not having much luck with this one.

[seabass859]

So after a buying a 172 2 weeks ago I've had a dodgy idle issue, a immobiliser issue, (now resolved)and today she starts misfiring and the eml flashes. I have used my obd2 but no code appeared to be stored (its probably the torque app I use not dectecting) any ideas where to start??

 

[not normal dan]

Sounds like an injector issue from experience, do you have access to a multimeter?

 

[seabass859]

Sounds like an injector issue from experience, do you have access to a multimeter?

Yes mate

 

[not normal dan]

A good tell tail sign if you don't have a multimeter is to remove the spark plugs, which ever one is black/dirty is good sign that the injector on that cylinder has failed.

The eml light flashes when there is a chance of damage being caused to the catalyst.

You can test the resistance across the coil on the injectors, it should be 14.5 ohms. If it's broke it'll be lower or at worst case open circuit

 

[seabass859]

I'll give that a go mate

 

[seabass859]

So I've finally got her to spit out a fault code p0314 cylinder misfire, unspecified cylinder.
Would you still assume the injector is the culprit?

 

[not normal dan]

Tbh that doesn't mean a lot it's just telling you it has a misfire, doesn't really narrow it down.

Have you tried pulling ht leads off the coil pack 1 at a time whilst running to see if that has an effect? The 1*2''s run a wasted spark system so the coil pack has 2 circuits in theory (example cylinder 1 and 3 and then cylinder 2 and 4 ) so if it fails it tends to fail on one side or the other creating a multiple misfire. So if pulling the lead off either 1 and 3 has no effect or pulling the lead off 2 and 4 has no effect I would be saying coil. But if it's only on 1 of 4 cylinders I would be looking towards ht leads or even a duff spark plug.

I would certainly resistance test the injectors for piece of mind though but if there completely fucked i.e open circuit they tend to bring up there own code. Yours certainly sounds ignition related.

 

[seabass859]

I'll be trying that in the morning. Cheers mate the help is much appreciated

 

[seabass859]

Would you not get a shock when you pull the leads off ??

 

[not normal dan]

Would you not get a shock when you pull the leads off ??

No mate just keep your hands clear of the coil output chap

 

[seabass859]

I bought some new ht leads and fitted them, I've also checked the plugs and have 3 old ngk and 1 Bosch so after a little inspection have decided it to be best knowing the coil pack is new I would order a full set of ngk's and have a complete new ignition system put it all back together (with old plugs as none in stock atm) and she's running sweet! For now....

il il be fitting the new plugs on Monday and see how we go