Technical bad flutter on light throttle

[Argonought]

possibly? any ideas on why the noise goes when egr not connected and comes back when is connected?

I don't know for sure but remember the EGR valve is switched ON/OFF very quickly by the ECU. If you consider it under pressure from the exhaust (not certain if it would be :chin then with a leak around the tubing to the manifold (like I mentioned before) then you've just designed yourself a musical instrument

On the other hand, this leak would still be there when the EGR is shut (i.e. not being musical ) and you'd expect a side affect as the inlet manifold is unsealed.

If it's a leak it should be detectable. You could try the bubbly soap solution trick but take care you don't suck a lot of water into the manifold

 

[stilosporting]

I don't know for sure but remember the EGR valve is switched ON/OFF very quickly by the ECU. If you consider it under pressure from the exhaust (not certain if it would be :chin then with a leak around the tubing to the manifold (like I mentioned before) then you've just designed yourself a musical instrument

On the other hand, this leak would still be there when the EGR is shut (i.e. not being musical ) and you'd expect a side affect as the inlet manifold is unsealed.

If it's a leak it should be detectable. You could try the bubbly soap solution trick but take care you don't suck a lot of water into the manifold

when the egr is working would you expect it to be audible?

when i have just connected the egr back up and drove it sounds like it is spitting air at a specific rate. like you are hearing the egr working.

it could be that the pipe was leaking for a while before with the egr stuck shut and i have just got used to the sound of it. and now the egr is working again its making the leak more noticeable? i think i will price up two new egr pipes and if there not too expensive get them put on.

unless anyone could shed more light on it and diagnose a different cause?

 

[NumanR]

There seems to be alot of these light throttle flutter problems recently, I have one which I suspect could be due to the turbo actuator, but why so many problems all at once? Could there be a fuel issue?

 

[stilosporting]

mine has been doing it for probably a year now lol. just nowhere near as bad. until after the egr was replaced.

although for the record i mainly use shell filling stations.

 

[StiloSport]

I'm not sure if Fiat's operate the same way as VAG diesels do but on my Leon TDI, the EGR only works on part throttle and shuts completely on WOT. Also with VAGs, there is a small performance gain to be had by blocking the EGR valve but we're only talking 1bhp if that. It's mainly blocked or bypassed to reduce smoke after a remap. Not that this helps at all!:shrug:

 

[stilosporting]

i do think the jtd works in the same way. cheers for the input. how would it reduce smoke though if blocked? i thought the egr was to reduce smoke?

 

[Argonought]

As far as I know the EGR valve only produces smoke when jammed open or when the ECU is fooled into opening it (like when getting wrong MAF, MAP or boost info) at the wrong time.

I don't think you'd get much smoke when it's shut even if you are putting more unburnt fuel out the exhaust :chin:

 

[stilosporting]

ok ive been out in it today to try and diagnose it.

when the egr is connected i slowly accelerate. when i get around 2-2.5k rpm the noise/leak appears (i believe this is when the egr is opened under light acceleration).

when the egr is disconnected i slowly accelerate. i can go all the way to 4.5k rpm and the noise/leak does not apear at all.

what does this mean?

to see if it is a leak im going to put exhautst paste arount the pipe connections. im hoping then that either the noise will go as any leaks will be sealed up or the paste will be blown off and show where the leak is?

 

[StiloSport]

i do think the jtd works in the same way. cheers for the input. how would it reduce smoke though if blocked? i thought the egr was to reduce smoke?

The EGR valve (Exhaust Gas Recirculation) uses some of the exhaust fumes and feeds them back in to the engine and (supposedly) reduces emissions. This means that (on part throttle at least on VAGs) it never uses 100% "fresh" air. Bypassingblocking this valve means that no exhaust gasses can re-enter the engine resulting in a slightly cleaner burn. It's not the EGR valve's job to reduce smoke but emissions.

 

[stilosporting]

The EGR valve (Exhaust Gas Recirculation) uses some of the exhaust fumes and feeds them back in to the engine and (supposedly) reduces emissions. This means that (on part throttle at least on VAGs) it never uses 100% "fresh" air. Bypassingblocking this valve means that no exhaust gasses can re-enter the engine resulting in a slightly cleaner burn. It's not the EGR valve's job to reduce smoke but emissions.

that makes very good sense of it mate. cheers. well i might just blank it off if the problem continues and i cant resolve it. as one of the pipes i think is at fault is over £100. and when i just disconnect it i get an error message when the ecu tries to initiate it.

i noticed the plate that the bolts go through that connects to the bottom of the egr is warped ( bent outwards in the middle) so could be leaking from there??? should it be slightly curved?

 

[stilosporting]

As far as I know the EGR valve only produces smoke when jammed open or when the ECU is fooled into opening it (like when getting wrong MAF, MAP or boost info) at the wrong time.

I don't think you'd get much smoke when it's shut even if you are putting more unburnt fuel out the exhaust :chin:

so the egr doesnt open only as a result of rich exhaust gasses?

