bleed valve to blame??
Turbo Mini Forums

heres the problem im having and its got me stumped...with the bleed valve wound completely shut (lowest setting) the car pulls cleanly and reaches about 2psi at 4500revs, i having been revving it more than this just while im gettign it set up... then when i wind the bleed valve up it doesnt even reach 0 on the boost gauge and strutters above 3k revs.
just cant understand why with the bleedvalve wound in it would make more boost than with it wound up ?
is the bleed valve kanckered do you think? so is just bleeding all the boost off once its wound up and only hold boost with it closed

open to suggestions
thanks

Ben

Edited by Bman on 18th Mar, 2010.

ben,is the valve in the line to the fuel pressure reg or the float bowl ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

im not sure if ive misunderstood the question, but ive got the bleed valve fitted in the line from the actuator to the turbo

Does the valve need to be a certain way round?

yeh thats what i was thinking but it seems to act the same way both ways round

The fact that it only makes 2psi at 4500rpm would lead me to suggest you have someone competent look at it, as clearly there are problems.

Where is your gauge taken from ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

hmmm , that sounds ok . if the pipe is only on the turbo and the actuator ,then it wont reduce fuel pressure if you bleed off some pressure .sometimes people put the bleed into the fpr line ,and as you bleed off boost the pressure goes down ,wilst the boost pressure is going up.

sounds a bit to me as if your fuel pressure isnt going up with boost ,so you get over 2 psi and it dies ?

Edited by robert on 18th Mar, 2010.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

well the turbo seems to spool up nicley..the car doesnt smoke or anyother way point to any big problems. literally only when i i adjust the bleed valve up it starts to mess with everything... would the actuator arm play any part in it ? as it could be that when the turbo went for a rebuild they may have adjusted the length of it??

the boost gauge runs off the top of the inlet manifold, which is where it was mounted from recently and worked accuratley previosuly.
aologies if im asking any stupid question, my turbo mini knowledge is getting a steap learning curve

sorry rob only just saw your reply.

yeh literally when the cars at its lowest boost setting it pulls clean and well, i dont rev it too high but it feels nice and positve..then when turning up boost it starts to jault and stutter as the revs pickup over 3.5k....the strange thing is that the boost gauge doesnt even reach 2psi with the bleed valve turned up, but turned down it does ..because i also thought it could have been a lack of fuel due to more boost but its essentially boosting less.

Edited by Bman on 18th Mar, 2010.

no ben, ask away , its the only way to learn , id think the rod should be ok , its just preloaded half a hole normally .hey , you couldnt be sucking the inlet pipe flat on the turbo coiuld you ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

thats a possiblity actually, because it does feel more like its getting too much fuel / not enough air and maybe as the boost is trying to increase its flattening the inlet.. my biggest problem is the sheer lack of access ive got to the pipe..i only managed to get it on when ihad the turbo and manifold half out.

do you think its worth me trying to get a jublie clip round it to rule out the possiblity its kinking on he bend

I would start by taking the bleed valve off and checking that the actuator pre-load is right. Possibly increasing it a bit.

Once you have say 5psi boost, fit the bleed valve and try to get some more.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

yeh i think ill give that a try..how do you adjust/increase the preload ??
its probably been asked alot , so i can search for some previous threads if its more than a a couple seconds for you to explain

Just screw the end of the rod in towards the actuator by a few threads. You will need to remove the little C clip and pull the rod of the lever first.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

thanks boys ill give both these ideas a try.. i had to disconnect the actuator rod previously so theres a damn good chance i twisted it out alittle refitting it...ill give you update how i get on :)

i can pop over and have a look the weekend if you want, i will have a look for my fuel pressure gauge as well

Ben.

When you have the C clip off and disconnected the actuator arm from the wastegate lever, pull the hose off the actuator and put a foot pump on it.

Gently depress the footpump and see if the rod is extending out of the actuator body.

That way, you can tell a) if you have full extension of the rod and b) if you look at the gauge on the footpump you can get a reasonable ideal of when it starts to operate.

Following on from what Robert said about fuel pressure, the other thing I'd recommend is fitting a Tee piece from the fuel pipe that runs between the FPR and carb. If you run a hose from the Tee, to outside the bonnet, connect a pressure gauge to it and cable tie it to one of the wipers, and assuming you have set your FPR to 3-4 psi at idle, when you come on and off boost, you should be able to look at the gauge whilst driving the car and see fuel pressure rising 3-4 psi always ahead of boost. If you are getting 2 psi boost, you should see 5-7 psi fuel pressure and so on..... Avonbar sell these gauges for about 15 quid.

