Clio 16Valve misfire/bunny hopping

Newbie Joined: 12 Feb 2005 Posts: 14

Hi all, I have been reading your forum for a few months now, and its been very helpful, however I have now got a problem with my 16valve that I haven't been able to pinpoint in any searches.
For a while now the car has been idling erratically from a cold wet start, revs dropping so low that it would cut out, as soon as I start going though everything is fine after about 2 mins driving.
In the past few days though, the problem has developed, now whilst driving along at a constant speed, if I ease off the throttle slightly, the revs will drop quickly, then correct, then drop again causing a kangarooing motion and some violent engine shakes, this will happpen at any speed, and when coming to a stop with clutch dipped it usually cuts out. If I can keep the throttle on all the time it doesn't seem to do it.
I believe its a moisture related problem because it started on thurs morning after a wet weds night, it did it all the way to work and all the way home. However after driving home, stopping for 5 mins and setting out again the problem had more or less gone, until it started again last night on the way home from work (it was wet).
I have in it already almost new plugs, I have ordered new leads, dizzy cap and rotor arm, and a CTS (coz I know this can cause a lot of problems). I have checked the coolant level and it hasn't dropped, and there is plenty of oil too.
I hope its something like a HT lead or something, but I was wondering if anyone else has had a similar problem and could suggest something else that it could be.
Sorry for the long post but I am trying to give as much info as possible for the renault genius' amongst you to solve my problem.

Also I have recently cleaned the throttle body and ISCV.

Thanks

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

check the plug wells for water. Its more a 19 than clio problem but water can still get in there.

If theres water in there remove it, use a squirter from a windowlene bottle or something.

It may also be the TPS. If you acelerate slowly but going to full throttle does it go fine then suddenly lose power and pick up again?

Newbie Joined: 12 Feb 2005 Posts: 14

If accelerating it seems fine, although when first setting off it will lose power then pick up again.
I will check the plu wells later, however if it doesn't rain it may have cleared up by then.
Also another problem, i don't know if this is related, if I go over 5krpm, in say 3rd gear accelerating to 70, when I come to a stop the car won't idle below about 1400rpm. I have added another earth to the road speed sensor (black wire, I hope this is the correct one) but it hasn't made any difference.
Also could general poor earthing be causing my original problem, could the effect of poor earthing be enhanced by moisture?? this is just another thought because I am planning to sort out the battery terminals and earthing in the engine bay too.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

well dodgy earthing won't help anything at all

so get that sorted.

Newbie Joined: 12 Feb 2005 Posts: 14

My original problem has re-occured and developed into a much worse problem, The car refuses to start now!!!!
I replaced ht leads and dizzy cap and rotor, the car had got back top running ok at this point, and continued to run ok until thursday night. I don't believe its moisture related anymore as the misfires (if thats what they are) re-occured in the dry.
Another common factor which I have found is that it started to happen again when the fuel level went below 1/4 as I believe it did before. Now this is the 2nd tank of fuel the car has had since embarrasingly running out of petrol 2 weeks ago, so I'm guessing that my problem is related to this.
I myself have 2 possible solutions, which I'm gonna have to try, could you please guide me if I am barking up the wrong trees!

1. The fuel filter is getting clogged and because I ran out of fuel and there is loads of shit in it and when the fuel goes below a certain level the pressure my drop slightly causing the engine to be starved of fuel???

2. Running out of fuel clogged/blocke/fooked up my cat (i have read this in a manual), as the car will no longer start I have carried out a test by removing a spark plug to let the exhaust gasses escape that way (as directed by a haynes manual) it fires and seems like its about to start then doesn't.

I'll be grateful for any help, thank you

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

1. Doubtfull but its worth a change. I usually find its not so much the paper element that clogs on the replaceable filter (change it anyway) but more the pick up strainer on the pump. This wore my chammys original pump quite a bit.

2. No won;t have happened unless it ran very lean then melted the core, go under and give it a thump with your hand. If it rattlesd or bounces about yes its buggered.

Also how can any engine no matter what it is can make a noise like its goign to start with no compresion spark plug? If you can master this then my good man you will be the richest man alive.

Is the fuel pump priming when you turn the ignition on?

Newbie Joined: 12 Feb 2005 Posts: 14

yes the fuel pump primes.

I only removed one of the spark plugs, and it made a sort of puffing noise, and it sounded as if it started for a split second. I'm no expert its just what I read in the Haynes Engine Management manual where it said if the cat is blocked, remove a spark plug and exhaust gases willk escape through the spark plug hole and the engine will probably start, so I gavce it a go!
Wouldn't it just run on 3 cylinders, or am I just being silly?

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

yes but the haynes in there usual stupidity failed to tell you that raw fuel will be injected and pass out not only the spark plug hole but run down to the cat and ignite in there further making things go tits up.

I also thought you removed more than 1 plug.

Have you tried starting it with the throttle fully open?

Newbie Joined: 12 Feb 2005 Posts: 14

battery is pretty dead now, I did try pressing the throttle a bit, but I don't think I actually tried it fully open. I'm just gonna list all symptoms etc. in order and what I have replaced, maybe you will pick more up from there. As reading through my last posts they are a bit long winded.

- 2 weeks ago ran out of fuel.

- Filled up tank car ran fine, started 1st time etc.

- Tank dipped below 1/4 tank (also a rainy day) car started to drop revs suddenly whilst trying to maintain constant speed and hesitate.

