Omega Owners Forum
Chat Area => General Car Chat => Topic started by: Webby the Bear on 17 January 2013, 13:24:57
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I looked for vacuum leaks with carb cleaner and to be honest (due to space being tight in the engine bay) I'm not totally satisfied that I did it properly.
Plus there was the worry of it catching fire due to the carb cleaner being flammable.
So I searched a bit and found this....
http://www.youtube.com/watch?v=zMok2y05jNE
What do you think? Anyone tried this?
I'm going to give it a go this weekend.
:y
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I use my ear but dont even start looking unless I have carreid out a vac gauge test to see if there is the need to do the investigation in the first place.
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That's interesting... never heard of that test.
You reckon this will work for the DIYer? Seems to on the vid :y
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If its a small leak probably no, I have never had much success with the carb cleaner one either.
The issue is that when the engine is running there is a lot of 'windage' from the rotating parts such as alternator, aircon, belts etc.
Given the vac leaks are often tiny they dont show up unless its a big one (which you could spot using your hearing)
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What about this http://www.ebay.co.uk/itm/DJ-DISCO-PARTY-MIST-SMOKE-EFFECT-SPRAY-CAN-NON-TOXIC-/190778999033?pt=UK_CE_DJ_equip_SmokeMachines_atmospherics_ET&hash=item2c6b5080f9 for the hard of hearing like me ;D
I am quite lucky in having access to 3 smoke machines and a smoke wand.
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I find a length of heater hose held to the ear is pretty good. pass the other end round all the joints in the vac pipes and you'll soon hear even the smallest leak.
Worth getting a Lo-Gauge, though, just as a quick way to see if you have a problem in the first place, as said. :y
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This is what I found....
http://www.amazon.co.uk/Gunson-G4103-Gauge-Vacuum-Tester/dp/B0012MCW10
Where and how do you hook this up?
Cheers.
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I looked for vacuum leaks with carb cleaner and to be honest (due to space being tight in the engine bay) I'm not totally satisfied that I did it properly.
Plus there was the worry of it catching fire due to the carb cleaner being flammable.
So I searched a bit and found this....
http://www.youtube.com/watch?v=zMok2y05jNE
What do you think? Anyone tried this?
I'm going to give it a go this weekend.
:y
Ill have the cigar's when your finished with them :)
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This is what I found....
http://www.amazon.co.uk/Gunson-G4103-Gauge-Vacuum-Tester/dp/B0012MCW10
Where and how do you hook this up?
Cheers.
That's the chap. :y
If diagnosing the multirams I normally take off the vacuum feed to the solenoid on the front multiram and connect it there. You should see around 0.7 bar / 20In.Hg vacuum there at idle and it should remain static after stopping the engine if there are no leaks and the one-way valve in the vacuum tank is OK.
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This is what I found....
http://www.amazon.co.uk/Gunson-G4103-Gauge-Vacuum-Tester/dp/B0012MCW10
Where and how do you hook this up?
Cheers.
That's the chap. :y
If diagnosing the multirams I normally take off the vacuum feed to the solenoid on the front multiram and connect it there. You should see around 0.7 bar / 20In.Hg vacuum there at idle and it should remain static after stopping the engine if there are no leaks and the one-way valve in the vacuum tank is OK.
Thanks Kev.
Sorry for being stoopid :-[ but where are multirams? Will attaching the device there check for leaks throughout the whole inlet manifold? (plenum, hoses, trumpets etc )
:)
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I looked for vacuum leaks with carb cleaner and to be honest (due to space being tight in the engine bay) I'm not totally satisfied that I did it properly.
Plus there was the worry of it catching fire due to the carb cleaner being flammable.
So I searched a bit and found this....
http://www.youtube.com/watch?v=zMok2y05jNE (http://www.youtube.com/watch?v=zMok2y05jNE)
What do you think? Anyone tried this?
I'm going to give it a go this weekend.
:y
I found out that cigarette/cigar smoke tests to be successful when there is an air leak (unless fuel was spilled around ;D ) I dont use a hose .. just take some puffs and bring cigarette closer to possible areas and if it sucks the smoke , you find it..
ps: not in a windy day ;D
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Thats another way of doing it Cem.
I think when I do it (as an experiment) I'll open the throttle butterflies and launch it in the inlets from there. and then try the trumpets too
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Right, now I'm home and had a chance to investigate this vac gauge test....
i hook the gauge up anywhere on a vac line between the throttle body and engine, turn on engine and the needle should sit and not fluctuate. correct?
as for where to put said gauge, is this what kev was talking about....???
(http://i1226.photobucket.com/albums/ee402/webbybear1/vacgaugetest_zps7fa05b44.png)
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Yes, that would be a good place to connect it to check the vacuum supply to the multirams. :y
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Yes, that would be a good place to connect it to check the vacuum supply to the multirams. :y
Thank you mate. Much appreciated.
Will this also confirm vacuum leaks in the whole of the intake manifold or do I need to connect it somewhere else for that?
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Not really. A major leak will reduce the vacuum a little, but there can be other reasons for this (cam timing out being one example).
