HELP.....dieing on boost
Turbo Mini Forums

another problem! the car keeps losing all power when it should be coming on boost. any idea's?

Edited by Nick on 24th Apr, 2004.

Wrong plumbed in carb or regulator?

Carb balance pipe (runs from front to side of carb might have a split / crack in it. I suggest replacing it anyway just to be sure.
It could also be the 'anti-run on valve (if fitted) is faulty, or that the pipe going from the side of the carb to the valve is split...
If none of those, check the pipe from plenum to regulator.
If ok, you need to do some pressure testing.
Get a Gunsons lo-gauge and tee-piece it into the fuel supply to the carb. The pressure should rise as you approach the boost transition, then increase proportionally thereafter. If the fuel rises with boost and doesn't drop when the 'missing' starts, then there isn't a problem with the regulator or pump.
Next thing to try is connecting it to the pipe that the 'anti-run on valve is/was fitted to. Again, the pressure should rise before you start boosting. If it doesn't, there is a problem with the gasket between the plenum & carb, or the internal porting on the carb. you can put a tee-piece into the pipe from the plenum to regulator and connect it straight up to the pipe where you were just measuring from for a quick fix however!

Hope that lot helps!



with boost. If it doesn't,

also what air intake ducting do you use? as this can close up cutting power!
and check that your fuel filter in the tank isn't blocked!

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

here's how the carb/regulator is connected. as far as i know this is right?

i'm hoping its the carb balance pipe thats causing the problem as the pipe out of the carb had sheared when i bought it, i thought i'd bodged well enough but i just checked it and the pipe fell out in my hand.

the anti run on valve is working fine, as is the reg afaik i took it apart earlier and the diaphragm is fine no splits etc.

pretty sure the plenum/carb gasket is fine as i fitted a new one the other day when i put my "bling bling" plenum on. the gasket doesn't obstruct any of the holes in the plenum anyway.

oh well, i'll give that pipe a try tomorrow and hope that it works.

cheers for all the advice dude! :)

i'm not running any air ducting at the moment as i haven't got it ready for the road yet, still trying to figure out how to get the pipe down there waht with the actuator and bottom hose in the way :)

put a clamp on the anti-run on pipe to be sure...

nope, still no boost. looks like im gonna have to take it all off and run it N/A for the riv run

Correct gasket between plenum and carb?? the extra hole so the fuel bowl in carb is at boost pressure??..maybe or has someone covered that one??
actuater connected to waste gate properly?

Try the 'tee piece trick before taking it all off....

t piece trick? whats that then?

yeah the 'ol tee piece trick?..what F'kin trick?..i am lost..giz a clue TD..

Edited by turbodave16v on 26th Apr, 2004.

I.e. boost the anti run on pipe as dave suggests. I tried it with mine but it didnt work, its to bypass the internal passages of the carb.

It is a case of going one by one through the checks, it can be too much. Its much quicker to go through these checks and fix than convert to NA. Plus the power wont be too great on NA with a turbo build.

right, i'll give that a try now then. i tried everything else, missed that one out, d'oh.
the only other bits i haven't been able to check are the pressures as i dont have a guage yet.

just to be sure, my anti run on valve is t pieced into the servo piping, this is the right place to have it isn't it? as its where it was as standard.

Edited by Nick on 26th Apr, 2004.

still no luck with the t piece trick. gonna take off the plenum again and double check the gasket, if thats fine then i'll have to raise some cash to go find a presure guage.

No, not into the servo piping...
The pipe that runs from the plenum to the top of the regulator.

http://www.buy-secure.co.uk/gunsons_test_tune.htm
LO-Gauge available here... Also try Halfords or local motor factors.

If you are going to Newquay, i could have a look if you want - I can bring my lo-gauge and other test equipment. If i find the problem, you can buy me alcohol in a quantity of your choice, depending how gratefull you are...

thats where my anti run on vlave was though, so i t pieced it into the pipe from the plenum to the carb.

where should it be on the turbo? in your earlier post it said its connected to the carb. of the three connections on the left of the carb as you look at it ive got the bottom left as fuel in which must be right as it runs, the top one as the balance pipe. but i have no idea what the bottom right is for, i thought it was for the breathers to go into but now i'm guessing this is where the anti run on valve goes?

sorry for all the questions dude. if you come find me at the riv run i'll glady supply you with beers :)

check out the carb connections post in "how to" it shows all the connections to make sure you got it right, pictures are worth 1000 words

If you have the pipe at the same height, but around 1" forward of the 'fuel in' pipe open to atmosphere, it WILL die on any kind of boost

Edited by turbodave16v on 26th Apr, 2004.

Just realised - you're using the 'metro / mini 1275' anti-run on valve... This is not suitable for a turbo application.
The 'turbo' valve has a 1/4" hose and is connected to a tiny solenoid valve going into this pipe 1" forward of the fuel in. It closes when 12v is applied to it, or, you can replicatre this with a shouldered bolt or piece of round steel wedged into the pipe...

You also need to get a 'one way valve' in the pipe between your inlet and servo. These are found on many, many cars - not just turbo ones (almost every ford since 1980 for example). Just make sure you plumb it in the right way - ie so the connection at the inlet can suck, but not blow!

If you don't fit this, you'll do strange things to your brake servo, maybe even damage it...

woohoo. dave you are a lifesaver! i got BOOST! used the t piece trick properly this time and it works.

definately worthy of a few pints at the riv run dude! :) :) :)

a few pints will kill dave!!!

Team Racing

boost is the baby!

can i borrow some?

see you dudes at Newquay!!