issues today

[flashyg]

not fully out yet , will fully report when I get back together , Thanks to all involved Mrc included. G.
Spark plugs are good and tight for sure. No problem there nothing at all , Moving along quickly. I will report asap. Thanks.

[CliveH]

Glad to hear it Gordon

[flashyg]

Am considering the 255L/H Walbro Fuel Pump, for my Audi A4 B5 RS4 Avant. Car runs a mew 4 bar fuel Pressure reg (Stock) 450 bhp at the moment but retarding up the rev range. Thinking this may well be a fuel pressure issue.
Checked so much else and now thinking, Could it be the fuel pump?

* Denotes retarding.

Time RPM MAF Throttle% %BTDCTiming
158.7 3920 113.36 40.8 30
159 4040 161.86 100 24.8
159.31 4160 243.36 100 16.5
159.61 4400 264.89 100 14.3
159.93 4600 283.11 100 13.5 *
160.26 4840 294.58 100 15
160.6 5040 300.5 100 15
160.94 5280 296.11 100 10.5 *
161.28 5440 298.75 100 15
161.64 5720 318.53 100 12.8 *
162 5920 325.83 100 15
162.37 6080 334.78 100 13.5 *
162.74 6320 335.25 100 15.8
163.12 6520 342.67 100 18.8
163.5 6720 350.75 100 19.5
163.88 6880 356.92 100 18.8 *
164.25 7120 358.97 100 18.8 *

Could any one who has replaced there fuel pump for the 255 Walbro let me know if it is fine to run on the stock 4 bar pressure regulator?

Also there appear to be many versions of this 255L/H pump which is the correct version for the B5 S4/RS4?

Where is the best place to buy?

Thanks G.

[dummi]

what did they find out about the car at MRC?

walbro i thought was just a universal fuel pump try ebay £85

[flashyg]

Broken non return valve from n80 to inlet manifold causing an intermittent internal boost leak. This was quite difficult to find as you needed the valve to stick to catch it.
New lower reading maf ( got it 1 month ago). Changed for good one.
Rattley Air box, rubber grommet installed (1bhp gain) and its right now.
And of course plugs were not tight so re-tightened. My fault.
Swapped out injectors, fixed a perished vac hose to the unit which controls the induction flap.
So no massive issues but great to get fixed. Doug at mrc was exemplary.

Still getting <beep> so logging today to try and get better idea of cause.
Will report back just in limbo at the moment.

Thanks dummi for your interest and the diagram has been a great help to me, also dazzer I am very grateful for your help and that of Ben at sportstech, David T, Nige , Clive H, KayGee (still on the job) Tartan Rob, Mihnea , Philip Walker (ya i know, helped me) Mrc, Grizz (who always tells me what I want to hear, well done) Giles, My wife and anyone whose ear I bent... My manger of course, And any one else Ive forgotten to mention or knows me, Rs246.

I am one cry baby aren't I

Thanks again G

Will report back.

[CliveH]

Nice one Gordon Glad to hear it! So many "little" things...

[CliveH]

KayGee (still on the job)

You must have some stamina Kevin...!

[flashyg]

It is decidedly so.

[flashyg]

pump replaced and still in the woods!!

[flashyg]

still no explanation for retarding and car is running .7- .85 volts on lambdas under load meaning seriously lean. Please can I have some further help regarding this it is very difficult to comprehend the cause.

I have run the car on 98-99-102 all the time retarding and running these volts.

Mihnea I need some help, Please. This has gone beyond my abilities.
I am now bricking myself as I have a mint beautiful car that is going to destroy its self and so far changed maf , dvs, injectors, lambdas, boost valves, fuel pressure reg, n75, map sensor, 249, hoses, fuel pump, plugs, no boost leaks. All knock sensors working and lambdas following each other correctly.

When I open the fuel tank there is a small vacuum but if I blow / suck on the cap this valve works.
Is it normal to need a small vacuum to open the filler cap valve.

Help needed.

[smurfbus]

just a list

fpr vacuumhose (lower fuel pressure if leaking) , fuel filter and possibly kinked fuel lines. the log did not nesessary look slow in my book but I take your word that it slower now. the timing was also between 10 and 20 so pretty good IMO depending on boost. Maybe you saw better before.

If its running lean now, it not a boost leak. Those narrowbands dont tell much so a WB would tell if its really running lean. 0.85V could be anything from 12 to 13 which is fine if boost is low.

[flashyg]

will reveal asap,

"fpr vacuumhose (lower fuel pressure if leaking)" sorry could you explain this, Thanks G.

Are peak egt 980-1000 a major concern, just for split second on hard boost?


(most importantly thanks all who are helping.)
G

[smurfbus]

if the fpr vacuum hose leaks the fpr cant get the 4bar +manifold like the ecu thinks. thats how I would think it goes but I'm not professional by any means.

EGTs that high will trigger safety maps like overly rich or lower boost until temps get back to norm.

Just did couple of fats pulls with my new K04 +#60 MRC basic code and while low boost 1.3bar had no timing correction the timing was from 10 to 21 and with sustained 1.5bar it was from 9 to 17 and highest correction 7 cyl2. havent looked at the AFs yet but I dont think I can dial it much faster on 98oct. FATS was 2.9sec rs4 trans.

EDIT: just saw the AF curves and its nowhere near where Mihnea wants them. That will effect timing and correction some but I dont know how much. It was too rich at 11 with 1.3bar and 10.5 to 11.5 with 1.5bar.

If you are lean it will also lower timing. Hows your fats now and before?

[flashyg]

3.5 hence issues G.

2.9 holey cow. But then I run 1.2 constant with short peak request 1.45 (mtm) at peak some cfs 4.5-5 max for f=tiny period hence backward step. Thinking small boost leak from non return valve , this protects the spider from positive charge thus boosting the crankcase and rocker covers.

Theory on this, all self created mind you ,is boost escapes and learned values compensate buy trimming, later on in the cycle the crankcase and rocker covers become filled with boost so the leak momentarily stops and slight lean condition occurs hence cfs and egts.

What a lovely story. Will be able to dismiss later as a load of boll$cks, but please before I check my car tomorrow lets debate as to whether this may be the cause. G

Good thinking on the Fpr definitely the case if issues on the line or the manifold its self.

You've got to be well switched on for these buggers don't ya. Love Hate!

[Paulm]

If you are lean it will also lower timing.

Leaning out the mixture increases timing as a leaner mixture burns quicker