Ditch
Member
Registered: 29th Nov 02
Location: St Albans Drives: JDM Celica GT4 WRC
User status: Offline
|
so if the secondary air pump pumps zaust gasses-(You say air?) through the CAT when its cold, what does the EGR do?!
|
Stu_22
Member
Registered: 25th Mar 02
Location: Luton
User status: Offline
|
Air pump pumps warm air to CAT so it warms up quicker as it works better when hot. No exhust gases
The EGR valve release some exhaust gas back into the air fuel mix into the inlet manifold.
CASE CLOSED
|
Ojc
Member
Registered: 14th Nov 00
Location: Reading: Drives : Clio 197
User status: Offline
|
No, right listen.
EGR is the hat thing on the front of the engine, you lot are getting confused.
Secondary air pump is also known as the EGR.
Darren, I don't know what this can of beans thing your talking about is.
Lee is gonna look at this thread now, I just rang him 
|
Stu_22
Member
Registered: 25th Mar 02
Location: Luton
User status: Offline
|
Put it in migweb they will sort it out
|
Ojc
Member
Registered: 14th Nov 00
Location: Reading: Drives : Clio 197
User status: Offline
|
I love you Stu.
|
3CorsaMeal
Member
Registered: 11th Apr 02
User status: Offline
|
just pull it off, and the little pipe
|
sassyminx
Member
Registered: 10th Jan 04
Location: Hartlepool Drives: Cossie
User status: Offline
|
i need mine blankin off just aint got a clue how to do it
|
3CorsaMeal
Member
Registered: 11th Apr 02
User status: Offline
|
ming rim it
|
sassyminx
Member
Registered: 10th Jan 04
Location: Hartlepool Drives: Cossie
User status: Offline
|
|
Joff
Member
Registered: 17th Oct 00
Location: Cambridgeshire
User status: Offline
|
Whats under the hat?
|
lee mitchell
Member
Registered: 26th Jan 01
Location: kent...drive's: eveyones conversion cars hard lol
User status: Offline
|
egr= exhaust gas recerculation. exhaust gases are recerculated. so obviously from the EXHAUST manifold
|
Colin
Member
Registered: 4th Apr 02
User status: Offline
|
quote:
Originally posted by sassyminx
i need mine blankin off just aint got a clue how to do it
Just use your finger....seemed to do the trick blanking off before
|
Marc
Member
Registered: 11th Aug 02
Location: York
User status: Offline
|
FPMSL
|
Stu_22
Member
Registered: 25th Mar 02
Location: Luton
User status: Offline
|
quote:
Originally posted by lee mitchell
egr= exhaust gas recerculation. exhaust gases are recerculated. so obviously from the EXHAUST manifold
Yes it come from the exhaust but not all of the exhaust goes back into a throught the engine so the EGR valve on the inlet manifold controls the flow, and at full throttle closes
|
Ojc
Member
Registered: 14th Nov 00
Location: Reading: Drives : Clio 197
User status: Offline
|
quote:
Originally posted by lee mitchell
egr= exhaust gas recerculation. exhaust gases are recerculated. so obviously from the EXHAUST manifold
Yes, look at that picture the exhaust gases go out of the hole and are pushed through that hat shaped thing through the rubber pipe on the right and into that horn shaped thing that runs parallel with the engine on the right hand side.
|
Stu_22
Member
Registered: 25th Mar 02
Location: Luton
User status: Offline
|
http://www.migweb.co.uk/forums/showthread.php?t=144509
|
Ojc
Member
Registered: 14th Nov 00
Location: Reading: Drives : Clio 197
User status: Offline
|
I think there getting confused I really do.
We will see tomorrow when I get the parts, but its funny how exhaust gases are escaping a hole in the manifold where the hat shaped thing goes and its not connected to the CAT in anyway shape or form.
|
jr
Member
Registered: 20th May 02
Location: Kent
User status: Offline
|
love you ollie, so technical
|
Stu_22
Member
Registered: 25th Mar 02
Location: Luton
User status: Offline
|
The manifold
[Edited on 16-08-2004 by Stu_22]
|
Ojc
Member
Registered: 14th Nov 00
Location: Reading: Drives : Clio 197
User status: Offline
|
So that thing attached to your manifold is what?
|
Marc
Member
Registered: 11th Aug 02
Location: York
User status: Offline
|
Is your car sprayed yet?
|
Rob H
Member
Registered: 28th Oct 00
Location: Staffordshire Drives: Astra SRi
User status: Offline
|
quote:
Originally posted by Ojc
Yes, look at that picture the exhaust gases go out of the hole and are pushed through that hat shaped thing through the rubber pipe on the right and into that horn shaped thing that runs parallel with the engine on the right hand side.
