C32 strange misfire

[Gaz74]

Hi all,

My C32 has developed a misfire/rough running in the last few days and it's a bit of a puzzler, as I put the car on to Star at my local dealer (a friend is a tech there) and it showed no misfires at all. I was kind of hoping that it would, so I'd have somewhere to aim for, but it came back all clear. As you drive the car, you put your foot down to accelerate and the car is really holding back. I can only liken it to driving an old car with the choke still fully on, as it really coughs as you try to give it some gas. Also, as it's cruising at speed on the local bypass and you're just feathering the pedal to hold speed, it suddenly cuts out (not stalling) but as if you've taken your foot off the pedal but a bit more abruptly (if that makes sense). You then have to push the pedal a bit further and it does nothing for a second or so and then it springs back into life.

I'm now possibly thinking it might be a fuelling issue rather than ignition, based on the Star report. Any of you good people got any ideas on this?

Thanks

 

[martyz]

Sounds like a MAF issue.

 

[Neil Mackay]

Sounds like a MAF issue.

No MAFs on a C32 they have MAP sensors

 

[BlackC55]

Check the fuel pressure firstly.

Any visable air leaks?

 

[Gaz74]

My friend is going to check the fuel pressure on Monday, so we will see how that occurs. Without wanting to sound dumb, where would be best to check for air leaks? By that, I mean location-wise.

Thanks for the replies so far, much appreciated

 

[driftyste]

Cam or crank position sensor would b my guess

 

[Neil Mackay]

Not the charge cooler pump suppose!?

 

[Gaz74]

Wouldn't a duff sensor be picked up by the Star?? And the pump was swapped for a Johnson a few months ago, so I'd be surprised if it's failing. Also, it's misfiring when the car's parked, so the charger isn't under load. I'm thinking it could be more mechanical than electronic.

 

[BlackC55]

If it's missing then the live data WILL pick that up.

Air leaks can be from anywhere on the intake side.

 

[Gaz74]

Just thought I'd update... After testing the fuel pressure, which was fine, I spent Sunday having a root around the back end of the engine where I discovered a split breather hose. It's runs from the drivers side breather cover to a connector under the throttle body and this evening I swapped it for a new one. It required the inlet manifold to be removed, along with the throttle body, but was fairly straightforward to do. Took the car for a blast and it's running fine, all sorted!
All in, it cost me just over £10 in parts which makes a rare change on a C32!! lol

And thanks again to all who took the time to comment and help me.

 

[merc85]

Awesome news an a nice cheap easy fix, thanks for posting what the cure was, as it may well help other peeps in the future