dweisel
Top Post Dawg
Must be ''PICK ON DWEISEL DAY'' Remind me next year and I'll stay away that day. lol.
dweisel
Hard Start / No Start - Is your intercooler frozen? Check Here!
- Thread starter GraniteRooster
- Start date
dweisel
dweisel
Top Post Dawg
Okay guys, its pay up time! Go remove your belly pan,disconnect the coldside intercooler hose at the mechanial fitting and place your hand over the end of the hose. IT SUCKS! In FACT it SUCKS so much it will colaspe the hose and stall the engine.
Please remit a $20 contribution through PayPal to the tdiclub in my name.
Thanks guys, its been fun.
dweisel
Please remit a $20 contribution through PayPal to the tdiclub in my name.
Thanks guys, its been fun.
dweisel
bhtooefr
TDIClub Enthusiast, ToofTek Inventor
Not so fast.
Put the hose back on, leave the mechanical fitting loose.
Idle the engine.
Is it sucking, blowing, or neither?
Put the hose back on, leave the mechanical fitting loose.
Idle the engine.
Is it sucking, blowing, or neither?
dweisel
Top Post Dawg
It SUCKS! At idle it SUCKS! At 2000 rpm it SUCKS! There is always suction. Maybe my turbo is install backwards? As I see it 4 out of 5 bets need to pay up. The other to be settled at a later date.
dweisel
dweisel
Top Post Dawg
It sucks!
Ski in NC
Top Post Dawg
That's not a valid test. You've disconnected the air inlet to the engine, of course it is going to suck!! The question is what is the pressure in the system when it is all connected.
This diversion is a waste of time. There is a real problem with icing/thawing/hydrolock. Whether there is a slight positive or neg pressure at idle has nothing to do with the problem nor the fix.
This diversion is a waste of time. There is a real problem with icing/thawing/hydrolock. Whether there is a slight positive or neg pressure at idle has nothing to do with the problem nor the fix.
MayorDJQ
Top Post Dawg
Slow down, Hot Rod:
You disconnected the hose on the passenger side, right?
That's the hose going to the intake manifold, so you just turned a turbo-charged engine into a naturally-aspirated engine. Of course it's going to suck when disconnected and the engine is running. The engine will draw in air to keep running.
Your experiment is invalid. Reinstall the hose so that the charge-air system is intact and operating normally. Then tap a vacuum gauge into it.
You disconnected the hose on the passenger side, right?
That's the hose going to the intake manifold, so you just turned a turbo-charged engine into a naturally-aspirated engine. Of course it's going to suck when disconnected and the engine is running. The engine will draw in air to keep running.
Your experiment is invalid. Reinstall the hose so that the charge-air system is intact and operating normally. Then tap a vacuum gauge into it.
GraniteRooster
Veteran Member
Dwiesel you've got this all tangled up making a mess of things. OF COURSE IT SUCKS - your engine is a positive displacement pump. Blocking it with your hand artificially blocks the intake - which does not happen in normal operation. You need to be measuring pressure with the turbo hooked up anyway!!
You intake is a free flow intake with negligible intake pressure drop - and the turbo is feeding the engine with pressurized air, as evidenced by MayorDJQ's logs. The turbo feeds the engine more air than it can swallow, thus if you have the pipes properly connected, you will find gauge pressures to match Mayor DJQ's plots.
This is not hard to understand - there is no magical mystery vacuum here.
You intake is a free flow intake with negligible intake pressure drop - and the turbo is feeding the engine with pressurized air, as evidenced by MayorDJQ's logs. The turbo feeds the engine more air than it can swallow, thus if you have the pipes properly connected, you will find gauge pressures to match Mayor DJQ's plots.
This is not hard to understand - there is no magical mystery vacuum here.
GraniteRooster
Veteran Member
Well said, enough of this
dweisel
Top Post Dawg
dweisel
Top Post Dawg
Ski in NC
Top Post Dawg
Don't give up. Just take a little time to understand the flowpaths in these things. Lots of hoses running around, but once sorted, it all makes sense.
tcp_ip_dude
Veteran Member
bhtooefr
TDIClub Enthusiast, ToofTek Inventor
Put the hose back on, with the fittings loose.
Of course that hose will suck when it's completely disconnected. (It also has abso****inglutely nothing to do with the problem.) Let me draw a diagram in MS Paint to show you why...
Of course that hose will suck when it's completely disconnected. (It also has abso****inglutely nothing to do with the problem.) Let me draw a diagram in MS Paint to show you why...
MayorDJQ
Top Post Dawg
Atmostphere--->Air Filter--->Turbo Charger Compressor--->Intercooler--->Intake Manifold--->Combustion Chamber--->Exhaust Manifold--->Turbo Charger Impeller--->OxCat/DPF--->Various Cats--->Muffler--->Tailpipe--->Atmosphere
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bhtooefr
TDIClub Enthusiast, ToofTek Inventor
I've left off the valve at the intercooler, the valve at the HPEGR, and the valve at the LPEGR.
Air comes in the airbox. Follow the path. Realize which hose you disconnected, and what happens to the air that's coming in there. When you realize what happens to that air, you'll see why that's not the cause of the intercooler icing.
