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Discussion Starter #1
Hi all,

I have a 1998 laguna 2.0 8v RT Estate which i bought recently.

It has a problem with the engine where it idles quite low and as a result makes the driver shake lol. Also when you drive it its not too bad but you can hear/feel it misfiring, but especially in 4th and fifth where the engine feels like its struggling to run properly.

I know the engine was pressure washed when i picked it up and as a result thought it could be water in the coils somewhere, ive cleaned the wells out where the leads plug in but was planning to take them off to have a further look.

Does anyone know if this is ok to do? do i need to dissconnect the battery or anything? Its had new plugs and leads so i know it cant be them.

It has twin coils fitted that runs the four cylinders.

Hope someone can help as im going through fuel like theres no tommorow. lol

Thanks!
 

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Hi Johnboy - looks like you've learnt your lesson - never ever take a high pressure hose to an engine - it forces water into areas that were never designed to get wet. My mate done it once on a Fiat and ended up spending over a £1000 to have various electronics replaced. I assume you have the old fashioned ignition system consisting of one/two coils with HT leads - if that's the case you can disconnect and dry things out - a hairdryer is a good method of chasing the moisture. There is also a possibility you may have damaged the coil/s but time will tell. Also remember WD40 is an excellent for dewatering as that is its prime function.

P.S. My local car washers and pre-MOT washing station no longer will clean engines without written consent after someone tried to sue him.:)
 

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Discussion Starter #3
Hi,

Well the engine was cleaned before i bought it, i never would have done that as i used to be a valeter and know what damage it can do!

So are the coils ok to just unbolt without the battery being disconnected?

Can they be opened up?

Also if i spray wd40 around the coils will it still run ok?

Thanks
 

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For safety reason it is recommended to disconnect the battery first but remember you are likely to loose the radio code - otherwise it should be Ok unless you have a pacemaker. The coils are sealed and are non servicable. Dry everything off as much as possible give it a spray of WD40 and see what happens -after that you may need to replace the HT leads and/or the coil/s. Also check the output of the alternator in case it has become water damaged.:)
 

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i had the same sort of trouble with mine after i bought it.took it back and they said "it was water in the coils,probably from when we valeted it"i also took out the tdc sensor that morning and cleaned it(starting probs).not been nowhere near as bad as it was,wheather it was the coils or the tdc sensor who knows
 

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Discussion Starter #6
Ive just been out and cleaned up the coils, but still the same. Maybe the water has damaged one or even both. Havent tried the tdc yet but think its probably gonna be the coils anyhow.
 

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Hi Johnboy - have a real close look at the coils and see if you see any fine cracks or signs of arcing. You could try taking a lead off one at a time and see which coil is at fault - but it is recommended that both coils be replaced at the same time. It would also be wise to check if the TDC sensor is clean as muck and dirt could have been forced around it.:)
 

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Discussion Starter #8 (Edited)
Hi all,

Im lost I still have no idea why my car is missfiring!

I have checked the following:

Coils (look new) replaced
Spark plugs (these are new) replaced
HT Leads (Look new) replaced
EGR Valve (bit dirty but cleaned)
Injectors swapped
Compression test - ok
Leak off test - ok
Read ECU - NO faults


I am beginning to run out of ideas of whats wrong, even my local garage are puzzled.

I would be grateful for any ideas as i am begining to think ive wasted my money on this car.

Thanks
 

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Ok. I had this problem. First things first is don't take anything at face value. Invest in a set of four ignition testers.(About £8.00 from Halfords). These clip on between the spark plug and lead. When started, they flash. The flash should be consistent and blend into a blur when the engine is revved. I suspect that one of your coil banks is fried and they will just suddenly go with no external indication. Don't forget, they supply two cylinders so this will be quite pronounced and it will feel like the engine's got no umph
 

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Mmmmmnnnn tricky one. I know this sounds stupid but are you sure each lead is matched up to its correct plug. the reason I say this is that they would all spark correctly but you wouldn't be able to tell the order. Its quite possible that who ever sprayed inside of the engine bay may well have pulled the leads off and put them back wrongly.

Lee
 

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Discussion Starter #13
Hi,

Yes confirmed by a renualt technician that they are connected correctly i.e left coil plugs into cylinders 2 & 3 right coil plugs into cylinders 1 & 4.
 

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Discussion Starter #14
By the way. the car was plugged into diagnostics at renault and still showed no faults plus no engine managment light on either!!

What the hells wrong wiv it? :crazy:
 

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Hi Johnboy - as the problem started after the electronics got wet it would appear that there is a breakdown in some of the insulation. It may be worth trying a couple of second hand coils as coils can be very fickle and start to breakdown intermittently. A friend of mine got his old Laguna power-washed under the bonnet and a few weeks later had misfiring problems. Fitted two new coils and hey presto no more bother.:)
I have also heard of cars being put on a diagnostic machine and not detecting a TDC sensor fault.
 

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After running what colour are the plugs and are all the same colour. It may also be worth checking the O2 sensor in the exhaust.:)
 

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Discussion Starter #18
If you mean the colour of the tip of the plug then a couple of them are black, probably where its been misfiring, but they were new plugs.

How do i check an o2 sensor? also where is it located? would this cause a misfire?

thanks
 

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I think he means the Lambda sensor. Its screwed into the cat or just above the cat. If the cat is deteriorating then chances are the sensor is shot too. About 60 quid to replace I believe
 
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