Anyone experienced similar (or have any thoughts)...?

Post by **mbelle** » Wed Jan 21, 2009 6:37 pm

I'm getting really pi$$ed off with 2 issues with my car at present (which aren't related)...

1. Hesitation @ 3K under light throttle. Under full throttle, it's fine. Crack sensor has been replaced, MAF checked and no fault codes show on VAG-COM. N75 valve has also been replaced (which is when this issue started) and the issue does not exist if I disconnect it.
This makes for very difficult crusing as 80mph=3K - any faster I'm breaking the law, <70mph I'll never get to my destinations on time!
Not such a major issue though as I have a workaround i.e. leave N75 disconnected.

2. Vibration between 70-~100mph. Builds up from 70, worst at about 80 and starts getting better further up. Wheels have balanced and aligned.
Any thoughts?
This also makes for very difficult crusing, for which I have no workaround for...

Thoughts/advice appreciated.

Marcus

Post by **p.binks** » Wed Jan 21, 2009 7:15 pm

1,boost leak,n75 no good,maf needs clean or replacing.

2,bent wheel or possible tyre problem,wheel bearing?

Post by **jimbo1234567** » Wed Jan 21, 2009 11:53 pm

marcus a bad maf will not show up on vagcom when you do a scan. the only way to check it is to do some logs with the laptop. if its the same maf as when you got the car then i would say change it as a matter of course as they cause so much trouble. in the mean time disconnect the plug from the maf, this will bring up the abs and engine management light up on the dash and see how it runs. when you plug it back in the lights will go off. the car will just run a bit richer. best change the maf before it takes the egt sensors and lambdas with it. anyway where were you on monday????????

Post by **jimbo1234567** » Wed Jan 21, 2009 11:54 pm

change the wheels front to back.

Post by **Contigo** » Thu Jan 22, 2009 12:23 am

2. Exactly as Jimbo said. Got a puncture recently and I had vibration in wheel at 80 but not at 70 so I moved the non bent rear wheels to front and vice versa and now it's smooth as a baby bum. No vibration at all, drives and handles as it should do.

With regard to the first point I'd agree that the N75 could be forked still or could be exposing a boost leak of some description.

Post by **mbelle** » Thu Jan 22, 2009 8:15 pm

OK - next course of action then, I'll get some logs...
I have actually disconnected the MAF already (forgot to mention that); plus I changed the MAF ~1 year ago though, so I'm not entirely convinced it's that - not saying it won't be though...!?
Personally, I think it is the N75; as mentioned, I changed it, along with a new O/S cooler, xmas Eve and since then, have experienced this hesitation (although not immediately??)

I actually thought of bent wheels on the m'way this morning, so I'll get them swapped around and see what happens.

Thanks lads.

P.S. Sorry Jimbo, I was at a customer in Central London on Monday. Were you there in yours? How's is your running now??

Post by **Contigo** » Thu Jan 22, 2009 8:39 pm

mbelle don't forget you do get this on the B5's at this rev range when backing off the accelerator at around those rev as the boost comes off. I've noticed it a few times.

I had it more pronounced a year and a halg ago and it turned out I had a boost leak and MAF changed, been fine since (touch wood)

Post by **mbelle** » Fri Jan 23, 2009 12:28 pm

Contigo wrote:mbelle don't forget you do get this on the B5's at this rev range when backing off the accelerator at around those rev as the boost comes off. I've noticed it a few times.

I had it more pronounced a year and a halg ago and it turned out I had a boost leak and MAF changed, been fine since (touch wood)

Yeah, I'm OK with that but this feels very different.
The reason I think it's the N75 is because it feels like something is taking away what it believes to be too much boost just before 3K before it starts hesitating @ 3K.

Thing is, it's only under light(ish) throttle - full throttle it's fine...

M

Post by **Blue_Thunder** » Fri Jan 23, 2009 1:40 pm

mbelle wrote:Thing is, it's only under light(ish) throttle - full throttle it's fine...

M

Then you know what to do

Agree with what's been said above. Sounds like a boost leak to me. I had something similar when my one-way valves were shot. Got Grizz to replace them and the problem went away.

Post by **mbelle** » Fri Jan 23, 2009 7:31 pm

Issue 2 resolved - bent wheel!
Third one in a year - can't wait for the next one...

Post by **andream88** » Fri Jan 23, 2009 11:26 pm

Hard or Soft wheels?

Post by **mbelle** » Sat Jan 24, 2009 1:15 pm

Hard - all of them!

Post by **Contigo** » Sat Jan 24, 2009 9:16 pm

Hard but not so hard. Audi want shooting for that design and then the redesign!!!

Post by **carlosfandango** » Tue Jan 27, 2009 2:38 pm

Only 3 Wheels in a year your not driving hard enough lol

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Anyone experienced similar (or have any thoughts)...?

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