V6 stalling/poor running

[stuvaux]

looks like the stripdown will be a job for sunday morning!  (I work nights wed-sat, so not a lot of time till then!)

as far as the hiss goes, it only seems to do that occasionally, and only when i turn the engine off
it lasts for a couple of seconds at most
there are no splits in the inlet pipes
maybe i've loosened/damaged one of the vacuum pipes while messing with the IAC valve.......

stu

[Marks DTM Calib]

If you look at the rubber piep that connects to the idle valve there shoudl be a smaller pipe which branches off and runs under the plenum......this connects to a small fuel pressure regulator on the fuel rail....is this all intact?

[stuvaux]

the small pipe that branches off does have a very small split in it, which i have put some tape over for now...
as far as i can see, it is still connected to the fuel rail

stu

[Jones]

Hi take a look at the brake vacum pump pipe mine had a hole in it. this was cause with my car idling poor  

[stuvaux]

ok thanks mate
i'll check that properly when i strip the engine on sunday....

thanks,   stu

p.s. the problem has not appeared in the last 2 days, doing only short journeys to and from work..... but i'm expecting it back anytime soon!........

[stuvaux]

i stripped the car yesterday, and cleaned all the breathers, checked vacuums etc.
all were intact and connected properly
problem is still there......
on a paperclip test, i am now getting codes 57 & 73
i did clean the iac valve again today though, and left the wiring disconnected when i tested it - so that would explain the 57 code (IAC valve - interruption)
code 73 relates to air flow sensor - low voltage
is this easy to check, or is it possible to clean it?

thanks, stu

[TheBoy]

the 73 may be genuine, or may be a false caused by air leak...

[stuvaux]

thanks for all of your help

i've now changed the air flow sensor
there was also a small split in one of the gas pipes that go into the top of the engine, into the inlets
i have also sealed this for now

at the moment the car is running fine again.....i'll just wait and see what happens!........

stu

[stuvaux]

hi guys
there is now a leak from the black breather box on top of the engine, causing a strong smell of gas

is it possible to buy the round seal that goes into the plenum
if yes, does anyone know what the part number is?

thanks,  stu

[stuvaux]

mark, do you know the part number for the rubber seal for where the breather box on top of the engine goes into the intake?
also, the seals that go into the throttle body?

i've phoned three vauxhall dealers and they don't seem to understand what i'm going on about......no surprise there then....!

thanks,   stu

[Marks DTM Calib]

As it happens....yes I do.

Breather bridge to plenum seal (1 off) 90467543 90p+VAT each, retail
Breather bridge to throttle O ring (2 off) 90500983 43p+VAT each. retail

[stuvaux]

thanks a lot mark

i have now ordered them from a dealer, i have to pick them up tomorrow

the car is now running fine on petrol, but on gas it has a bad misfire
i think this is due to the air leak from the breather box - as the gas is fed directly through the top of the inlet, so the gas is also leaking from there!

thanks again,   stu

[Marks DTM Calib]

The MAF fault code is spot on for an airleak....the engine knows its using a quantity of air but, the MAF is reporting a lower quantity (and hence a lower voltage)

[stuvaux]

i have already changed the MAF anyway now - this has definitely made it run better on petrol

once the seals are changed, it should run on gas again (much better, same power, but only 37p a litre!)
problem solved....finally!....i hope...

thanks, stu

[stuvaux]

Finally.....the car is running perfectly again!
Thanks a lot to all of you who posted your advice.....particularly Mark, who was very helpful....is there anything he doesn't know about Omegas?

Yesterday, I replaced the breather box seals
The problem on gas was actually some sealant which had set inside the pipe that feeds the gas to each port (of which there are six in total, obviously!), so the car was only running on five cylinders in effect.

Thanks again,   stu   8-)