funkyjutel

Those of you who know me, will know that I have had an on-going saga to get my Mk1 Octy running right.

Sadly no-one appears to be able to diagnose the problem.

In recent months I have changed just about every component on the car to no avail and spent a tidy sum.

Symptoms are as follows:

Low power, poor take off in low gears, with super lumpy running.

High gears, boost being backed off consistently, surging, in-consistent boost, lack of boost on demand etc etc etc etc etc etc.

I have taken the car to several tuners, none of whom appears to be able to solve the problem.

I have been advised to change the following:

Air mass meter - Changed
Air mass sensor - changed
Temp sensor engine block - Changed
Knock sensors - One changed, next one being done next week
Full service, new plugs - Done

and yet.................... no good at all, if anything the car seems to be worse.

10k ago I had a full bottom end rebuild as well. So I have spent a s**t load of money on the car and still it performs like a sack of s**te.

The sad thing is that I really like this car. I recently has a genuine WRC rear wing fitted, front end respray inc Milotec front grille and all my wheels refurbed and colour coded.

The irony is that it looks a million dollars but performs like a mini metro.

I hope you can understand my frustration and yet in the land of tuning my car remains a mystery no-one can solve. Believe you me I've heard every theory under the sun as to what's wrong with it.

If anyone has any PRACTICAL suggestions I'm all ears (unless I've heard it before that is)

My thanks must go to Des for putting up with my constant moaning and his support. He has been the only person willing to try and help me solve this.

I've kind of run out of ideas. So I feel destined to drive a problem car for good now until I decide to sell it, whenever that might be or if.

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Funky Fathering Is Where It's At

duke of hazzard

boost reg valve? (N75?) good luck with it.

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Mods, Colour coded grille, DVD player, Fancy headlights, Whooshy thing, One of them brillo pad filters where the car sucks air in, and windows upgrade on the cpu from ME to Vista!

auroan

Could be a boost leak ? Have you checked all the pipes and connections ?

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'96 AUDI A4 AVANT 2.6 V6 with a few modifications

duke of hazzard

yeah, check all of the boost pipes and vaccum pipes. could be a split in one or ones come undone etc. (im sure you've checked these but ya never know)
my old focus had a vaccum leak once an that ran like a sack of the brown stuff and displayed exactly the same symptoms.

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Mods, Colour coded grille, DVD player, Fancy headlights, Whooshy thing, One of them brillo pad filters where the car sucks air in, and windows upgrade on the cpu from ME to Vista!

f1btn

I would have the car logged with vag-com and then get someone who knows what there looking at to check all the parameters,it could be the rear lambda probe if its not throwing any fault codes or throttle body problems or dump valve if it is! Really need to get the car looked at by a pro there are quite a few issues with the 20v engines and im sure most would have been covered on here!

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funkyjutel

The problem is that I have had the car looked at by many pro's or at least a high proportion of those who are "Leading tuners"

The car shows no fault codes at all. Dump valve was changed back to standard, infact it's had 2 dump valves in a year and an N75 valve about 9 months ago. The problem seems to be that there are 2 million suggestions. So far I guess out of the 2 million I've tried about 1.5 million of them and none have worked and it's costing me a small fortune.

I've also got to admit that very few people want to spend any real time trying to find the fault. Most just seem to have a theory, put the part on and say come back if it doesn't work. It seems problem cars don't make money and after a few times they think you're making it up if their fix doesn't.

Weirdest thing is that often it makes the car better for about a day or so by changing something then after 24 hours, hey presto, no change and back to what it was before.

Oh and before I forget I replaced all the coil packs 3 months ago

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Funky Fathering Is Where It's At

duke of hazzard

...and the vaccum&boost pipes are all in good order?

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Mods, Colour coded grille, DVD player, Fancy headlights, Whooshy thing, One of them brillo pad filters where the car sucks air in, and windows upgrade on the cpu from ME to Vista!

EddyH

Have you got any vagcom logs of boost, timing and lambda? This will help see where the power is going. e.g. is it making boost but timing is being backed off? If it is not making boost is it because it's backing it off or is it simply not able to make the requested boost? Is it getting enough fuel? Has the fuel pump pressure been tested?

BTW is the engine standard or remapped?

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EddyH

Audi S8
Audi A3 2.0 TDI Sport

funkyjutel

Eddy the engine has been remapped. Fuel pressure pump has not been tested. One of the few things that hasn't. For a numpty like me, how is this done. I do have a vagcom log that Des and I did, which seemed to suggest knock. I can send it to you for any suggestions you might have, it's on an exel spreadsheet (pm me an e-mail address if appropriate.

It does some weird things, such as almost no boost at all in low revs, car just moves forward at normal revs. To get it to go you have to rev it and then it comes on boost, strong then off as soon as it comes on which makes it jerk then stop.

At higher revs or at higher speed it will come on boost and then as boost builds, it starts to back the boost off when you want it. It runs very unevenly on idle, almost feels like it wants to stall sometimes.

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Funky Fathering Is Where It's At

funkyjutel

They seem to be. Have all been checked for leaks with that leak detector fluid. No faults or leaks seemingly.

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Funky Fathering Is Where It's At

simonlb

Does the engine rev freely when in neutral and only have this problem when under load? I'm not sure if this will be any help but its possible one of the exhaust silencers or the catalytic convertor may be collapsing internally and causing an increase in back-pressure in the exhaust.

I've seen similar posts on one of the forums I used to browse and the symptoms sound the same. It may be worthwhile having the exhaust/cat checked out.

auroan

Who did the map ? Has it been like this ever since the map or just recently ? I have heard of dodgy re-maps where people spend forever trying to fix a poorly running engine by replacing components... only to find the the orig re-mapp was carp.

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'96 AUDI A4 AVANT 2.6 V6 with a few modifications

funkyjutel

Yes engine does rev freely and is like this underload. Havn't looked at this. ASll I will say is that the exhaust on my car was a very expensive hand built one and cat is a 100cel jetex cat, I would say about 14 months old.

Might be worth checking though. What do I need to look for?

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Funky Fathering Is Where It's At

funkyjutel

Jabba did the remap. They tell me it's fine and another tuner told me the map was fine too.

If anyone wants it I have the recent log that was taken on vagcom. I can send it via e-mail if I get a PM with an e-mail address.

Someone told me it could be knock sensors needed changing. I have changed one. One to do next week.

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Funky Fathering Is Where It's At

f1btn

Please send me the log file to Sales@f1btn.com

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EddyH

I'll PM you with my email addy as seeing the logs will be very useful, particular comparing requested boost and actual.

To check fuel pressure you need to hook up a pressure gauge to the fuel pump (under the circular metal plate under the back seat). You then need to get the engine under load either on the road on a RR. You then need to watch the gauge and check the pressure which should be equal to the FPR rating (3 bar if standard) + boost pressure.

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EddyH

Audi S8
Audi A3 2.0 TDI Sport

simonlb

Good question that. It could be the sound deadening in one of the silencers moving around and blocking one of the silencers up, or you can get the baffles inside the silencer collapsing and doing the same thing. If the exhaust has delevloped a rattle then it would indicate the baffles are loose or collapsing. The only sure-fire way to check would be to take the exhaust off and manually check it.

funkyjutel

On it's way to you

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Funky Fathering Is Where It's At

funkyjutel

Thanks eddy.Will give it a try

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Funky Fathering Is Where It's At

pietch

It could be your throttle position switch! I had a car with this problem, the switch has three positons including wide open, my third position (WOT) was not working causing poor performance and warning light issues.

I also had a failed altitide sensor about a month later!

This was not on an Octy but thought I'd pass comment anyway.