TOMMY_TURBO

hi every1 im quite new to the cosworth world i use my car daily and iv now encountered a problem a few days ago car was fine then parked it up went shopping come back out car all sweet apart from boost on my t34 had dropped from 20psi to 10psi checked actuater and waste gate and found waste gate arm had cracked on the weld and was loose so pulled on it and it snaped so got it rewelded connected back up and 10psi again tried tightening actuater no change so removed forged dv and boost now hits 27psi so tryed lowering it and it stays the same and everytime i refit dv it will only boost 10psi please help as im stuck also car has dyno print outs of it being 336bhp at 27psi but on the t3 but was running fine on t34 untill this happend.

chrisa3

iTrader: (1)

Sounds like the DV is leaking boost. If it has a dyno sheet reading 27psi then its obviously been running low boost at 20psi to start with. Is the vacuum pipe still attached to the DV and check for leaks in it.

I was thining the penny washer on the wastegate might have come loose (which I have seen before, it doesnt seal properly and leaks boost down exhaust), but since its fine without the DV, it would suggest this is where the problem lies.

Ive been running mine without a DV on a T34 and its been fine.

TOMMY_TURBO

but adjusting the actuater still wont let me change the boost could the amal valve be nacked

gibbo frst

iTrader: (2)

was it welded up properly by a specialist or just the top half welded back on.. if the penny inside the housing is not making a perfect seal it will lose boost.. my old turbo looked to be sealing but i put paint on the outside of the penny and held it closed only half of the hole was closing as paint didnot touch the exhaust housing all the way round.. .

martysmartie

iTrader: (1)

What he said, re the wastegate "Penny", turn your ignition on and listed, or alternatively have an assistane do it for you. You should hear the amal valve "Click", if so it's working.

Martin

chrisa3

iTrader: (1)

Just disconnect the downpipe off the back of the turbo and check to see if the washer is sealing properly. What happens is the shaft it is mounted to slides downwards and the washer doesnt sit in the recess properly. Its easy to spot if this is the problem when you disconnect the downpipe.

You could bypass the Amal valve temporarily to test, just run the pipe from the compressor straight to the actuator. A standard actuator will olny hold around 8 psi when fitted like this and a -31 will hold around 1 bar. If the amal valve isnt operating, I would expect you would get the same results bypassing it. If the AMAL is jammed shut like my previous one, it would overboost.

You AMAL valve should click open and closed when you connect/disconnect the terminal to it. It closes when the ignition is turned, diverting boost away from the actuator, and opens when power is cut to it, allowing pressure to the actuator.

martysmartie

iTrader: (1)

Not strictly true, as the valve will only have power applied to it during the duration of the fuel pump prime, so you can be thrown down a false path by thinking it's not working when it is.

When the engine is running it obtains a live feed again, so should click, by disconnecting/connecting.

Martin

TOMMY_TURBO

im having to run without bov to get over 10psi i disconected the wires to the amal valve and it boosted around 18psi about were the forged actuater is set i belive also the amal valve still clicks but does seem like it is overboosting when connected also the boost gauge bounces like crazy over 20psi with it conected

TOMMY_TURBO

also i could adjust boost with actuater before now i cant with amal valve conected

chrisa3

iTrader: (1)

Thats what I meant, sorry. When running it should get power and close. Ecu cuts power to it and it opens when max boost pressure is reached. with the engine running, you should get a click by disconencting and reconnecting.

chrisa3

iTrader: (1)

Sure you have got the pipes connected the right way round ?? I know its an obvious one but just checking.

W - wastegate
C - Compressor
R - goes back to airbox or Vent to air.

TOMMY_TURBO

i did think that myself because i only bought it about 1month ago but they all look fine when i first bought it i could adjust the boost with actuater but now cant so thinking gota be amal valve but that dont exsplain the 10psi when bov fitted

TOMMY_TURBO

tried my dads 3door amal valve today but no change also at high revs and full boost the car missfires slightly around 5k and boost gauge bounces between 20psi and 28psi constant

Paul_RS

iTrader: (4)

Buggered actuator.

TOMMY_TURBO

is there anyway of testing the actuater its a forge-31 i believe

chrisa3

iTrader: (1)

You can try and find a pump with a gauge on it (I have used the pump off my mountain bikes suspension forks), Attach it to the actuator and see what pressure operates it. Did you check the washer on the wastegate??

TOMMY_TURBO

not yet mate but i think that is ok because it runs ok at 18psi with amal unpluged and boost gauge stops going crazy to so gota be something that runs amal surely

cossie4i+

iTrader: (15)

What part of Kent are you in ?

Steve

TOMMY_TURBO

aylesford/maidstone

cossie4i+

iTrader: (15)

Im in Herne Bay.

Are you going to the Kent RSOC meet at Brands this evening ?

Steve

TOMMY_TURBO

i didnt even know there was one have got alot to do but wouldnt mind going

TOMMY_TURBO

i think you could be right mate im checking the waste gate now and there is a lot of movement and i think its maybe catching the lip and not closing fully when actuator is fitted i believe the sleeve is shot can you buy a new sleeve

chrisa3

iTrader: (1)

my mates was doing the same thing. almost as if the shaft was sitting too low in the housing. It only takes a 1mm of so for it to not seal properly. Not sure about replacing bits. In the end he had his refurb'd at CR turbos I think.

