Only thing that springs too mind is that yours is stg 2 isn't it ???

Mines only a mild tune so probably doesn't ask as much of the fuelling. Mine has been at this point of tuning for years so nothing has changed. Just a sudden drop in performance.

I'll add a little interesting info in a bit. Over me mams a sec and tea is ready lol

Yeh mine are stage 2, I know you say nothing has changed with yours, but you have to remember that age and mileage do cause things to wear / fail.

Also from a log on page 1, your car is still pushing something like 225 - 230bhp, which is well into the stage 2 region of performace.

Yeh mine are stage 2, I know you say nothing has changed with yours, but you have to remember that age and mileage do cause things to wear / fail.

Also from a log on page 1, your car is still pushing something like 225 - 230bhp, which is well into the stage 2 region of performace.

Is it lol, doesn't feel like at the moment.

Here's the latest, I thought I would try some snake oil last night, chucked some STP fuel system cleaner in and guess what, the idle is smoother, the LTFT has dropped a little and the MAF reading on idle has crept up a little too.

Spooky !!!

Still ain't had chance to do some proper logs yet due to alcohol lol

Did a scan this morning and got this

5 Faults Found:

17772 - Cylinder 4 Ignition Circuit

P1364 - 35-10 - Open Circuit - Intermittent

17769 - Cylinder 3 Ignition Circuit

P1361 - 35-10 - Open Circuit - Intermittent

17766 - Cylinder 2 Ignition Circuit

P1358 - 35-10 - Open Circuit - Intermittent

17763 - Cylinder 1 Ignition Circuit

P1355 - 35-10 - Open Circuit - Intermittent

16795 - Secondary Air Injection System

P0411 - 35-10 - Incorrect Flow Detected - Intermittent

It may be down to me charging the laptop yesterday though whilst parked up.

Cleared it for now will see if it returns, it would be nice if it did !!!

Well those never came back so I assume it was a blip when starting the car after charging the laptop.

Some strange twists .....

I thought I would knock up the octane as a trial, did a 3rd gear run after letting settle down in the tank. NOS for mowah powah lol, it says six points on the bottle, don't know if thats mon or ron mind you so,

I already had Tesco 99 in there, so I could be running 105 lol.

It seems to have done something though,

Boost and timing

Timing looks spot on according to what I read, most mappers aim for 3 degrees of pull on an SUL map.

Obviously the boost is an issue, but as I can see there is no relation to the timing pull, unless I'm missing something.

Funny looking at that and knowing how the car feels I can almost see it happening on the graph

So I think I have a boost leak again, did an AFR run too and got this, think it's ok, graph makes the numbers look bigger, but if you look at the figures it ain't out by much.

AFR and timing

Check out the timing pull, it seems completely random.

Get boost sorted and come back and look at timing, if the ecu is controlling it it shouldn't be a problem..... Hopefully

Daves theory time....

Slight boost problem, timing been pulled as number 4 furthest from inlet pipe. Air not reaching number 4 kike it should.

A few things I've read suggest that number 4 suffers generally due to manifold design. Also number 2 is the 'noisiest' cylinder again due to design. I'm seeing a little pull on 2 now and then.

Even read that pull could be happening since fitting the front dogbone bush as the sensors are is microphones which listen for noise.

More later ....

It's going lean at 5500(ish) rpm so at that time it drops the boost off (which it will do by closing the throttle).

Is that why the throttle angle is dipping slightly to 99.6% I take it the lean is the blip on the AFR graph up the top end ??

I got get surging all the way through from around 3.5k

Do you like my graphs, lol

Is that why the throttle angle is dipping slightly to 99.6% I take it the lean is the blip on the AFR graph up the top end ??

I got get surging all the way through from around 3.5k

Do you like my graphs, lol

It's possible thats why block 3 is reading 99.6% but if you look at block 060 (I think) you should see your asking for 100% and it will be closing it, to force the boost to drop and the fueling to go rich.

