It doesn't want to boost
Turbo Mini Forums

I've started my car now, but when idling, the boost gauge drops to -9psi. I seem to recall that it should be 0 on tickover.

What have I done incorrectly? Is it possible to have a leak somewhere in the air lines that causes the pressure to drop so much?

The gauge is mounted on the line going from the inlet to the dump valve.

boost gauge needs to be mounted between the buterfly and the head in the manifold usaly were the servo mounting is (thats were ive got mine)

but -9( well mine reads -15) is the right reading when ticking over and cruising but will only show 0 or boost when you put your foot on the peddal further eg flat out and then she will come on boost, just worry when you put your foot down and get no boost.

hope this helps and good luck just hope you dont get to many gremlins unlike me put you will no doubt get a few but thats all part and parcle of it all.

always looking for them bigger bunches of bannanas

After taking her (him) for another spin, it's clear that it does boost. But, the boost gauge will not exeed 0psi even if it comes on boost. I can tell it's boosting as the fuel gauge rises as the boost gauge should do.

Have I got to a small diameter boost gauge hose? I've used a Minispares oil pressure gauge hose/tube

Edited by Vegard on 26th Jul, 2005.

Diameter of a hose should not affect the pressure transmitted along it to that degree. Hose bore will affect FLOW down it, but static pressure (as transmitted to a boost gauge) will not be GREATLY affected.
I'd guess that you need to plumb the take off in somewhere else........

Have you plumbed it in after the one-way valve?

ive got exactly the same prob on mine? ive also tried plumbing the boost gauge into the line from the plenum chamber to the regulator to see if it will at least show + boost figures and still nowt. reads below 0 on tickover and about .2bar on full boost in 4th, and thats at about 8 or 9psi i think. a slight amount more and the overboost valve opens which is 10psi standard isnt it?
steve.

doh! why did i start messing with it!

have you got enough preload on the actuator as ths can cause probs as well as the waist gate not being shut properly.

but could be just a plumbing prob on gauge. my fitting screws straight into the top were the one way valve use to fit on the inlet manifold and reads ok give that a try.

always looking for them bigger bunches of bannanas

You should run a seperate line for both the DV and the boost guage.

The Guage should indeed read a negative pressure (or vacuum) at idle, which should drop to 0 as you floor it and then as the turbo spins up, come up the scale :)

Ideally you want the boost guage after the throttle butterfly (I run mine off the dissy take off). The reason being its good to see the boost going into the inlet manifold ie what the engine consums, rather than the boost in the plenum.

Alex

AlexF

Well, as it is now, the gauge is definately connected to the inlet. The pipe going from thne inlet, into a T-piece which leads to dump valve and gauge. The thing is that on my last gauge it didn't show as much negative boost, and it was connected the same way.

One way valve?? WTF??

One way valve... to the servo or the emissions junk (think that red can thing Metro's had!).

If your DV is leaking (very possible at idle or on boost if its flocked), you could well be loosing all the signal to the boost guage.

Alex

AlexF

Indeed I can. How do I tell if hte DV is leaking? I've cot a valve that was included on the Cossie Intercooler. Could I plump that one on and see if there's a difference?

take the DV off... its a crap noise anyway!

Alex

AlexF

just block the dv off after the t piece using a g clamp or something simalar and try it if there is still no joy the clamp of the pipe to the actuator and give that a go but be carefull as you will get plenty of boost but at least this will see if the acuator is working properly or is set to light which can cause the waist gate to flutter and you loose boost, buy the way is doesnt need to move much for it to do this believe me.

but the gauge should read ok the way youhave plumbed it in, sounds like a different root to the problem.

always looking for them bigger bunches of bannanas

maybe gauge is faultty, have you tested this on foot pump maybe?

Team Racing

Thanks for the tips.
Gauge is a brand spanking new Ractech one, so I take it that it is working.

assumption is the mother of all fuck ups!

assume nothing!


alex

AlexF

Jim's racetech gauge was doing strange things at Avon...

yea, mine is now fauty after around 12 hours of use

Team Racing

Hm.. I'll try to bolt on the old one and block the dump valve.
I really would remove it as you say as I hate the Woos (geddit?) sound.

chatter!

It rocks!

alex

AlexF

yeh, chatter may rock, but its kinda a exppensive noise!!! lol!! at least the chav sneezing is free!

And on the 7th day........... God created turbochargers!

Care to explain nutter?

Alex

AlexF

cant say i understand it completley.... but a quick search turns up this....

http://turbominis.co.uk/forums/index.php?p=vt&tid=1919

explaining that its actually the turbo stalling, which i was under the impression was very bad, and leads to a much reduced turbo life.

could very well be talking complete bollocks tho. i often get the wrong end of the stick!!!

Pete

Ps, alex, you might recognise the person who made the comments on that other thread!! lol!!

And on the 7th day........... God created turbochargers!

use a adjustable dv so it doesnt dump much air so you get less lag but a bit of gary boy wooosh.
lol

always looking for them bigger bunches of bannanas

I've now driven the car for the first time.. Once the turbo spools up, it stalls, and then completely dies.
Fuel pressure is 3,7 psi on idle, and increases when on boost. Fuck the boost gauge, it's faulty.

Could it be that the new Sierra Intercooler is so much more efficient than the ERST2 one that it now runs lean??

What other things should I check? It feels as it gets no fuel.