Need help please

[andyc58]

Does anyone know what this is. Got misfire on cylinder 3. New plugs. Coil pack and leads. Still there. Unplugged Injector and engine nearly stalls so I assume injector is OK. But found this. Not sure this would cause a misfire but it needs fixing. Any help would be good.this is the only fault that keeps returning

 

[andyc58]

ANYBODY

 

[TheBandit]

Looks like a one way valve, maybe PCV/vacuum system? If faulty it would cause a high idle but not specifically a cylinder misfire

Have you tried moving the cylinder 3 injector to say cylinder one and see if the misfire moves with it? If it's not the injectors you may be chasing electrical gremlins

From another thread on the site:

Re: Missfire on cylinder 3, new plugs, leads, coil and injector is working. Plug is b

Ok think i have found the problem this evening . As the compression ratio is ok, the spark plugs are fine the coil is fine and the leads are ok. It leaves me to believe its fueling.

As only one spark plug is showing signs of problematic combustion, and there are no sensor fault codes coming up in the ECU. It leads me to believe its cylinder specific fueling problem, not caused by over fueling due to trying to compensate for bad sensor reading as that would effect all cylinders.

So this leaves the injector, and the ECU. I had the injector out before to see if it was spraying and it was, but by how much compared to others i have no idea.

So from this I have swopped the injector from the problem cylinder3 to cylinder1 that was working fine. If the incomplete combustion moves cylinder its the injector thats the problem if the problem remains at cylinder3 its the ECU sending out to long a pulse width.

Turns out after ten mins of running problem of bad idle still present. check the spark plugs again and the cylinder3 plug is starting to clean up and the cylinder1 plug is starting to carbon up. Therefor i believe the problem is the injector is leaking or over-fueling for what ever reason. so placed a order with renault for a new one . will post if it solves the problem . maybe useful someone in the future.

 

[Robbie Corbett]

I bet its an injector or the primary lambda.

 

[andyc58]

I bet its an injector or the primary lambda.

Gettingbto injector was a pain. All I done was unplugged the injector and engine nearly stalled. Will take fuel rail off tomo

 

[Yarp]

Gettingbto injector was a pain. All I done was unplugged the injector and engine nearly stalled. Will take fuel rail off tomo

That’s the easiest way to test. Swap them round and if the misfire moves cylinder you have your problem.

The injector could still be functioning, just not well enough to run smoothly.

 

[andyc58]

Looks like a one way valve, maybe PCV/vacuum system? If faulty it would cause a high idle but not specifically a cylinder misfire

Have you tried moving the cylinder 3 injector to say cylinder one and see if the misfire moves with it? If it's not the injectors you may be chasing electrical gremlins

From another thread on the site:

I do have low idle. Jerking under pulling away. When at 60mph car is fine

 

[Robbie Corbett]

My car got progressively richer as the injector failed. Took a while for it to start missfiring.

Injectors are pretty easy to change! Just take the rail cover off and it's all right there.

 

[andyc58]

Looks like a one way valve, maybe PCV/vacuum system? If faulty it would cause a high idle but not specifically a cylinder misfire

Have you tried moving the cylinder 3 injector to say cylinder one and see if the misfire moves with it? If it's not the injectors you may be chasing electrical gremlins

From another thread on the site:

 

[andyc58]

Could I get away with this as a fix

 

[Yarp]

Could I get away with this as a fix

That’s not your problem. That leaking would have minimal impact on anything other than a higher idle.

I use a small vacuum leak to moderate the idle on my turbo’d 182. All the boost pipework makes it idle too low and cut out from time to time and the leak cures it.

 

[andyc58]

That’s not your problem. That leaking would have minimal impact on anything other than a higher idle.

I use a small vacuum leak to moderate the idle on my turbo’d 182. All the boost pipework makes it idle too low and cut out from time to time and the leak cures it.

I would still like to fix this issue as well. Just wondered if that part would work

 

[Robbie Corbett]

I can't see whats up with your one way valve? Is it cracked?

Edit. Ahh the barb has snapped off.

 

[Robbie Corbett]

Vacuum Check Valve Air Pump Valve Car Accessories for A4 TT 0 V4N9 | eBay

For 2001-2006 TT BASE CONVERTIBLE 2-DOOR. For 2000-2006 TT BASE COUPE 2-DOOR. For 2006-2006 TT CLASSIC EDITION CONVERTIBLE 2-DOOR. For 2006-2006 TT CLASSIC EDITION COUPE 2-DOOR. For 2001-2001 A4 CONFORT WAGON 4-DOOR.

www.ebay.co.uk

Check barb sizes, autodoc also lists various Febi ones.

 

[andyc58]

Update. It was injector. Only gone and dropped a bolt for the fuel rail. Does anyone know the bolt size

 

[Gus]

probably M6 with a length of 20.