[Taslaw]

Hi all; My 156 2.0 jts (53 plate) started badly misfiring today, limped home making a terrible noise and shuddering heavily. Put the diag on and got the following codes: PO300, PO301, PO302, PO303. This indicated misfiring of the cylinders 1 through to 3. I noticed that the cat was glowing red hot, as soon as I could inspect the car.
I had the plugs replaced 2 months ago; is this a symtom that they were the wrong ones the garage fitted, or are the coils on the way out? Would 3 coils go at the same time? Is there anything else that may be causing it i.e. MAF etc? There were no other fault codes registered. I left it for a couple of hours and it is still misfiring.
Any advice would be appreciated.

 

[biffa]

Coil pack on number 3 is a common failiure... Change the coil pack and dont drive the car as the reason the cat is glowing is because unburnt fuel is combusting in the cat and may of already wrecked it...

 

[mini jts]

Hi all; My 156 2.0 jts (53 plate) started badly misfiring today, limped home making a terrible noise and shuddering heavily. Put the diag on and got the following codes: PO300, PO301, PO302, PO303. This indicated misfiring of the cylinders 1 through to 3. I noticed that the cat was glowing red hot, as soon as I could inspect the car.
I had the plugs replaced 2 months ago; is this a symtom that they were the wrong ones the garage fitted, or are the coils on the way out? Would 3 coils go at the same time? Is there anything else that may be causing it i.e. MAF etc? There were no other fault codes registered. I left it for a couple of hours and it is still misfiring.
Any advice would be appreciated.

i would check and see if any oil has leaked around spark plugs as you have multiple misfire and at same time check plugs and condition of coil packs GOOD LUCK......

 

[Taslaw]

Thanks Biffa; how will inknow if the cat's buggered?

 

[Taslaw]

If the coil pack is faulty, will it have any obvious signs, or will replacement be the only true indicator ?

 

[mini jts]

If the coil pack is faulty, will it have any obvious signs, or will replacement be the only true indicator ?

I had one go on number 3 and a melted hole on the side of the coil pack had a spare so sorted and only showed error po303 because you have 3 cylinder errors i would check each coil pack and plugs if you had one error or two i would swap packs arounds to see if error moved cylinders then you would know if coil pack is faulty or not but would check for oil around spark plugs does happen common fault..................

 

[Taslaw]

Thanks mini, much appreciated. Will play around with it tomorrow.

 

[biffa]

Thanks Biffa; how will inknow if the cat's buggered?

mild to sever lack of performance...poor lambda readings...

 

[mini jts]

Any luck on sorting the problem.........

 

[Taslaw]

Keith; the coil packs are all ok , however the spark plugs are very fouled up with soot. This may suggest a air/fuel mix problem. I had the air filter changed around 2000 miles ago and there are no errors reported on the Maf; do you know anything else that may be causing the misfire?

 

[mini jts]

You said you had the spark plugs changed are you happy the correct ones were used to replace the old ones,replace your plugs and see how your car runs if the problem is still there then i would get someone to take a look sorry cant be more of a help.......

 

[biffa]

How did you prove the coil packs, often they fail with no external evidence.

 

[Taslaw]

Tested the coils for resistance using multimeter.

 

[Taslaw]

The plugs that were replaced in June were: Ngk's bkr6ekpa. I was informed (by local garage) that they were the right ones for a 2.0 jts, they were £70, hope this info was not duff, and this has been the problem...

 

[mini jts]

The plugs that were replaced in June were: Ngk's bkr6ekpa. I was informed (by local garage) that they were the right ones for a 2.0 jts, they were £70, hope this info was not duff, and this has been the problem...

They are it seems the right plugs but would replace them and see if that sorts the problem pos dodgy plugs maybe but not sure on that one.Will say though they did over charge you on the plugs link below to see how much by...........

JTS spark plug set for Alfa Romeo 156 parts and spares

 

[steve7]

my codes were simaler, turned out to be a fault on the wiring loom.

ofcourse I only found that out after replacing the coilpack , sparkplugs, and money.

 

[Rockhopper]

I'd put money on it not being the plugs.

 

[Taslaw]

Keith, thanks for the link, I have ordered some new ones. Fingers crossed...
Steve7; how did you find out eventually that the wiring loom was the problem for you?.

 

[steve7]

I didnt think it was the sparkplugs either but your friendly mechanic says something along the lines of..
"Ive seen this problem with alfas not having the right plugs in....... blah blah "

In the end I took it to an ex franchise in Carlisle, took them about an hour to work out what it was.
I think it will need some one with a computer and multimeter ..

good luck

 

[finny05]

Have just bought a 2.0 jts with suspected head gasket except me and Big Ginge think its a collapsed cat,but what we did come across was a split in the air intake after the maf, near the end of the rubber concertinia,this would have seriously affected air ,fuel mix, you outa check yours make sure no air is getting in after the maf.Will keep you posted on ours. Big Ginge is trying to get a plug in to read the fault codes that are there.