23 replies to this topic

[RalphyBMW]

CS2 VXT

These could be totally unrelated.

If I change from 3rd to 4th at high revs and apply WOT, my VXT seems to hesitate momentarily, this is typically around 4k rpm I believe. It isn't really a problem but I don't believe it should do this.

Otherwise the car is absolutely fine to drive, nothing strange happening.

Over the next few days I am going to change the plugs and air filter, more in the interests of ruling them out, and despite the FSH I am not certain when these were last changed.

Beyond that I am thinking either;

• AMM - Turbo hose (replace with Pro Alloy?)
• Intercooler - inlet manifold hose (replace with silicon? If so where can I get this
• AMM itself - is it worth replacing with the 80mm Astra VXR item? Wouldn't a faulty AMM show other symptoms?

Any suggestions as to whether or not this is a sensible course of action, or anything that I might not have considered?

Possibly related, possibly not, the car very kindly illuminated the CEL for my birthday, and showed the code P1106. From what I can gather, this code seems to relate to the MAP sensor. I have read several posts about it but nothing seems to close itself off.

Having reset the code, I took the car out for a good drive, got it nicely warmed up and tried to check power delivery in each of the gears, it was in doing this that I identified the hesitation in 4th, though 1-3 all seem fine.

Any suggestions gratefully received!

[VXT Tim]

What fuel is in the car and how old is it? Edit - the fuel not the car

Edited by VXT Tim, 10 September 2012 - 05:55 PM.

[RalphyBMW]

Vpower, 2 weeks ish

[VXT Tim]

Hmmm not that then.

[Bumblebee]

Could it be the boost solenoid?

[Bumblebee]

Come to think of it when I was at stage 2 I had this problem took it to MMG to go stage 3 and it's now all ok He changed the amm to the 80mm amm so maybe it's your amm? If it was me I'd change it to the 80mm amm

Edited by Aimy, 10 September 2012 - 06:34 PM.

[Bumblebee]

If you turn the car off for a few mins and back on is all ok again?

[RalphyBMW]

It is all ok 99.5% of the time, just this brief hesitation in 4th when nailing it, after the hesitation its fine. Thing that potentially puts me off the 80mm AMM is that I think it would need a remap, more £££!

[Bumblebee]

When I had this problem I went to stage 3 and the fault was cured so Id imagine it's either coil pack,amm or the 2 solinoids as these was replaced on mine at stage 3,sorry cant help anymore can only relate to my experience re fault code

Edited by Aimy, 10 September 2012 - 07:29 PM.

[RalphyBMW]

Ah, yours had the same code? Did it drive differently when the CEL came on? I don't think any of those parts are overly expensive but would be useful to be able to narrow it down more. Thanks,

Edited by RalphyBMW, 10 September 2012 - 07:54 PM.

[MrSimba]

Boost issue very much sounds like your rubber pipe to top hat collapsing under high load, re-enforce it with a few well placed jubilee clips and see if that solves it, certainly has on a few other VXT's with the stock OE hose P1106 is the MAP sensor throwing a hissy fit I think worth a search on here to look into

[RalphyBMW]

Thanks, that was actually exactly what Mangham54 suggested when I saw him yesterday, what put me off slightly was that there doesn't seem to be much demand for uprated intercooler to inlet manifold pipes. So presumably get some jubilee clips and fit them every 8" or so, and see if that solves the hesitation? I did look up P1106, spent ages looking for a solution but while there were various suggestions of things to try, there seemed to be little conclusive. Do you think the two issues could be related?

[MrSimba]

I'd fit them probably every 5" or so especially on the bend round to the TB that tends to be where it collapses.

[RalphyBMW]

Cheers, will try to get hold of some and see what happens

[siztenboots]

its either bad earth , or the actuator or wastegate sticking / actuator solenoid+small-hoses 1. contact cleaner on the plug at the top of the intercooler, then inspect wiring loom back to the fuel injectors and the earth 2. the actuator rod should move freely , check it can open the wastegate level without hitting the V-band clamp for the exhaust downpipe 3. the boost control solenoid, inspect wiring, inspect rubber hoses for splits what the engine is seeing is more boost pressure than requested

[RalphyBMW]

Brilliant, thanks. Intercooler plug, access through drivers arch? How do I get to the actuator rod, undertray off and from below? Boost control solenoid, this is on the inlet manifold near the TB? Access from above? Sorry for the perhaps less intelligent questions, I haven't had a turbocharged car before and am just getting to grips with the mid engined layout, how you access different parts, etc.

[siztenboots]

actuator get to it from above, remove clip from intake pipe from turbo and move , important cover the turbo (from any stray objects to fall in) , then remove upper heatshield

[RalphyBMW]

Brilliant, thank you

[siztenboots]

prop the boot lid with something much longer (I use an umbrella) so you get full access

[RalphyBMW]

Sounds like a plan, thanks for that