306 s16 Engine Issues

[muffins]

So i'm having a few issues with my s16. I'll try to explain all the symptoms:

-The most obvious is when under anything other than very light acceleration: the engine sounds runs totally rough and lacks power completely. Best description: it sounds kinda like a WRX!! But certainly doesn't drive like one, haha. This running rough doesn't happen when revving in neutral, only when under load.
- The idle is quite rough
- All these problems are intermittent. Sometimes, it runs perfectly. Other times the problems only show up under heavy acceleration. Then sometimes they are really obvious, happening under quite light acceleration.

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Any ideas from the Pug experts would be much appreciated!

[xray]

check hoses for fitting and leaks
check air intake control valve
plugs
leads
rotor cap and button (or whatever ignition set up it is)
air filter
compression
eliminate the simple stuff first.

[Davo81]

it's an S16, it doesn't have a distributor.

sounds like a bung coil to me... problems with the intake manifold wouldn't cause a misfire at idle...

XU9s and XU10s can be very touchy about spark plugs too, so swap them out too....

coils are about $80 a piece from EAI...

[xcmike]

unfortunately my S16 is doing the same thing....

and Davo81 for coils do you mean ignition coils? and what spark plugs do you recommend for the S16? because I might change the plugs as well while changing the faulty coil...

[Davo81]

yeah, ignition coils... be careful though, because a manfunctioning inlet manifold can create a similar problem... if your symptoms are exactly the same as muffins', then I would suggest it's ignition coils...

for spark plugs, I just used NGK-Rs, just get the dude at repco to look it up in the book. others have suggested that Bosch 'plugs work better, but I'm yet to try them...

[atlantean]

I had a similar problem with a newly acquired Xantia - I also thought that it must be plugs,leads,coil , fuel pump - tried a few substitutions - no change - turned out to be the air filter . The engine would idle sort of OK - but wouldn`t pull at speed. Once the air filter was replaced there was a miraculous change!

[blink]

Replace your ignition coils ! Once the hot weather hits us, the fault will become permanent. If you dont replace all 4, i suggest you always keep a spare in the boot, chances are you will need it.

[xcmike]

I pulled the coils out today trying to find a faulty one but they all looked the same (no cracks and such).. one of them felt a bit oily though...

put them back in as I don't have any new ones and then the car felt completely fine for a short drive....

the s16 has a pod filter, how do i clean it? I also want to get rid of this pod and put it back to stock......

anyway I will pick up some coils and thanks for all the advice!

[blink]

With the engine at running temperature, once it starts to mis-fire, pop the hood, remove the coil cover and pull out the first coil, holding the spark plug end close to metal in the engine bay. Do this with the engine running. Repeat with all coils untill you find one that does not arch any sparks. Chuck it in the bin.

At first, it will work well cold and play up once it soaks up heat. Eventually it will just fail completely.


Edit - Hard to tell the faulty one just looking at it, what happens is one of the coils inside goes open circuit i suspect.

[Davo81]

hence why it's probably easier to replace the whole lot... if one's gone, I'd say the others won't be far behind!

[figs]

The "remove one coil at a time with the engine running" trick works well but can be confusing if the problem is intermittent.

If you have a multimeter ($20) you can check the resistance between each of the 3 contacts on the coils. Even without knowing what the resistance is supposed to be you may see one coil is not the same as the others and therefore probably needs replacing.

But firstly, does the engine light on the dash (looks like a "K") stay on for ~5-10 seconds after starting the car? If so you have an error code stored. This would be a good place to start before spending money guessing or getting your hands dirty.

[alan moore]

I had a crook coil in my S2 Mi16. I diagnosed which coil it was by disconnecting one injector lead at a time, the one that made no difference was the cylinder that had the crook coil.

[muffins]

Thanks for everyone's help. Did the coil removal trick, and found there was one dodgy coil!! Replaced it and all good.

Any tips for where you can get cheaper coils from to replace all the others??

[AndS16]

Thanks for everyone's help. Did the coil removal trick, and found there was one dodgy coil!! Replaced it and all good.

Any tips for where you can get cheaper coils from to replace all the others??

I have a new one sitting here. Sell it for $40 plus postage.

Andrew