- This got progressivly worse and car was cutting out when stopping at junctions and juddering quite severely when easin slightly off throttle.

- Filled up with fuel and problem persisted.

- Replaced battery terminals, cleaned up and added new earthing to engine.

- After the car was sat idle for a day and a half, car started fine and engine was running fine for 3 days.

- Replaced leads, dizzy cap and arm, and CTS (as I suspected a moisture problem).

- Car carried on running fine until I think the fuel dropped below 1/4, then the judder/misfire came back, not as frequent, but getting worse (in the dry this time)

- Filled the fuel up again thursday night, juddering still there.

- Car started fine Friday morning, went to work, still juddering not at its worse.

- Drove home from work fiday afternoon, still juddering, got worse, car cut out at a junction and wouldn't restsart, pushed it round the corner and it started again. Parked up outside house.

- Went start car this morning, it started twice very briefly, didn't give me chance to rev it to keep it going.

hope this is a better summary of my problems and you can deduce something more!

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

If the batteries nearly dead then the car will not start.

The reason the car doesn't fire right away (i'm talking normal behaviour here) is the engine has to be spinning at a pre-determined speed for the ECU to power up, so if the things barely cranking over the ECU will not power up and the car will not start. So if the batteries spinning it over slowly then theres no chance of it firing.

If you have been repeatidly trying to start it and its nearly gone chances are its pretty flooded by now. The inlet manifold btw will fill up with petrol and pour out the throttle body, thus happened to me on the white 19, unplugged the injectors and it ran for about a minute.

With the throttle fully open it stops the injectors firing, flooded engine start procedure (however not all versions have this).

Anyway, have you opened the petrol cap?

Newbie Joined: 12 Feb 2005 Posts: 14

yeah battery is pretty flat, gonna use jump leads when I come to try and start it again.
Will probably be tomorrow now, I'll try it with throttle fully open to clear out the throttle body.
Also I've got a new fuel filter so i'm gonna replace that anyway.

I haven't tried opening the filler cap, what will this achieve?

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

well if you have a breather problem for the tank it can create a vacuum when this happens as the fuel is used the tank tries to implode, on a plastic clio tank its ok, on metal ones they crumple. But it causes fuel starvation as the tank gets low.

Another rason could be a damaged fuel pump, when its submerged in fuel its fine, but a split in the housing thats exposed as the level drops may prevent proper delivery.

Newbie Joined: 12 Feb 2005 Posts: 14

Ok, I'll give this a go too.
and if it doesn't get any better I suppose I'll have to start investigating the fuel pump.
Not looking forward to that as I don't fancy dropping the whole fuel tank!
I'll let you know how I get on.
Thanks again

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

I should word that better, a plastic clio tank will just deform in the way, whereas a metal tank crumples like an empty coke can.

But you get the same problems.

It would also tie in with the fact it was crap the night before but ok the next morning then going home after work it was worse again. As the longer its left the more the pressure equalises to atmospheric.

But it only applies if this is the problem.

Newbie Joined: 12 Feb 2005 Posts: 14

I jump started the car just now, first time i've touched it since yesterday morning, held the throttle down fully and it started first time no problems and idled perfectly!!
I didn't try opening the filler cap, although I have left it over 24 hours, so as you said the pressure could have equalised, I will try driving it soon and see how it feels, and i'll change the fuel filter today, seing as I have one ready.
From what you have said about pressure build up and breather problems, it seems quite likely that this is my problem. How can I remedy it? does the fuel tank have brether hoses etc. that I can remove and clean up, or is it a more complex system?

Newbie Joined: 12 Feb 2005 Posts: 14

Thanks for all your help Chris.
I've finally pinpointed my problem, it turned out to be nothing to do with fuelling at all!
I discovered that after I had got it running on sunday it was going perfectly, then I drove to my birds house, all was fine, til I hit some windey country roads, every left hand bend I took, no matter how tight caused the rev counter to read 0 and I couldn't apply any power until I got the wheels straight again.
Car did the same thing monday on way to work and wouldn't start again on the way home, I assumed that I was some sort of electrical problem, so I started wiggling the wiring harness on the drivers side of the engine and got the car to start again, wiggled it with the engine running and made the car stall........ bingo, found the source of the problem.
This evening I investigated further and noticed that to the side of the power steering reservoir the wiring harness was bare (no casing) so I pulled it out and inspected it and 4 wires had nicks in with copper showing. Below the harness there is a some sort of pressure sensor I think and the wires for this had almost snapped.
I've patched up all of these wires and taped up the main loom and the car seems to be running fine now...........thank fook.
Thanks again for your help, I'll be back soon with some more questions no doubt. next job left hand outer CV boot!!

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

Chris H
whats this about starting with the throttle fully open for flooded angine starting?

philgally
good luck with the CV boot...its a pain in the dick

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

all fords and some of the renix setups cut the injection if the throttles floored when cranking, it still has ignition but no fuel is added, this is to purge the fuel out of th ecylinders. I.e flooded engine over ride.

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

so if u start with the throttle fully down how long before it would decide to run normal as if u were revvin ful out?

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

well the throttle held down there will be no petrol injected so it will crank until the battery dies or the starter gives out.

Site Subscriber Joined: 04 Mar 2005 Posts: 116

for flooded engine starts I just pull the fuse for the fuel pump, then once the car is started put it back in quick.