GraniteRooster
Veteran Member
Yes, I had another episode today as well. Not amusing.
bsalbrig
Veteran Member
You have demonstrated nothing here. The reason a diesel doesn't create vacuum in its intake is there is no cut-off point as a gas engine has (throttle butterfly valve). Some diesel engines do have butterfly valves in the intake so they could create vacuum in the intake. Most diesel engines (these included) have open intakes as they are fuel regulated. There is no reason for them to have a restriction except for the anti-shudder valve and the swirl ports probably create some vacuum in their runners when they are blocked off.
To break it down for you what I am saying any engine will create a vacuum if the airflow is blocked off but diesels typically don't have a restriction because it is not needed.
Our cars have turbos...they force feed air to our engines. The pipe that you have disconnected will be discharging more air than your engine is consuming.
You are wrong....time to pay up.
To break it down for you what I am saying any engine will create a vacuum if the airflow is blocked off but diesels typically don't have a restriction because it is not needed.
Our cars have turbos...they force feed air to our engines. The pipe that you have disconnected will be discharging more air than your engine is consuming.
You are wrong....time to pay up.
GraniteRooster
Veteran Member
Nice Diagram
I've left off the valve at the intercooler, the valve at the HPEGR, and the valve at the LPEGR.
Air comes in the airbox. Follow the path. Realize which hose you disconnected, and what happens to the air that's coming in there. When you realize what happens to that air, you'll see why that's not the cause of the intercooler icing.
bhtooefr
TDIClub Enthusiast, ToofTek Inventor
I got the manifolds on the wrong sides of the engine, which complicated things, but hey.
What valve would there be at the IC?
MayorDJQ
Top Post Dawg
bsalbrig
Veteran Member
That isn't really a throttle valve is it? The only valves I know of in there is the anti-shudder valve and the intake runner valve.[/IMG]
nicklockard
Torque Dorque
That thing is a control system nightmare. It needs a differential equation computer to manage its NOx budget.
No wonder it has thermodynamic problems with condensate.
No wonder it has thermodynamic problems with condensate.
MayorDJQ
Top Post Dawg
There's no ASV on the CR engine. The "throttle" is a throttle, but not like on a gas engine. It's not there to affect the air/fuel ratio or create vacuum. It's used to control airflow and in conjunction with the EGRs to regulate EGTs.
There's a set of flaps on 4 of the 8 intake runners to create swirl in the air entering the combustion chamber.
Jack Frost
Veteran Member
My interpretation is much like yours in that the throttle is not there to create a vacume or affect air/fuel ratio. I think it might just be there to help the motor shut down quickly.
40X40
Experienced
jku72
Active member
Actually, it will suck. The engine, with the turbo disconnected from the circuit, becomes naturally aspirated. 4 stroke engines are something of a positive displacement air pump, so air flow is necessary all the time.
If the turbo is turning slow enough so as not to overcome the suction from the intake stroke of the piston, there may be a slight vacuum as well.
However, during most operation of the engine, the turbo is pumping air faster than the engine, so a positive pressure is formed, which overcomes the pumping losses of the engine, or, in other words, creates boost. On a long decelleration, such as coasting down a hill, it is likely that there is vacuum, at least a slight amount. This could account for some of the problems with icing.
Hope you understand what I am saying here.
If the turbo is turning slow enough so as not to overcome the suction from the intake stroke of the piston, there may be a slight vacuum as well.
However, during most operation of the engine, the turbo is pumping air faster than the engine, so a positive pressure is formed, which overcomes the pumping losses of the engine, or, in other words, creates boost. On a long decelleration, such as coasting down a hill, it is likely that there is vacuum, at least a slight amount. This could account for some of the problems with icing.
Hope you understand what I am saying here.
danham
Veteran Member
We have gone way off track here. Nobody to my knowledge is arguing that the engine is incapable of sucking water into the cylinders from the intercooler. We have reports of rough running, perhaps even hydrolock, and proof of presence of water in the plumbing.
So the question should be how to prevent excessive amounts of water from condensing in the intercooler in the first place. The ice issue is only relevant to the extent that temperature fluctuations are a contributing factor to condensation.
I'd propose "debate" about more relevant questions, such as, what happens when the temperature never drops below freezing? Does water still condense in the IC? If so, how is it dealt with without being sucked into the engine? In other words, our effort should be to find out more about how the system normally deals with moisture as a byproduct of combustion and then hopefully that will lead to why it fails to do so under certain fairly narrow conditions.
My gut feeling remains that short trips are a factor because the system does not reach operating temperature and stay there. VW tried to design for this with all the flaps and sensors and EGR loops and post-injection gimmicks to keep the system operating within a temp range that allows adequate performance and emission control. But that may not prevent excessive condensation as an unintended consequence.
-dan
So the question should be how to prevent excessive amounts of water from condensing in the intercooler in the first place. The ice issue is only relevant to the extent that temperature fluctuations are a contributing factor to condensation.
I'd propose "debate" about more relevant questions, such as, what happens when the temperature never drops below freezing? Does water still condense in the IC? If so, how is it dealt with without being sucked into the engine? In other words, our effort should be to find out more about how the system normally deals with moisture as a byproduct of combustion and then hopefully that will lead to why it fails to do so under certain fairly narrow conditions.
My gut feeling remains that short trips are a factor because the system does not reach operating temperature and stay there. VW tried to design for this with all the flaps and sensors and EGR loops and post-injection gimmicks to keep the system operating within a temp range that allows adequate performance and emission control. But that may not prevent excessive condensation as an unintended consequence.
-dan
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