Turbo Stutter/ misfire - how to check ICSV

[chrisg]

Evening All !

Thought I'd share my latest issue and the eventual solution. So, prior to resting the car up for winter in November, when cold (cleared when warm it had a difficult tickover and noticeable stutter/ hesistation under boost. After replacing the belts & rollers over the winter, it was even worse so I took the plunge and removed the AFM and TPS - both were 'refurbished'/ rebuilt as per Clarks & Arnnworx respectively. Despite all the work it was still running rough even when warm.

So, replaced the spark plugs, drained the tank, cleaned out the in-tank filter and replaced the inline filter. still no change.....

Talking to Scott the other day got me thinking about things and I started to think about potential faults linked to the air/fuelling.

Anyhow, after checking for boost leaks with carb cleaner and soapy water, I thought how can I test to see if the ICSV is stuck or creating issues.

Thinking it through, the ISCV (in theory) is only activated at tickover by the microswitch in the TPS.

So, I blanked off the feed to the ISCV using a brake hose clamp at the TPS/ Hardpipe end where the pipe emerges from under the inlet manifold. = rough as at tickover BUT, running like a dream at full boost. [BTW you have to run without the air filter to get the clamp in].

Since putting it all back to normal spec, the ISCV is working fine and shes running like a dream, just need to make the sure the ISCV is cleared out and not sticking/ leaking.

Thought I'd share this little trick for all your boost boys,

Chris


So,

 

[Paul 290T]

Thanks Chris. I bet that helps a few of us out in the years to come.

 

[944Scott]

Nice to meet you the other day.

 

[chrisg]

Good to meet you too Scott, and thanks for the inspiration/ ability to talk through the issue - I spent the rest of the day at the Pharmacy thinking about how to fix the air/fuelling issue - and it worked !