TOMMY_TURBO

update! just replaced head gasket and put new rear housing on turbo and car still only making 10psi and cant adjust boost by actuator with dump valve disconnected it boost between 25 30psi and boost gauge bounces like crazy and car pops bangs and misfires around 5/6000 rpm

cossie891

iTrader: (1)

You need to get it to a tuner mate

chrisa3

iTrader: (1)

Just a few points to check again.

With the actuator adjusted correctly, and the amal valve removed (ie the actuator plumbed straight into the turbo housing) the car should make

8psi on a -31
14psi on a -34

These are the approx lifting pressures for these actuators without boost control (amal or beled valve). These are figures from MSDs website.

If yours is boosting to 28-30psi in this state, then you have the arm on the actuator tensioned incorrectly, the actuator itself is knackered or the wastegate is sticking. It only needs to be 1/2 of hole too short, and then attached to wastegate arm. This will give you around the above boost levels.

Once your happy this is correct. You need to attach the amal valve. Even with the amal fitted it cant make less boost than the above unless theres a leak between turbo an inlet, or the wastegate is leaking boost (but this would have been apparent in the above situation also).

If its making too much boost with the amal valve fitted or the same as without it fitted, then the valves either faulty or its plumbed in wrong.

If your still not sure, id get it off to a tuner as suggested, to get it checked before you melt something.

TOMMY_TURBO

it boost the same with amal valve disconnected and with a different amal valve

martysmartie

iTrader: (1)

So it sounds like your D/V maybe the problem? What you are most likely experiencing re the misfires etc is OVERBOOST protection, in other words to much boost!

Martin

TOMMY_TURBO

only runs 10psi with dv fitted and is sweet as a nut its when you remove dv it over boost and misfires its just boost wont adjust with or without dv

martysmartie

iTrader: (1)

Yes so clearly as I say the D/V is the problem, so without this you have boost, albeit a tad to much by the sounds of what you describe.

Sounds like the actuator is adjusted incorrectly as said.

Martin

TOMMY_TURBO

no matter what you do with actuator it will not adjust boost with or with out dv it used to before this problem started also tried 3 dv and all do the same so deffo not dv could it be map sensor or amal wiring?

chrisa3

iTrader: (1)

Firstly, you say it Runs 10psi with DV fitted but 27psi without. Id say the DV is knackered, spring or vaccum not sealing under boost.

Second of all, You mention it ran a t3 on dyno sheet but now has t34.
Id say the misfire is unrelated to the DV and could be down to the chip not being setup for the T34??. Ecu is detecting overboost and cutting the amal valve in hence the misfire etc. Sounds plausable. If this is the case, you have two different issues, the latter could cause serious engine damage.

Personally, if you not 100% sure of the current map setup etc, id pay the money and have a new chip done for the current setup by someone like MSD.

TOMMY_TURBO

it did run fine before tho with t34 also without dv fitted boost gauge goes mad bounces all over the place between 20 and 30psi

TOMMY_TURBO

and i used to be able to adjust boost with actuator and now i doesn't do anythink when adjusted

chrisa3

iTrader: (1)

what are you doing with the vaccum hose when you disconnect the DV?? Is it a vent to air or recirculating type??

martysmartie

iTrader: (1)

The actuator is what controls the boost, it's a purely a physics affair, pressure overcomes the strength of the actuator will actuate the wastegate (open it) hence the name.

You could have the vaccum hoses connected incorrectly though, or one has a leak, also as said you will need a remap if you haven't done so for the new turbo!

Martin

TOMMY_TURBO

i dont know if its been remapped for new turbo coz i bought it with the t34 and it did run spot on also its a ahmed bajoo chip in ecu the rolling roads for when t3 was fitted was 4 years ago

TOMMY_TURBO

also iv been blocking vaccum hose with a screw when dv is removed

chrisa3

iTrader: (1)

If when removing the DV your plugging the vacuum hose at the DV end (ie your using the same section of hose) and it then starts gaining boost, then it cant be a leak in the pipe and has to be related to the DV. Without the DV connected, it would appear that the leak has gone, and now you are getting overboost, causing the ecu to cut power to the Amal valve, which will drop the boost (sends pressure to wastegate) which could be why the boost is dropping and rising (amal valve opening and closing).

As said by Martin, both the actuator/wastegate and DV are simple devices that just open when overcome by a set level of boost.

Without knowing the ins and outs of the map setup, your playing with fire just adjusting actuators etc. First thing I did when I bought mine was to get a new chip. £100 for a basic one from MSD, but at least i know it setup for the correct injectors, map sensor, actuator set for peak boost etc.

Thats the trouble when buying cossies. People remove parts, swap parts before they sell the car. And without knowing 100%, its just too risky IMO.

Take it to a tuner bud, and get it all setup properly, then you know your starting from a blank canvas

col93saphcos

iTrader: (2)

amal valve been jetted to suit?

colin