What do your boostmeter read when on idle?

[SSQ4]

I have just mounted the boostmeter, but i think something must be wrong!
On idle the meter reads -6!!! when i rev the engine i only see -4!! :shock:
I cant take it for a spin because my license is at the police :roll:
Anyone got an idea?

[FletchQ4]

thats fine mate , the engine creates a vacuum so until your actually under load it wont boost above 0 :wink:

[Steve Webb]

I'll second that, -0.6 when at idle is fine, if you blip the throttle a couple of times quickley you should see the gauge go up to 0.

[SSQ4]

Thanks guys! :D
I'm lokking forward to get my license back in a months time! I've only driven the Q4 a month after buying it in january :!:

SS

[q4fatboy]

Just fitted my boost meter and get -0.3 on idle but it only goes up to +0.3 no matter how hard it is driven.

Any clues as to where I should start looking ?

[AlfaJack]

Where have you connected the pipe?

[q4fatboy]

I have connected in to the pipe that runs along the back of the battery. There was an picture on the old forum. Is this correct ?

Where should I have connected it to ?

[FletchQ4]

it should connect to the small bore pipe that runs from the nipple on the dump valve to the inlet manifold, the pressure in the manifold forces air down this pipe to the dump valve keeping it closed while boost is on so when the throttle body closes the air drops letting the valve open.
hope that makes some sense.

[Steve Webb]

I was under the impression that any of the small bore hoses was ok. The easiest place to install it is to insert a T piece into one of the hoses going into the inlet manifold.

Steve

[q4fatboy]

Problem solved. The rubber connection to the dump valve was split. A new connections and boost gauge working properly.

-0.6 through to 0.7 now, is that about right ?

[Steve Webb]

-0.6 > 0.7 is the normal range for the turbo, BUT you should see upto 1.1bar when the overboost system is working correctly. The overboost only works in 3rd /4th /5th gears, and as controlled by the ECU and a small cylinder that is fixed to the slam panel to the right of the radiator (when you look at the engine from the front of the car). The cylinder has 3 small bore hoses attached to it, along with 2 electrical connections. Usually something here has come adrift making the overboost inoperational.

Steve

[q4fatboy]

OK, next job is to find the overboost. Will look next weekend when I am fitting a cone air filter.

Will update you guys on how I get on :D

[SSQ4]

I,m back... with a license to drive :D
The first two weeks of driving with boostmeter in place was dissapointing... it only reads max 0,2 !!! Then last sunday i changed sparkplugs and airfilter... after that i started to look over all the smallbore connections on the inntakemanifold, and suddenly i found the missing link, i think it is the one that controlls the boost. i changed the rubberhose and went for a drive... YES!!! what a difference at last it goes like hell when the needle goes past 3000 rpm, but still i only see 0,5 and max 0,7! Today i looked over the connections on the pierburgvalve, but cant say that i solved the problem... any tips regarding the missing overboost?

SSQ4

[Juan AR155Q4]

Have checked all hoses? Look at the big ones too (intercooler-turbo, throtle body, etc). Check also they are not broken.

If everything is OK, the turbo should be the problem :(

[SSQ4]

I have only visualy checked the hoses... I'm going to buy some siliconehoses tomorrow and change them! I don't belive the turbo is broken, the car has only covered 65000 km! and there is no smoke or noise.

SS

[155-tbo]

Check your overboost valve (Pierburg). It is maybe broken, so you don´t have any overboost. I have same problem, when I bought my car. I replaced it to manual boostcontroller and now I´m planning to replace it electronical boostcontroller.