Leaks elsewhere are where you need the length of heater hose and a Mk.1 earhole. ;)
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Not really. A major leak will reduce the vacuum a little, but there can be other reasons for this (cam timing out being one example).
Leaks elsewhere are where you need the length of heater hose and a Mk.1 earhole. ;)
Fair enough mate. Sorry to be stupid here though but with this tool (vac gauge) is there nowhere i can hook it up to check for vacuum leaks in the intake manifold which would give the same (if not much more precise results) as the carb cleaner round hoses in the engine bay? if so i'm not going to spend the dosh and as you say, ill just revert to the heater hose. :y
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had another thought on this....
as i'm doing a compression test (ordering kit tomorrow) if the results of that are good i'm thinking healthy engine and no vac leaks? :-\
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Compression test will only tell you cylinder condition, nothing else.
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Not really. A major leak will reduce the vacuum a little, but there can be other reasons for this (cam timing out being one example).
Leaks elsewhere are where you need the length of heater hose and a Mk.1 earhole. ;)
Fair enough mate. Sorry to be stupid here though but with this tool (vac gauge) is there nowhere i can hook it up to check for vacuum leaks in the intake manifold which would give the same (if not much more precise results) as the carb cleaner round hoses in the engine bay? if so i'm not going to spend the dosh and as you say, ill just revert to the heater hose. :y
The only way you could test vacuum in the 'rest' of the intake is with the engine running - the vacuum measured being a result of the engine attempting to pump air into the cylinders past the restrictions of air filter, pipework, throttle butterflies etc (you'd find negligible vacuum before the throttle butterflies and much more after, for example, at all but full throttle).. what that means is you can hook up a vac gauge and see 'vacuum' but it's hard to say what it should read as every engine is different and 'right' will vary hugely depending on ambient conditions, engine condition, how the ECU is maintaining idle etc etc.
When you hook the vac gauge up where Kevin indicated you will, with the engine running, see the same thing - a varying vacuum. The important test, then, is after you stop the engine. As there's a one-way valve in the feed to the vacuum system and a vacuum reservoir you should find that when you switch the engine off, vacuum is maintained there - it shouldn't escape anywhere thanks to the valve and sealed nature of the system. If it does then you've found (somewhere) a vacuum leak in the pipework or vacuum reservoir that exist after the one-way valve. In this case it's not so much how much vacuum you see that is important but the fact that it doesn't (quickly) reduce to atmospheric pressure.
If you're looking for vacuum leaks in the rest of the intake system - e.g. inlet manifold to sandwich O-rings or IACV gasket on a non-DBW - then your options are (IMHO, others may disagree):
1) Mk.1 ear with a pipe and the engine running, as Kevin says - a vacuum leak will sound like a squeal through that, like a stuck pig.
2) Plug the air intake somewhere after any fresh air vent for the PCV system and fill it with smoke, look for the smoke escaping. Can be problematic on modern cars as there are so many vacuum and ventilation feeds and the PCV system is relatively complex that you can end up worrying about nothing as you fill the crank case with smoke.. ;D
3) Plug the air intake at the throttle bodies and pressurise the intake (slightly!) to, say, 4-5psi with a foot pump. Now use the Mk.1 ear again but this time you can do it with the engine off and listen for a hiss.
3) is more effective on a turbocharged car where the intake system is designed to see positive pressure as you can usually test from the turbo or even the MAF downstream, rather than just the throttle bodies.
Incidentally, I'd suggest thinking of the system as two separate parts when you're talking about looking for vacuum leaks..
There's the accessory vacuum system - this is the vacuum feed from the inlet manifold that goes to the brake master cylinder and services that along with all the other vacuum operated valves (multirams, heater bypass, heater control flaps, etc) - and there is the rest of the intake. On the Omega, the rest of the intake can be considered a vacuum system (as you are thinking of it), but on a turbocharged car that system will see positive pressure as well; it's not strictly a vacuum system.
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ok, this is what i'm going to do.
1. get a vac gauge. hook it up where i said in the picture i posted. run the car and switch it off and look for it to stay vacuumed.
2. go round the whole intake past the throttle body with my 10mm fuel line listening for squealing pigs.
3. i'm going to switch off and undo brake servo and pour some smoke in there just for the hell of it (got to find someone who smokes first lol) and see if that shows up anything.
i hope thats it cos its starting to get complicated for my little brain :( lol
cheers for all the input guys
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one final question...... if i blow smoke in to the plenum and i have the fron trumpets disconnected will smoke come out of the throttle butterflies or are they air tight? i'm presuming they're air tight so vacuum isbt lost at idle but just be interested to know :)
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one final question...... if i blow smoke in to the plenum and i have the fron trumpets disconnected will smoke come out of the throttle butterflies or are they air tight? i'm presuming they're air tight so vacuum isbt lost at idle but just be interested to know :)
throttle butterflies are air tight(ish) ;D
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one final question...... if i blow smoke in to the plenum and i have the fron trumpets disconnected will smoke come out of the throttle butterflies or are they air tight? i'm presuming they're air tight so vacuum isbt lost at idle but just be interested to know :)
throttle butterflies are air tight(ish) ;D
LOL!
I'll expect to see some smoke come out ::) ;D :y