 

[StiloSport]

that makes very good sense of it mate. cheers. well i might just blank it off if the problem continues and i cant resolve it. as one of the pipes i think is at fault is over £100. and when i just disconnect it i get an error message when the ecu tries to initiate it.

i noticed the plate that the bolts go through that connects to the bottom of the egr is warped ( bent outwards in the middle) so could be leaking from there??? should it be slightly curved?

Yeah, you probably do get an ECU warning light, I do on my Leon too but I've got a program called VAG-COM that allows me to read and clear ecu faults, log performance of most engine components and alter body computer settings. Shame there isn't such a thing for FIATs.

Without seeing what your EGR valve looks like, I can't comment on what it should look like. Let me know next time there is a cruise and I'll pop down and bump in to you again and have a look!

 

[stilosporting]

Yeah, you probably do get an ECU warning light, I do on my Leon too but I've got a program called VAG-COM that allows me to read and clear ecu faults, log performance of most engine components and alter body computer settings. Shame there isn't such a thing for FIATs.

Without seeing what your EGR valve looks like, I can't comment on what it should look like. Let me know next time there is a cruise and I'll pop down and bump in to you again and have a look!

yeah sounds good.

there is equipment to read the ecu on fiats but they dont like jtds for some reason. ???

 

[StiloSport]

I don't know the answer to that fella, sometimes I think Fiat makes things deliberately difficult for their owners!

 

[Argonought]

so the egr doesnt open only as a result of rich exhaust gasses?

I don't think it has any means of knowing what the exhaust gases contain.

The ECU can measure how much air is going into the engine so it knows how much fuel the engine needs (it also know plenty of other stuff like the position of the throttle and existing engine load etc). If the ECU is happy the engine is only lightly loaded then it will open the EGR valve to let in unburnt exhaust gases (which have been cooled down) into the inlet manifold. Since this means less air is drawn through the MAF sensor then it follows the engine should need less fuel.

This is why the EGR system is considered good for economy (and reduced emissions).

The ECU will never open the EGR valve if you request Max Power :devil: so the affect on performance should be close to zero.

Have you noticed the weakness in the system? The whole thing goes haywire if the MAF is faulty :bang:

I can't believe you're thinking of disabling your brand new EGR valve

 

[NumanR]

Had a very interesting experience this morning, I drove 2 miles from cold and took the dog for a walk, after 30 minutes I restarted the engine and the engine stalled as I pulled away, after restarting the engine would not rev hardly at all and there was white smoke from the exhaust. (Remember this was a cold morning so this may have been due to water vapour) This continued for approx 2 minutes until I switched off and restarted a few times and then everything returned to normal. There are no fault codes (I am a Fiat DET), so as I didnt have a lot of time, I decided to blank off the egr valve. This has cured the light throttle fluttering I was experiencing.

Now if the egr valve sticks intermittently causing the fluttering, I think the egr valve stuck this morning in the open position and the engine never picked up properly due to this. Now when ever we have had egr problems at work it has always been when the performance is so bad diagnosis is easy (even though it never puts an error code in the ecu). What I would like to know is have other members had similar light throttle problems when the egr has failed soon after?

 

[StiloSport]

I can't believe you're thinking of disabling your brand new EGR valve

Why's that? If anything it's beneficial to the intake manifold. Take apart any TDI intake manifold and look at all the soot left due to the EGR valve "re-using" exhaust gasses. On 99% of cars, bypassing/blocking the EGR valve causes no problems come MOT time. Hell, even my 2.0 16v Astra runs smoother, pulls harder and is more economical since I've blocked the EGR valve and absolutely no problems what so ever in the last 2 mots.

 

[StiloSport]

http://www.stealthtdi.com/TDI-Problems.html

Some pics if you haven't got time to read the above...

 

[stilosporting]

the above is why i am going to clean the intake manifold as soon as.

numanr, what did you blank the egr off with? and so you know my flutter got worse when i fitted a new egr. iff all was working well are you supposed to hear the egr working?

argo, im only looking to blank it off until i can find the exact problem and sort it

 

[StiloSport]

There are 2 ways of blanking the egr valve. One is to find out which vacuum pipe (if yours is controlled by a vacuum) operates the valve, disconnect it and block the pipe with something like a golf tee or a screw (needs to be air tight!!!) and also block the connection on the egr valve to prevent any dirt going in to it.

The other way is to take apart the valve. Usually they are in 2 halves with a metal gasket in between the 2. Remove the gasket and trace the shape on to something like a coke can (doesn't matter if it's diet coke, pepsi, 7up etc.). Cut out the shape and make the holes for the bolts that hold the 2 halves of the egr valve together but do not cut the holes that are in the middle of the gasket, you don't want to allow exhaust gasses to pass through anymore. Fit the "new" gasket in place of the old one and re-assemble the egr valve. Make sure you keep the gasket you took out somewhere safe should you want to put it back to how it was.