7M - Most common area for a Vacuum leak?

[menace]

Hey Guys,

I have a idle issue with my 7M.

Yes i've cleaned and also replaced the ISCV (?) but the issue is still there.

Now i'm leaning towards a Vacuum leak.

This is because the idle drops allot when i'm stopped at the lights with my foot on the brake...

Does anyone know the most common area where it would leak (Intake Manifold)?

Thanks,
Dennis

[BeRad]

stepper motor may not be functioning... theres another thing to look at.

start with the vac hoses.

[jonra23]

With a vacuum leak generaly pick up revs.

If it is dropping revs when you put your foot on the brake there may be a vacuum leak in your brake booster, Brake boosters habve a constant vauum balance on both sides of the diaphragm and when you put your foot on the pedal it blocks vacuum off to one side and lets atmospheric pressure in.

With the engine running have a listen down around brake pedal and see if it leaking, also squeeze down the vacuum hose to brake booster with engine running and see if you get the sam rev drop.

regards
jon

[menace]

Got my vacuum checked out with a gauge. Everything seems ok. The mechanic said my poor idle could be because of my injectors.

He unplugged the fuel pressure reg and the idle went fine.

Is that how it works?

[Screamn_Sleeka]

isnt the most common vacuum leak in a 7M through the head gasket

hehehe... sorry for wasting your time

[jonra23]

Does your vacumn change with your foot on the brake as you said that seemed to change idle in your first post?

When he discoonected the vacumn line to the fuel pressure regulator did he close it off so that no air was entering plenum or leave it open?

If you rinjectors are blocked I would have thought that you would have more trouble under revs/power than at idle.

regards
jon

[hamgatan]

have you vented the factory bov to the atmosphere or have a separate bov vented to the atmosphere?

do yourself a huge favour and plumb it back!

the factory bov is a pile of shit and has been known to seep at extremely low pressure. mine was vented to the atmosphere when i got it and even though it made a terrific 'look at me im so bling bling with my wanky b.o.v' whooshing noise.. it proved quite pointless because if i dropped off the acceleration i would suddenly drop below idle revs and uh oh! quite possibly stall it.. when i found some piping and plumbed it back in it solved a good deal of the problem associated with pressure leak. i did the clean the ISCV thing too and even went thru and cleaned out the whole ISCV tubing as well.. didnt work.

if youre running the factory b.o.v... throw it and replace it with the Bosch jobbie from the Saab 900 series turbo. Its far stronger and doesnt seep like the factory one. it'll cost you about 60 for the b.o.v and maybe 10-20 bucks for adequate piping to plumb it back into the intake before the turbo. ive got a pic of this in mine if u need it.

[WA_TRD_83]

if youre running the factory b.o.v... throw it and replace it with the Bosch jobbie from the Saab 900 series turbo. Its far stronger and doesnt seep like the factory one. it'll cost you about 60 for the b.o.v and maybe 10-20 bucks for adequate piping to plumb it back into the intake before the turbo. ive got a pic of this in mine if u need it.

I'm going to request this pic anyway for my own future reference..

cheers
Damo
TRD83

[ViPeR_NiPPleX]

the rubber hose that joins to the 3000 cross pipe, take of the hose clamp and make sure there isnt a split anywhere around it. Had that problem with a mates ma71.

[Negative Boost]

if youre running the factory b.o.v... throw it and replace it with the Bosch jobbie from the Saab 900 series turbo. Its far stronger and doesnt seep like the factory one. it'll cost you about 60 for the b.o.v and maybe 10-20 bucks for adequate piping to plumb it back into the intake before the turbo. ive got a pic of this in mine if u need it.

Can i request a part number if yoiu have it?

[menace]

Sorry Guys.

I forgot to mention that it's a GE...

[ViPeR_NiPPleX]

haha, yeah thats kinda important to know

Check power steering idle up rubber hoses (assuming it has them), anything between the airflow meter and the throttle body should be checked.

[amichie]

Got my vacuum checked out with a gauge. Everything seems ok. The mechanic said my poor idle could be because of my injectors.

He unplugged the fuel pressure reg and the idle went fine.

Is that how it works?

EdIT Sorry for double post the same question will read next time EDIT

Was the hose pinched off when it was pulled off the fuel pressure reg?

If you just pull it off you will create a vacuum leak and increase the fuel pressure.

If you pinch it off and pull it off you will just up the fuel pressure.

[menace]

Hey,

He pinched off the hose that he took off the regulator.

So he increased the fuel pressure...

[hamgatan]

heres that pic fellas for whoever wanted it -



Bosch Part number i cant remember.. let me see if i can find the invoice from Saab coz thatll have it on there