Club G40 Forum

Technical => Engine and Transmission => Topic started by: matthg40 on November 19, 2011, 10:08:25 PM

Title: Very low boost
Post by: matthg40 on November 19, 2011, 10:08:25 PM
Evening guys very quick question my 40 is only putting 0.2 bar of boost out when it usually puts out atleast 1.2 uve checked for leaks and all is good but still very little boost anyone got any ideas plus the charger belt has plenty of tension aswell
Title: Re: Very low boost
Post by: cheys03 on November 19, 2011, 10:15:23 PM
Throttle-bypass butterfly (the recirc one, forget the proper name) stuck open?
Title: Re: Very low boost
Post by: matthg40 on November 19, 2011, 10:54:08 PM
Ah good thinking does needing the charger servicing make any difference
Title: Re: Very low boost
Post by: PeteG40 on November 19, 2011, 11:03:33 PM
any of the pressure lines loose (to ecu etc)

or look in intercooler gauze, if there is any metal your charger has shat itself
Title: Re: Very low boost
Post by: Robin on November 19, 2011, 11:07:58 PM
Quote from: matthg40 on November 19, 2011, 10:54:08 PM
Ah good thinking does needing the charger servicing make any difference

not 1 bar of difference.
Title: Re: Very low boost
Post by: matthg40 on November 20, 2011, 02:02:16 AM
Scratching my head abit with this one
Title: Re: Very low boost
Post by: Jezza-7 on November 20, 2011, 08:42:31 AM
have you got a mechanical boost gauge?
Title: Re: Very low boost
Post by: matthg40 on November 20, 2011, 12:34:51 PM
Yes mate
Title: Re: Very low boost
Post by: Jezza-7 on November 25, 2011, 10:23:05 AM
Check your connection on the t-piece. My rubber sleeve that goes over the nylon pipe and connects to the t-piece had perished and split open.
Title: Re: Very low boost
Post by: cheys03 on November 25, 2011, 01:51:00 PM
Quote from: Jezza-7 on November 25, 2011, 10:23:05 AM
Check your connection on the t-piece. My rubber sleeve that goes over the nylon pipe and connects to the t-piece had perished and split open.
Stack unit per chance?
Mine did exactly the same
Title: Re: Very low boost
Post by: Jezza-7 on November 25, 2011, 07:28:00 PM
Yeah it was  :D

Rang up stack and they dont sell them separately either. 2 tie wraps and some silicone did the job.
Title: Re: Very low boost
Post by: matthg40 on November 27, 2011, 12:07:40 AM
Which t piece are u talking about guys
Title: Re: Very low boost
Post by: cheys03 on November 27, 2011, 03:02:02 AM
The t-piece that some people will use to fit a boost gauge, you may or may not have one too depending on your setup
Title: Re: Very low boost
Post by: Jezza-7 on November 27, 2011, 08:14:37 PM
Usually found on the small pipe coming off the top of the fuel pressure regulator going to the main vacuum pipe coming off the throttle body.
Title: Re: Very low boost
Post by: matthg40 on November 28, 2011, 03:04:49 PM
That is all in good condition anymore ideas as I want my boost back :-(
Title: Re: Very low boost
Post by: PeteG40 on November 28, 2011, 03:18:47 PM
have you checked the gauze in the intercooler (at bottom of charger to intercooler hose)

this happened to dk, his spat an apex seal.
Title: Re: Very low boost
Post by: Jezza-7 on November 28, 2011, 06:14:03 PM
Have you checked the charger to intercooler pipe? Mine split open and created a hole about the size of a 2p coin. Had boost but very little.

Can you hear any rushing of air when your driving as if there is a leak?

Where you live?
Title: Re: Very low boost
Post by: matthg40 on November 28, 2011, 08:08:10 PM
Yes u can hear a whoosh of air when my foots down and I'm in Leicester pal
Title: Re: Very low boost
Post by: Jezza-7 on November 28, 2011, 10:08:36 PM
How far is that from derby?

It sounds to me that your butterfly valve in the outlet of the t-piece is not closing properly.

Again i had a problem with boost when it just suddenly went from 12psi to 2 psi. Now on the throttle cable, where it sits in the bracket from the inlet manifold, there is a rubber bung around it and a little clip. Is your clip there? Mine snapped off causing the cable to become loose and it wouldn't shut the valve, not even 1/4 closed.

Check that. If that fails get someone to put their foot down on the accel and check to see how it operates and closes.

Title: Re: Very low boost
Post by: matthg40 on November 28, 2011, 10:53:56 PM
I'm junction 21 of the m1 matey is that all it could be then throttle body problem
Title: Re: Very low boost
Post by: matthg40 on November 28, 2011, 10:55:06 PM
The clip is presant mate in the cable
Title: Re: Very low boost
Post by: Jezza-7 on November 29, 2011, 08:53:00 AM
Yeah check to make sure the butterfly valve is closing fully.
Title: Re: Very low boost
Post by: AlexG40 on November 29, 2011, 07:08:18 PM
If you can get it to my house this week I'll have a look for you. I'm at J23.
Title: Re: Very low boost
Post by: matthg40 on November 30, 2011, 11:30:53 AM
That would be Awsome if you could mate its doin my head right in
Title: Re: Very low boost
Post by: AlexG40 on November 30, 2011, 07:13:20 PM
I'm in most of tomorrow and Friday. Busy on Saturday. PM me dude.