Oh come on, think about it rationally. Have you tried touching your exhaust manifold after youve just had the car running, even for about 20 seconds? It gets very hot, very quickly. Heat i think Rubber pipes wouldnt be able to withstand .
The EGR process is usually all carried out inside the head itself using special ports built into the design of it. Not 100% on it, but thats was my understanding.
Seriously though, you think they'd channel Exhaust gasses through rubber pipes and plastic components  .
[Edited on 16-08-2004 by Rob H]
|
jr
Member
Registered: 20th May 02
Location: Kent
User status: Offline
|
EGR Valves have been around for a long time. Way back in 1972 GM used them in an attempt to reduce emissions of oxides of nitrogen (NOx) which were a major cause of air pollution, mainly photochemical smog, that kind of smog which is formed when strong sunlight shines down on the exhaust gasses we puke out of our tailpipes by the billions of cubic feet a day.
A short chemistry lesson is in order here. It was discovered way back when, that high combustion chamber peak temperatures (the really short duration high temperatures near the end of the combustion process) caused oxygen and nitrogen to combine chemically and form these oxides of nitrogen mentioned above. Most of the anti-pollution devices of the day did a pretty good job of reducing the other bad by-products of combustion, namely excessive hydrocarbons and carbon monoxide, however they tended to induce the formation of oxides of nitrogen. Something had to be done else we would all die of smog diseases.
The automotive engineers figured that they needed to do something to lower the peak combustion temperatures which only occurred under certain high load driving conditions. They figured they could do so at the expense of power and fuel economy but what the heck, ya can't have everything! If they could only add something to the combustion chamber that would act like sort of a fire extinguisher to cool the combustion temperatures that would do it.
So they invented a way to allow some very inert gas to get back into the combustion chamber only when needed. They needed a source of this gas - it wasn't air, cuz that contains oxygen and nitrogen which caused the problem in the first place. So they chose carbon dioxide. Where to get a supply of carbon dioxide . . . ??? Hmmmm, how about the exhaust system? That is mainly carbon dioxide and water (plus a zillion other noxious chemicals) Suppose we allow some of the exhaust gas to get back into the intake manifold under strict control and only when we need it? That would cool the combustion chamber and prevent the formation of the NoX. Maybe we should call it recirculated exhaust gas (REG??). But a guy named Reginald voted no cuz he didn't want his name associated with a car part, so they called it exhaust gas recirculation (EGR) since there was nobody around with that name.
Now we understand why it is there. And we understand what it does. So what can go wrong with it and what are the symptoms??
It's really pretty simple - it can be open when it isn't supposed to be, or it can be closed when it is supposed to be open. Not rocket science, but it is science. If it is open when it is not supposed to be open, at idle for instance, It will act like one monster vacuum leak and the engine will not idle or will idle really roughly. If it doesn't open when it is supposed to open you will probably experience a symptom of "pinging" or "knocking" since the combustion chamber temperature will be higher than normal (one of the main causes of pinging in an engine).
There are a zillion different types of EGR valves some of which work strictly on vacuum, and some which work on a combination of vacuum and pressure. Some have electronic controls, some have mechanical controls. I won't go into detail here about all the different types but suffice it to say that most can be checked by looking inside to see if the plunger shaft is stuck open or doesn't move when the engine is revved up (after it is warmed up). Replacement is probably the easiest part since most are held in by two small bolts and have a vacuum line connected to it. The hard part is whipping out your Visa card to pay for it since most of them will drain your reserves in a hurry!!
|
jr
Member
Registered: 20th May 02
Location: Kent
User status: Offline
|
btw i dont know if the above is any use
|
Rob H
Member
Registered: 28th Oct 00
Location: Staffordshire Drives: Astra SRi
User status: Offline
|
quote:
Originally posted by jr
.... caused oxygen and nitrogen to combine chemically and form these oxides of nitrogen mentioned above.
So theoretically, your car's cooking on laughing gas, fo free .
|
