Weird surging at cruize throttle.

[Percy]

So I went for a blat in teh GTB today, and noticed it surges sometimes when cruising at 100k, cos I would never go over 100k cos thats like illegal and stuff...

Anyway it almost feels like the aircon compressor coming on and off, but far more noticeable, yet happens when the aircon is off or on.

I havent had time to clean out teh BBOD yet, so would it be something in there?

Or a leaky hose somewhere?

Edited March 8, 2015 by Percy

[Rosssub]

Most likely the O2 sensor, maybe AFM.

[Percy]

 Rosssub said:

Most likely the O2 sensor, maybe AFM.

Dammit!

Why couldn't it be something cheap...

Cheers Rosssub!

[Joker]

could be George

[Percy]

 Joker said:

could be George

Curious George?

[A_J_T]

Do you have a boost gauge and when the power surges does the boost also surge/flutter slightly?

Sometimes when cruising in mine id hit a slight incline keeping the same throttle position load would come on slightly and boost would build a little and drop and so on, it would feel somewhat like you have described. just the wastgate having a little trouble figuring out what to do with itself. if i applied a little more throttle it would sort itself out but the TT wastgate always seemed a little touchy on primary when cruising. Ross is probably right but that's just my two cents

[Percy]

 A_J_T said:

Do you have a boost gauge and when the power surges does the boost also surge/flutter slightly?

Sometimes when cruising in mine id hit a slight incline keeping the same throttle position load would come on slightly and boost would build a little and drop and so on, it would feel somewhat like you have described. just the wastgate having a little trouble figuring out what to do with itself. if i applied a little more throttle it would sort itself out but the TT wastgate always seemed a little touchy on primary when cruising. Ross is probably right but that's just my two cents

No boost gauge yet, that does sound and feel like what its doing, speed changes about 2-3kph each time.

Seems to do it less at 110+, possibly cos the throttle is open more, or its less noticeable.

[Joker]

OG CS'er named leaking BOV noise as George

sounds like someone blowing across the top of a milk bottle

[A_J_T]

Has this suddenly just started happening, or has it always been there? I noticed you did the Silicone TMIC pipes not long ago so this could have had some effect on it I guess. Mine has always done it before and after breathing mods. Do you have any CEL popping up at all? If it was an o2 sensor it would usually throw out a CEL

[Percy]

 Joker said:

OG CS'er named leaking BOV noise as George

sounds like someone blowing across the top of a milk bottle

Ahhh, didn't notice any noise like that, might have to turn the Doof Doof down to hear it.

I havn't had the car long enough to know if it was always there, and the cracked TMIC factory pipe may have been masking it or causing other weirdness which is now gone with the new silicone pipes.

I'll try cleaning everything in sight, and the bits out of sight in the BBOD etc, including teh MAF sensor if possible.

Might need some more evil cleaning chemicals...