starter #17
Changed the temp sensor back to a cheap one(5 quid) and cleaned the throttle body. It started well after this and I just let it run without touching the throttle to let it reset to the clean body. I'll let you know what happens later......I hope this is the end of it.

I'm begining to think that the Renault sensors are cheap copies as the first one was duff and now maybe the replacement.
 

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Discussion Starter #18 (Edited)
Changed the temp sensor back to a cheap one(5 quid) and cleaned the throttle body. It started well after this and I just let it run without touching the throttle to let it reset to the clean body. I'll let you know what happens later......I hope this is the end of it.

I'm begining to think that the Renault sensors are cheap copies as the first one was duff and now maybe the replacement.
UPADTE: well it seems to be OK now as it has started very quickly for the past few starts, moring and warm.
I also noticed less vibration through my feet, which I had thought was still due to the new engine mounts.
The car has regained its responsiveness which it had lost, but I thought it was me just getting used to the responsiveness gained when I changed my MAP sensor.

The second 'original' engine temp sensor was duff, too. I suspect that they were copies as to get two faulty in a row would be more than unlucky.
The first sensor work badly at normal temps and the second work badly at low temps....hence the intermittent poor starting from cold and warm but OK when hot.
Cleaning the throttle body will have helped, but the film on the inside wasn't that thick, at all, so will have had only a marginal effect on the running of the car when idling.

So even if you fit a new part that part may also be the problem. Something to bear in mind when you can't workout why it still runs badly.

If this car plays up again any time soon, then this will be me..
 
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