The boost fluctuation looks to coincide with timing pull (remember mine was doing the boost fluctuation thing too), but it doesn't seem to be going lean at that point (and neither did mine), but I guess the ecu could be doing other stuff in the background to try and compensate somehow (purely a guess).

Yeh the graphs are sound

So I got it completly arse backwards then lol

Whats now confusing me even more is that timing pull is minimal on the WOT run, yet on normal driving its still all over the place.

So what causes laen at high RPM I wonder.

I can't help but think back to this last year, which a fuel fixed for a few weeks, then the change of maf http://www.briskoda.net/forums/topic/239172-negative-pressure-q/page__st__30#entry2844454

Same issue ...gotta be

You have maximum air flow 166g/s@5200rpm which imho is a little low down. It should be around 5600-5800rpm. And according to this data you have roughly 207hp (crank).

This could be a problem with MAF sensor, showing less air flow than actually flows through the TIP or your fuel pump needs to be upgraded.

You have maximum air flow 166g/s@5200rpm which imho is a little low down. It should be around 5600-5800rpm. And according to this data you have roughly 207hp (crank).

This could be a problem with MAF sensor, showing less air flow than actually flows through the TIP or your fuel pump needs to be upgraded.

Thats true about the MAF, I've got old logs where it's pulling over 200. I've tried two lately, both the same, I can't see how the fuel pump being "upgraded" would make a difference as the car ran fine for 5.5 years on the standard pump.Replacing maybe be but upgrading ??

I have swapped the pump for another 1.8T one with no difference.

Thats true about the MAF, I've got old logs where it's pulling over 200. I've tried two lately, both the same, I can't see how the fuel pump being "upgraded" would make a difference as the car ran fine for 5.5 years on the standard pump.Replacing maybe be but upgrading ??

I have swapped the pump for another 1.8T one with no difference.

The fuel pumps are getting old and tired (both the age and the mileage play a part here), they do start to struggle to keep the supply constant.

The fuel pumps are getting old and tired (both the age and the mileage play a part here), they do start to struggle to keep the supply constant.

Yeah granted but do I need to upgrade ??

Whats the difference in prices between boggo and upgraded(LCR I guess) ?

Yeah granted but do I need to upgrade ??

Whats the difference in prices between boggo and upgraded(LCR I guess) ?

About £50 retail iirc

So what did you pay for your LCR one, PM if you like ??

I have paid my 250eur

My mistake, looking on eurocarparts the price difference is less than £30 after discount

So if I bite the bullet and buy a new pump, do I but 3 or 4 bar ??

Like I say it runs fine on a good 3 bar ?? well it did lol

For the sake of under £30, get the 4bar.

I'll do a little test and rewind it a year, I got a new fuel filter here, so I'll try that first.

If not new pump Monday I reckon.

Now I'm really confused

New fuel filter fitted, swapped all billys parts back over whilst I was, thats MAF, DV, N75 and FPR.

Open the throttle on the bypass today, seems to have regained it's mojo.

I'm not quite ready break out the champagne yet mind you.

Finally got to use the boost leak tester today too. How fun are they lol

After swelling the pipes hard and getting 10 psi in there, the area around the hockey puck valve was hissing but no soon as it was touched it would stop.

Then it wouldn't do it, then it would. I need a can of smoke really.

Sounds like your finally getting somewhere

It does, but I'm still sceptical, I'm gonna call in the airport later and see whats really going on !!

It does, but I'm still sceptical, I'm gonna call in the airport later and see whats really going on !!

Don't forget to get some logs whilst your there

First three gears are much better, still a little sluggish but not noticeable unless your watching the boost gauge.

Fourth and fifth,well I let the file tell the story

Boost maf O2 2003.xls

It's still leaning out above 5k, but I notice the MAF is dropping off at roughly the same point. So is it possible it's drawing unmetered air which would lean or have I got that wrong ??

So a new fuel filter perks it right up for a bit like last year .... Did somebody say fuel pump

Or both of the above lol

Or even neither of the above, I'd rather be sure before shelling out more cash.... Then again wouldn't we all lol