Bloody cage problems

[m i k e]

I took my car into a garage yesterday to get my car sorted out, it was running pretty darn rough. The fan belt needs changing (still) but yesterday I had new plugs, dizzy cap and a new ht lead installed; granted this has helped a fair bit. But, my car's still only running on three cylinders for some reason. I've been told that i've got good compression in the engine and the mechanic was saying he's a bit confused on what it could be, causing this and that it could cost a fair bit to get it working again. I don't suppose anyone would have anymore ideas on what it could be? (as I know there's some bloody good spanner monkeys on here! ) Even if people have ideas it might help me from getting my arse raped by a garage that might be trying to do me over!

The car is a 1995 renault clio 1.2L it's the c58 model which has the 1171cc engine.

Cheers,

Mike
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[Hex]

First off find out which cylinder isn't firing.

Do this by having the engin running and remove the HT leads from one plug at a time (well insulated plyers etc - not by hand!!!). If the engine changes tone/runs worse you know that one is fine, replace it and go to the next one untill you find which it is.

When you have identified the culprit, check simple things first. Ensure that the plug is firing fine (new plugs means nothing!).

If this is ok and its an older car and you can check things like tappet settings.

Let us know what you find etc.
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[steve09]

im only a first year aprentace mechnic but just a guess could it be something wrong with the fuel pump,
or maybe injector blocked ect?? maybe even a crushed pump 2 incector line,,
like i say im not professional and i work on lorry engine and big diesels which i know are slighty differnt however could be helpful i surpose,

[RascalsCustar...]

Either got to be spark, air or fuel delivery...as spark is easier to check, I'd do what hex suggested with the plugs. Single out the cylinder that's playing up, making sure that you get a good spark. Secondly...

Good compression is a good sign! Which really only leaves...fuel delivery. Arn't those clio's multi-point injection?

[m i k e]

I've not really had chance to check what Hex has mentioned yet; but, this clio has single point injection.

Mike
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[Kickstart]

Hi

DO NOT remove the plug leads like that. It will ensure that neat petrol goes down the exhaust and kills the catalytic converter. Fine to do on old cars but definatly not recommended on newer ones.

With single point injection it is likely to run on all or no cylinders with an injection problem.

If the compression is consistant between the cylinders then that suggests that mechanically it is OK. Note that you can still get good (or even very good compression) with major damage, but it would be unlikely to be consistant. For example, snap an exhaust rocker arm and the exhaust valve will not open, but it will do a very good job of compressing the air and a compression reading woul be high if anything. Same for hydraulic tappet problems.

It really does sound like an ignition issue. I would be tempted to get another set of spark plugs, as it is not unknown for new plugs to be faulty and they are cheap. Get an inductive timing light and try it on each plug lead. With luck one of the leads will not trigger the timing light.
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[Hex]

[m i k e]

The guys at the garage that changed my dizzy cap the other day were pulling the leads off and putting them on whilst the engine was running I've just asked somebody else at work whether they've got any ideas as he's pretty nifty with his mechanics and he's just said i should try a few new leads first as one of them looks pretty old and it wouldn't stay on properly, it'd just pop off after pushing it on.

I actually put new spark plugs in about a month and a half ago and they changed them the other day so I doubt it'd be the plugs Keith The guy i've just spoken to has just mentioned something about a 'Lambda' sensor? I don't have the foggiest what this does or where it's located even if my car has one! Could anyone shed any light?

Mucho Grasias,

Mike
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Bom Chicka WAHHH WAHHHHHHH!

[Kickstart]

Hi

The lambda probe is one of the things that can be damaged by dumping neat fuel down the exhaust. Basically is tells the ECU how rich / lean the mixture is (not that accuratly, but that does not matter too much due to the way they are used where the engine tends to cycle from rich to lean and back rather than trying to sit at the perfect level). Look for a thing poking out of the side of the exhaust between the cylinder head and the catalytic converter with a few wires poking out of it. Costs vary, depending on what type it is (some are heated, etc), but expect £50~£100.

Cats do not like having neat fuel dumped on them. They will survive running slightly rich for ages but even a single backfire can destroy them. Pulling the HT leads off a running engine is definatly not to be recommended unless you want a several hundred pound bill for a new cat.

I assumed you had changed the leads . If not then yes get some new ones. Probably the most likely problem. Prices vary, but should not be that much. Also check that the plugs have the bit on the top if required, and that they are securely in place.

All the best

Keith
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[MattEMulsion]

Its a Renault - thats the problem, need I say more???
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[BLOFLY 636]

another way that you could check the spark is to get hold of a new spark plug, this will be your tester, now before you start the car remove the FUEL PUMP RELAY, now start the car and wait for it to stall. Ok now it is time to remove cylinder number 1 ignition lead and attach the tester spark plug, hold the grounding terminal of the spark plug to a solid metal component of the car whilst someone turns the engine over with the starter motor while you check for a spark between the electrode and ground on the test spark plug. Reapeat this for the remaining 3 ignition leads. By removing the fuel pump relay you will not have the catalytic converter dammage issue because no fuel will be injected into the engine with the fuel pump not running. Also if you think one of the ignition leads is just hanging on then replace it, also check for white dusty marks on the ignition leads, this is a sure sign that the lead is shorting out on a metal component through the insulation, it is a common problem on smaller engines because generally the insulation breaks down easily because of the higher heat built up in a smaller engine bay. Also the Oxygen sensor on your exhaust collector pipe may not be completely useless, try removing it and cleaning it with a acetone solution like a carburettor cleaner or similar product, I had the same problem with my commodore and I had the option of paying $180 AUD for a new sensor or $7.50 for some acetone cleaner. needless to say I saved myself $172.50 the only other thing I can think of is an injector being blocked or not opperating at all check the wires on the injector for breaks or corrosion and if you can get hold of a injector tester that can make the testing alot easier for injection, simply unclip the injector wire connector and test for a voltage signal with the tester awesome tool to have! I used to have one but I leant it to a friend and never seen it again! good luck with the car mate
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[Hex]

Thing is if its already only firing on only 3 cylinders the "damage" will be done. So for a quick and dirty way of checking and for what I see as minimal risk, I'd do my first suggestion.

However when I read that you had replaced a HT lead I assumed that you ment leadS. As you never get a new set and see what happens.

As they say, only a fool assumes.
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The BCF's very own Party boy! Though he's getting old and feeling it!
Monkey hanger, Born and bred
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