RS2 Boost Problems

[montyrs2]

Hi all. I have just joined here and have a 1995 Import RS2 in Blue.

To cut a long story short the car starts and runs very well, but at approx 4300rpm it dumps all the boost and runs flat as a pancake from then on.

I have replaced the ECU as this was faulty, I have also replaced the Inlet Air temp, Barometric Pressure Sensor,Coolant sensor and Boost valve. The first three came up as faults on the old ECU, the boost valve was a speculative change.

Now however I simply do not have the money left to continue guessing. Has anyone had a similar problem of know of any possible fixes or things to try? I am in the process of getting a boost gauge so I can see exactly what the boost is doing but to me it feels like it goes altogether.

All help much appreciated.

Monty

[newsh]

First thing to do is pressure test the inlet tract, it could just be a boost leak, quite a few on here have a test kit to borrow, where are you located?

[alg]

WGFV comes to mind

[andyg plym]

knock sensors?
although 4300rpm seems quite high for these to be broken. 3500 maybe

[ericd]

Hi all. I have just joined here and have a 1995 Import RS2 in Blue.

To cut a long story short the car starts and runs very well, but at approx 4300rpm it dumps all the boost and runs flat as a pancake from then on.

I have replaced the ECU as this was faulty, I have also replaced the Inlet Air temp, Barometric Pressure Sensor,Coolant sensor and Boost valve. The first three came up as faults on the old ECU, the boost valve was a speculative change.

Now however I simply do not have the money left to continue guessing. Has anyone had a similar problem of know of any possible fixes or things to try? I am in the process of getting a boost gauge so I can see exactly what the boost is doing but to me it feels like it goes altogether.

All help much appreciated.

Monty

I don't really understand your fault finding process, if the ecu was faulty and indicted 3 items, what made you think the ecu was faulty and the errors valid and not related to previous problems ? , also was the car "chipped", where did you get the replacement ecu from ?, what are the current codes on this ecu if any ?.

if you can't get a pressure/leak test done , check all hoses/clamps, maf and its condition and connector, delete all error codes from ecu , take it for a run, report any errors you now have

HTH

[Tomquattro]

Coil packs?????

[andyg plym]

Coil packs?????

from recent experience coilpacks normally cause a mega-misfire. had the same problems,but its easy to notice when they are fooked.

[montyrs2]

I found the faults original faults with the car using a Vag fault code reader. Replaced what it said was faulty and then checked everything I knew how befor taking it to Dialynx to get them to have a look at it. They checked it over, inlet leaks etc and found the fault with ecu. At the time it wouldn;t cold start very well etc as well.

I then bought a brand new Audi ECU as previous ECU and car was standard. the only fault code it reads now is a low idle, which I hope to adjust tomorrow. it currently idles just under 800 - 700 ish.

When the boost goes it keeps going to the red line but you can feel the boost go at approx 4300 and then it is def not as urgent as it should be, i.e my mate pulled away from me in his girlfriends MX5!

After getting the new ECU etc not a shy bill, I can't afford to go throwing stuff on it without some reason etc.

I'm in Oxford so plenty close to MRC and Dialynx etc but just currently don't have the money to give them a blank cheque!

[montyrs2]

PS engine accelerates quite smoothly I really don;t think there is a misfire, i've never owned a 5 cylinder before but have had misfires on 4 pots and this is nothing like a misfire on those.

Also if I disconnect the pipe from the boost valve to the wastegate it goes very well indeed. I've only done this for 100 yrds as know it will lead very quickly to a full engine rebuilt. Hence turbo etc working well.

[andyg plym]

mate id defo just do a boost leak test,now maybe the wastegate diaphragm,£38 from www.vagparts.co.uk
could be a leak on the intercooler pipe-to-crossmember. do a search for the mark-h mod,cheap as chips too.
My advice after having 3 s2's now is to get it tested for leaks

[A80Avant]

if it doesnt pull as good as it should,maybe you should also concider the MAF.Lots of different problems can be caused by a faulty MAF and it can be it.Before buying one,you could also try to find someone to lend you one and see the difference.
By the way,i know it is too late,but it was a wrong move to replace the ECU with a new part,when even Tots from switzerland can provide it with 600-700euros and all his stuff work just fine.

[ericd]

I found the faults original faults with the car using a Vag fault code reader. Replaced what it said was faulty and then checked everything I knew how befor taking it to Dialynx to get them to have a look at it. They checked it over, inlet leaks etc and found the fault with ecu. At the time it wouldn;t cold start very well etc as well.

I then bought a brand new Audi ECU as previous ECU and car was standard. the only fault code it reads now is a low idle, which I hope to adjust tomorrow. it currently idles just under 800 - 700 ish.

When the boost goes it keeps going to the red line but you can feel the boost go at approx 4300 and then it is def not as urgent as it should be, i.e my mate pulled away from me in his girlfriends MX5!

After getting the new ECU etc not a shy bill, I can't afford to go throwing stuff on it without some reason etc.

I'm in Oxford so plenty close to MRC and Dialynx etc but just currently don't have the money to give them a blank cheque!

run the ouput tests under vag-com,to check isv and wgfv, you should be able to hear them both click on activation under these test

[alg]

I am sticking with WGFV at fault or responding to another fault leading to mechanical boost only. Mine did this with a a broken wire to the WGFV that we eventually found at MRC. But if you have full vagcom follow Eric's advice above

[montyrs2]

I don't want to sound stupid but what do you mean buy WGFV? I've never heard this term before.

I searched as best as I could for a replacement ECU, but to be fair at least buy buying a new one I know that there is no fault with it!

f the wastegate diaphram was gone then would it boost fully with the boost valve to wastegate pipe disconnected? Which it does. Does anyone have the kit to test for leaks etc in the Oxford area, can be a big area, or some spare sensors MAF etc. Then if possible spend an afternoon swapping bits to find a possible fault?

[A80Avant]

WGFV is the wastegate frequency valve located at the hose that connects the maf with the compressor side of the turbo,near the diverter valve.
could be the same as the valve you mention as :boost valve.If you are meaning the diverter valve,then the WGFV is the one with 3 small plastic exits,one for the wastegate,one for the turbo compressor and one for the hose of the MAF