This will allow you to confirm the FPR is at least working as it should as you come on boost but it does not necessarily tell you that this fuel pressure is getting through to the jet.

It's also worth you reading up on TurboDave's 'Tee Piece Trick'. Whether you will need to undertake the tee piece trick is debatable but the thread will give you a clear idea of how boost and fuel interact within the float bowl area of the carb and how important it is that the plenum to float drilling is clear.

It does rather sound like either the engine is being starved of air or fuel. Also worth checking the carb hoses are not split or perished, particularly the part throttle lean off pipe.

In terms of ignition, have you checked the timing at idle with the vacuum pipe disconnected ? Worth doing with a strobe and making sure the figure is not miles out.

Give me a shout if you get stuck, I can always pop over. You have my e-mail address.

Good luck.

Richard.

Edited by turbominivanman on 19th Mar, 2010.

Minivanless, but reluctantly happy living with the decision. There'll be another one day.
http://www.youtube.com/profile?user=minimadmotorman#p/u

if you dont think the bleed valve is working correctly take it of and reconnect the vacume pipe as it should be and see what happens then.

thamks alot for all the advice, i really apreciate any help i get... im going to spend a few hours on it tomorrow to see if i can figure out whats going on.

thanks for all the info richard i may well drop you a call tomorrow, and will keep your number to keep you updated on the RR day .... wolfie , as your probably closer to my than rich is ? id definatly be up for you heading over to give the mini the once over and see what you think. ill drop you a pm with my mobile number etc.
thanks all for the input soo far, hopefully be running at full steam ASAP

Do you have a wideband fitted? if not this may be a good time, especially if the problem turns out to be fuel starvation.
Have you blanked the plenum valve?

im definatley looking into adding some addtional gauges etc and an AFR gauge is high on my list ..the plenum valve had been plugged temporarliy at the minute and its a good enough job to stop any big boost leaks etc but itll be coming off tomorrow anyway to get a decent blanking plate over it...im just on my way out now to take the bleedvalve off and adjusting the actuator rod ..then will take it from there... my list of new things to buy is growing by the day :)

update so far

too the carb off today, checked no holes were blocked and the right gasket was o nthere etc, made sure it had the right oil in it (had hardly any whoops) sorted out the plenum valve to get that blocked off properly...friday checked the actuator arm and that was all correctly adjusted so put the bleed valve back on

so fars it running much better, obviosuly due to me getting things sealed up better and the oil in the pot etc.. just a test to do o nthe actuator using a foot pump as rich suggested, as im getting a gut feeling its not working as it should. and to bodge o my fuel pressure gauge to see if the fuel pressure is rising propelry which if its not will have ot be the fuel pump as the fuel pressure reg is brand new.
on the plus side although i havent got it sorted yet i got a few other jobs sorted whiel the carb was of ..so silver lining and all that

huuuge thanks to rich so far whos been giving me some great advice over the phone all weekend

No probs Ben, any time.

Just hope you can pin it down before the RR day on 10th April then you can really wind it up.

If you need a spare pump to run some tests, you can borrow one I have. I also have a good spare standard actuator (starts opening 2 psi - fully extended at 7 psi) but I'd be interested in seeing if yours is working correctly with th efoot pump test and that your FPR is rising ahead of boost.

Richard.

Edited by turbominivanman on 22nd Mar, 2010.

Minivanless, but reluctantly happy living with the decision. There'll be another one day.
http://www.youtube.com/profile?user=minimadmotorman#p/u

thansk rich... ill def be doing the actuator and fuel pressure test in the next day or so..just trying to sort an oil leak quickly first, just waiting for my dad to make me the new gearbox breather pipe at work, as the one on there at the minute is leaking really badly.
ive noticed tho that my fuel pump is ALOT louder than it used to be, i could only hear it opperating if i got right up close to it before but now ican hear it buzzing away from inside the car (my cars stiipped out but even still)
so i think ither way its on its way out.

so ill take you up on the offer to borrow your fuel pump if the fuel pressure test shows somethigns not quite right